-A 
ISBN TTfl-TflB-EDflfl-ai-fl 
9"789832"088318 
R U B B E R 
P L A N T A T I O N & 
P r o c e s s i n g T e c h n o l o g i e s 
R u b b e r 
P l a n t a t i o n 
a n d 
P r o c e s s i n g 
T e c h n o l o g i e s 
i 
w w w . l g m . g o v . m y 
Publisher 
Malaysian Rubber Board (MRB) 
(A Statutory Agency under the Ministry of Plantation Industries and Commodities) 
Tingkat 17 & 18, 
Bangunan Getah Asli, 
148, Jalan Ampang, 
50450 Kuala Lumpur, Malaysia 
Tel: 603-9206 2000 Email: general@lgm.gov.my 
Copyright © Malaysia Rubber Board 
No part of this publication may be produced in any form or any means electronic or 
mechanical, by photocopying, recording or otherwise, without the written permission 
of the publisher. 
First Edition 2009 
Perpustakaan Negara Malaysia 
Cataloging-in-publication Data 
Rubber plantation & processing technologies 
Include index 
Bibliography: p395-401 
ISBN 978-983-2088-31-8 
1. Rubber—History 
2. Rubber plantation 
633.8952 
F O R E W O R D 
Malaysia's success in the natural rubber industry, among other things, has been 
mainly attributed to the strong support of R & D, good management, the availability 
of trained personnel and also the industrious workforce. In the early years, Malaysia 
was only known as the leading natural rubber producer, but now, Malaysia has also 
been acknowledged as a leader in the export of quality rubber products. Although the 
rapid industrialisation taking place in the country has somewhat obscured the role of 
the agriculture, rubber still holds a niche in the growing Malaysian economy. Whilst 
it is true that rubber areas are reducing, one will see that the number of factories 
for the manufacture of rubber goods is steadily increasing in tandem with industrial 
development; and becoming more and more important. 
The RUBBER PLANTATION AND PROCESSING TECHNOLOGIES has been 
written with the sole aim to provide information and to serve as a text book on rubber 
for purposes of reference and practical utility. It is hoped that this integrated and self-
contained book will meet a long felt need among students and exponents of the art and 
science of rubber production. Scientists and students interested in the natural rubber 
industry will also greatly benefit by becoming acquainted with the various activities and 
practices governing the production of rubber. This book has been based on currently 
available information and it has made extensive use of the immense experience of the 
scientists gained throughout the years while they were in service with the Malaysian 
Rubber Board (MRB). 
Undoubtedly, this book will be invaluable to all those who are directly or 
indirectly involved in the rubber plantation sector. It is well documented with easy-to-
read diagrams, charts and photographs, and is also useful as a reference to those who 
are in the extension service and personnel dealing with the production of rubber. 
Books on natural rubber, inspite of its colourful and long history, are still 
considered few, and I strongly believe that this publication is aptly an addition that will 
share its days of glory both in the past and in the present. Last but not least I would like 
to congratulate the excellent job and tireless efforts of the team headed by the Director 
of Extension & Development Division who were entrusted with the task of adapting two 
earlier books written in Bahasa Malaysia and thereafter compiling the book. 
Dato' Dr Kamarul Baharain bin Basir 
Director General 
Malaysian Rubber Board 
ii 
P R E F A C E 
Rubber planting in Malaysia has been and will continue to be an important agricultural 
undertaking. It is still needed to accommodate those who are already involved in this 
venture. Malaysia is not only a major producer, but also an important consumer of 
natural rubber. Moreover, during the last two decades Malaysia has been the centre 
for rubber technology generation. It is therefore justifiable as well as appropriate for 
Malaysia to continue planting and producing rubber. However, the planting industry 
must be further updated and modernised. Early crop maturity and maximising yield 
must be the main aim now. This means that the adoption of technologies particularly 
by the smallholders who form the backbone of the rubber production sector is 
continuously utilised and sustained. The natural rubber industry in Malaysia will 
continue to be one of the major contributors to the national economy and a source 
of pride for those directly involved in the industry, particularly, the smallholders and 
rubber planters. 
This book is a revised adaptation of the two books written in Bahasa Malaysia 
entiled "Teknologi Getah Asli" and " Teknologi Perladangan dan Pemprosesan Getah" 
published in 1985 and 1994, respectively. It contains applicable technologies on 
rubber currently recommended and practised. There are ten chapters in all, out of 
which nine are technical. The first chapter provides an overview of the world natural 
rubber industry and an introduction to the Malaysian rubber industry. There are three 
sections consisting of glossary of terminologies found in this book, measurements 
and symbols. 
In the presentation of this book, materials have been drawn from several other 
RRIM/MRB publications. To these writers we wish to offer our deepest gratitude. Most 
significantly the contributions from the scientists, specialists in their respective fields, 
are readily acknowledged and appreciated. In a work of this kind it is impossible to 
enumerate all those who provided advice or assistance. It will, however, be remiss 
not to acknowledge the admirable achievement of the team who were given the task of 
compiling this book and editorial advice given by Puan Rabeatun Awaliah Awalludin, 
Head of Publications and Library Unit. Thanks are also due to Dr. Mohd Akbar Md. 
Said, MRB Deputy Director General (Research & Innovation) for the time and 
trouble he has taken to read through the manuscript and for his invaluable suggestions 
and ideas in improving the compilation of this book. 
Our great appreciation to the following for their contributions in making this 
publication possible: Tn Haji Abu Bakar bin Haji Ahmad (Original idea and draft), 
iii 
Dr. Othman bin Hashim (Coordinator), Pn V. Vanaja (Coordinator), Pn Masitah binti 
Arsad (Editing and Publishing), En Abd Latif bin Dalib (Administration), En Shahrir bin 
Mohd Salleh (Administration), En Azmi bin Din (Photography), En Ahmad Fadzil bin 
Ahmad Faiz (Typesetting), En Norzaid bin Kamarudin (Design input), En Azril Azmil 
bin Kamaluddin (Cover Design), Pn Haslira binti Khalid (Text Input), Unit Heads, 
Senior Officers and Staff of MRB (Inputs and updates). 
Finally, our thanks to Dato' Dr. Kamarul Baharain Basir, Director General of 
the MRB, for his permission to publish and for writing its foreword. 
We dedicate this book to all those who are involved in developing and upholding 
the rubber industry until the present time. They may be planters, smallholders, 
extension agents, supervision personnel and others. We urge and hope all of you 
will carry on the good work that you have put up thus far. With your commitment and 
concerted efforts the Malaysian natural rubber industry will continue to survive and be 
viable as a major contributor to the national economy for many years to come. 
Tuan Mohamad Tuan Muda 
Director Extension & Development Division 
iv 
C O N T E N T S 
Foreword i 
Preface iii 
List of Tables v 
List of Figures ix 
Chapter 1 INTRODUCTION 1 
Brief History 1 
World Rubber Industry 2 
Malaysia NR Industry 3 
Industry Outlook 12 
Chapter 2 DEVELOPMENT OF RUBBER CLONES 21 
Propagation of Rubber 24 
Planting Recommendations 29 
Seedlings 43 
Clonal Seed 43 
Rubber Seed and Its Germination 48 
Nurseries and the Production of Planting Materials 51 
Root Induction 67 
Chapter 3 SOILS AND LAND PREPARATION 69 
Soil Conservation 82 
Terracing 87 
Ground Cover Crops 89 
Chapter 4 PLANTATION DEVELOPMENT 97 
Work Operation 97 
Rubber Planting Design 111 
Field Lining 115 
Planting Perimeter Fencing 120 
Planting Hole 121 
Chapter 5 RUBBER PLANTING AND MIXED CROPPING 123 
Planting 123 
Mulching 127 
Mixed cropping 129 
Point Plan 136 
Chapter 6 FERTILISER APPLICATION AND FIELD MAINTENANCE 139 
Fertiliser and Its Function 139 
Replacement and Thinning Out 158 
Prunning 159 
Branch Induction 165 
Repairs and General Maintenance 170 
Tree Gowth Census 171 
Chapter 7 WEEDS AND THEIR CONTROL 173 
Chapter 8 TREATMENT OF MALADIES AND INJURIES AND 
CONTROL OF PESTS 185 
Root Diseases 185 
Stem Diseases 192 
Leaf Diseases 204 
Physical Injuries 211 
Pests 220 
Chapter 9 LATEX HARVESTING 247 
Tapping 247 
Exploitation Symbols 265 
Latex Yield Stimulation 270 
Ethephon-based Stimulant, MORTEX 276 
REACTORRIM Stimulation Technique 278 
RRIMFLOW Stimulation Technique 284 
Controlled Upward Tapping 297 
Tasking and Retasking 301 
Tapping Systems 303 
Exploitation Schedules 305 
Tapping Management 312 
Chapter 10 NATURAL RUBBER PROCESSING 315 
Cleanliness in Processing 316 
Preservation of Latex 318 
Dry Rubber Content in Latex 322 
Microwave Rapid Method for Determining Dry Rubber Content 
of Cuplumps 327 
Production of USS 330 
Smokehouse and the Drying of USS 340 
Grading of RSS 346 
Production of Block Rubber 352 
Production of Latex Concentrates 355 
Glossary 363 
Symbols 385 
Measurements 389 
References 393 
Index 397 
L I S T O F T A B L E S 
Table Page 
1.1 WORLD RUBBER PRODUCTION AND CONSUMPTION ('000 TONNES) 2000-2007 3 
1.2 AREA UNDER RUBBER IN MALAYSIA, THAILAND, INDONESIA, INDIA AND 4 
VIETNAM ('000 HA) 
1.3 PLANTED HECTARAGE OF NATURAL RUBBER ON ESTATES AND 5 
SMALLHOLDINGS IN MALAYSIA ('000 HA) 
1.4 NR PRODUCTION OF MAJOR NR PRODUCING COUNTRIES ('000 TONNES) 6 
1.5 MALAYSIA'S NATURAL RUBBER PRODUCTION AND YIELD 6 
1.6 MALAYSIA'S RUBBER CONSUMPTION BY TYPE (TONNES) 8 
1.7 EXPORT VALUE CONTRIBUTION OF THE MALAYSIAN NR INDUSTRY 9 
1.8 EXPORT OF RUBBER PRODUCTS BY PRODUCT SECTOR 10 
(VALUE IN RM MILLION) 
1.9 IMPORTS OF RUBBER PRODUCT SECTOR (RM MILLION) 11 
1.10 EXPORT VALUE CONTRIBUTION OF THE RUBBERWOOD PRODUCT 16 
SUB-SECTOR 
1.11 MALAYSIAN RUBBER DEVELOPMENT AGENCIES 17 
2.1 MEAN YIELD (KG/HA/YEAR) OF GROUP 1 LATEX-TIMBER CLONES 31 
2.2 SOME IMPORTANT CHARACTERISTICS OF GROUP 1 LATEX-TIMBER CLONES 31 
2.3 DISEASE SEVERITY OF GROUP 1 LATEX-TIMBER CLONES 32 
2.4 ESTIMATED WOOD VOLUME OF GROUP 1 LATEX-TIMBER CLONES 32 
2.5 MEAN YIELD (KG/HA/YEAR) OF GROUP 1 LATEX CLONES 33 
2.6 SOME IMPORTANT CHARACTERISTICS OF GROUP 1 LATEX CLONES 33 
2.7 DISEASE SEVERITY OF GROUP 1 LATEX CLONES 34 
2.8 MEAN YIELD (KG/HA/YEAR) OF GROUP 2A LATEX-TIMBER CLONES IN THE 35 
LARGE SCALE CLONE TRIALS 
2.9 MEAN GIRTH (CM) OF GROUP 2A LATEX -TIMBER CLONES IN THE LARGE 36 
SCALE CLONE TRIALS 
2.10 SOME IMPORTANT CHARACTERISTICS OF GROUP 2A RRIM 2000 SERIES 36 
LATEX -TIMBER CLONES 
2.11 DISEASE SEVERITY OF GROUP 2A RRIM 2000 SERIES LATEX -TIMBER 36 
CLONES IN MONITORED DEVELOPMENT PROJECTS 
2.12 ESTIMATED WOOD VOLUME FOR GROUP 2A LATEX-TIMBER CLONES 37 
2.13 MEAN YIELD (KG/HA/YEAR) OF GROUP 2A LATEX CLONES IN THE LARGE 37 
SCALE CLONES TRIALS 
2.14 MEAN GIRTH (CM) OF GROUP 2A LATEX CLONES IN THE LARGE SCALE 38 
CLONE TRIALS 
2.15 SOME IMPORTANT CHARACTERISTICS OF GROUP 2A LATEX CLONES OF 38 
RRIM 2000 SERIES 
2.16 DISEASE SEVERITY OF GROUP 2A LATEX CLONES OF RRIM 2000 SERIES IN 38 
SMALL SCALE CLONE TRIALS 
2.17 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES 39 
LATEX -TIMBER CLONES IN THE LARGE SCALE CLONE TRIALS 
2.18 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX-TIMBER 39 
CLONES IN THE SMALL SCALE CLONE TRIALS 
v 
2.19 SOME IMPORTANT CHARACTERISTICS OF GROUP 2B RRIM 2000 SERIES 40 
LATEX -TIMBER CLONES 
2.20 DISEASE SEVERITY OF GROUP 2B RRIM 2000 SERIES LATEX -TIMBER 40 
CLONES IN MONITORED DEVELOPMENT PROJECTS 
2.21 ESTIMATED WOOD VOLUME FOR GROUP 2B LATEX-TIMBER CLONES 41 
2.22 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX CLONES 42 
IN THE SMALL SCALE CLONE TRIALS 
2.23 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX CLONES 42 
IN THE LARGE SCALE CLONE TRIALS 
2.24 SOME IMPORTANT CHARACTERISTICS OF RECOMMENDED GROUP 2B RRIM 42 
2000 SERIES LATEX CLONES 
2.25 DISEASE SEVERITY OF GROUP 2B RRIM 2000 SERIES LATEX CLONES IN 43 
SMALL SCALE CLONE TRIALS 
2.26 COMMERCIAL YIELD IN KG/HA/YEAR OF RECOMMENDED SEEDLINGS 43 
2.27 PERCENTAGE GERMINATION OF RUBBER SEEDS EXPOSED TO SUNLIGHT 49 
2.28 EFFECT OF SIX ROOTSTOCKS ON GROWTH OF SCION 49 
2.29 TEN YEARS SCION YIELD 50 
2.30 SUGGESTED PLANTING DISTANCES IN RUBBER NURSERIES 54 
2.31 MANURING SCHEDULE FOR BUDSTICK MULTIPLICATION NURSERY 57 
2.32 MANURING SCHEDULE FOR BUDDED STUMP NURSERY 59 
2.33 MANURING SCHEDULE FOR BUDDED STUMP IN POLYBAG NURSERY 59 
2.34 MANURING SCHEDULE FOR YOUNG BUDDING NURSERY 61 
2.35 MANURING SCHEDULE FOR CORE STUMP NURSERY 63 
2.36 EFFECT OF IBA 2000 ROOT INDUCTION OF BUDDED STUMPS OF DIFFERENT 66 
GIRTH SIZES 
3.1 SOIL FRACTIONS AND THEIR DIAMETER SIZE LIMITS 73 
3.2 SOME SOIL SERIES IN RUBBER-GROWING AREAS OF PENINSULAR 76-78 
MALAYSIA 
3.3 SOIL PRODUCTIVITY CLASSES 80 
3.4 EFFECT OF COVER CROPS ON REDUCTION OF SOIL EROSION 85 
3.5 PLANTING POINTS FOR 500 PLANTS PER HECTARE ON TERRACE 88 
3.6 SOME COMMON LEGUME COVER PLANT SPECIES 90 
3.7 EFFECT OF COVER CROPS ON SOIL EROSION 91 
3.8 EFFECT OF COVERS ON FEEDER ROOT DEVELOPMENT OF RUBBER 91 
3.9 NUTRIENTS RETURNED TO THE SOIL IN FIVE YEARS BY TWO TYPES OF 91 
COVERS (KG/HA) 
3.10 EFFECT OF COVERS ON GROWTH OF RUBBER FIVE YEARS AFTER 91 
PLANTING (CM) 
3.11 EFFECT OF COVERS ON THE IMMATURITY PERIOD OF RUBBER 92 
3.12 EFFECT OF COVERS ON THE ACCUMULATED YIELD OF RUBBER (KG/HA) 92 
3.13 LEGUME COVER CROP SEED MIXTURES (KG/HA) 93 
4.1 SAMPLE WORK SCHEDULE FOR 2,000 HECTARES NEW PLANTING 100 
4.2 SAMPLE WORK SCHEDULE FOR 50 HECTARES REPLANTING 100 
4.3 RUBBER NEW PLANTING COST (RM/HA) 101 
4.4 RUBBER REPLANTING COST (RM/HA) 102 
vi 
4.5 EFFECT OF DRAINAGE ON YIELD OF CLONE PB 86 ON SELANGOR SERIES 107 
SOIL 
4.6 PLANTATION DRAIN SPECIFICATIONS 108 
4.7 RUBBER PLANTING DESIGN 112-113 
5.1 EFFECT OF DEEP PLANTING ON GROWTH OF YOUNG BUDDINGS OF PB 255 (I) 126 
5.2 EFFECT OF DEEP PLANTING ON GROWTH OF YOUNG BUDDINGS OF PB 255 (II) 126 
5.3 EFFECT OF MULCHING ON FEEDER ROOT DEVELOPMENT AND GROWTH OF 127 
MAXI STUMP BUDDING CLONE RRIM 600 
5.4 EFFECT OF VARIOUS TYPES OF MULCH ON GROWTH OF RRIM 600 127 
5.5 SUGGESTED SIGNS FOR POINT PLAN RECORDINGS 137 
6.1 EFFECT OF FERTILISER ON GROWTH OF TWENTY SEVEN MONTHS OLD 139 
RUBBER 
6.2 EFFECT OF NITROGEN ON YOUNG RUBBER ON SELANGOR SERIES SOIL 139 
6.3 EFFECT OF PHOSPHORUS ON GROWTH OF RUBBER 140 
6.4 EFFECT OF UREA ON GIRTHING RATE OF RUBBER AT 160 CM HEIGHT 140 
6.5 EFFECT OF DIFFERENT SOURCES OF PHOSPHATE ON GIRTHING RATE OF 140 
RUBBER AT 160 CM HEIGHT 
6.6 EFFECT OF FERTILISER ON BARK RENEWAL 141 
6.7 PLANT NUTRIENTS 143 
6.8 EXAMPLE OF STRAIGHT FERTILISERS 147 
6.9 RRIM-FORMULATED MIXTURE FERTILISERS 148 
6.10 SOME SLOW RELEASE FERTILISERS 149 
6.11 MANURING SCHEDULE FOR IMMATURE RUBBER IN THE FIELD 153 
6.12 GENERAL MANURING SCHEDULE FOR YOUNG RUBBER INLAND SOILS 154 
6.13 INTERIM GENERAL MANURING SCHEDULE FOR YOUNG RUBBER ON INLAND 155 
SOILS 
6.14 MANURING SCHEDULE FOR YOUNG RUBBER ON COASTAL CLAY SOILS 155 
6.15 MANURING SCHEDULE FOR REPLANTED MATURE RUBBER (KG/HA/YEAR) 156 
6.16 MANURING SCHEDULE FOR MATURE REPLANTED RUBBER (KG/TREE/YEAR) 156 
6.17 EFFECT OF CONTROLLED PRUNING ON GROWTH AND TAPPABILITY OF 159 
RRIM 600 
6.18 EFFECT OF CONTROLLED PRUNING ON TAPPABILITY AND YIELD 160 
6.19 EFFECT OF BRANCH INDUCTION ON GROWTH OF FOURTEEN MONTHS OLD 166 
TREES 
6.20 EFFECT OF BRANCH INDUCTION ON TREE HEIGHT OF FOURTEEN MONTHS 166 
OLD TREES 
7.1 EFFECT OF WEED UNDERGROWTH ON GROWTH OF RUBBER 174 
7.2 EFFECT OF WEEDS ON GROWTH OF RUBBER FIVE YEARS AFTER PLANTING 174 
(GIRTH OF TREE IN CM) 
7.3 EFFECT OF WEEDS ON IMMATURITY PERIOD OF RUBBER 174 
7.4 WEED CONTROL ROUNDS BY HERBICIDE SPRAYING 176 
7.5 TYPE OF HERBICIDES FOR YOUNG RUBBER AREA 177 
7.6 TYPE OF HERBICIDES FOR MATURE RUBBER AREA 178 
9.1 QUANTITY OF LATEX FLOW BY TIME OF TAPPING 250 
9.2 RINGS OF LATEX VESSELS SEVERED BY DEPTH OF TAPPING 251 
9.3 YEARLY BARK CONSUMPTION GUIDE 252 
vii 
i 
9.4 ADDITIONAL TAPPING DAYS AND YIELDS OBTAINED WITH THE USE OF 255 
RRIMGUD 
9.5 EFFECT OF ETHEPHON STIMULATION ON YIELD 271 
9.6 THE PREPARATION OF LOW CONCENTRATION ETHEPHON 274 
9.7 GUIDELINE FOR ETHEPHON STIMULATION 275 
9.8 RECOMMENDATION OF MORTEXAPPLICATION 277 
9.9 CLONAL RESPONSE ON YIELD FROM CONTROLLED UPWARD TAPPING 300 
9.10 MAPA-NUPW TAPPING TASK SIZES 302 
9.11 EXPLOITATION SYSTEM FOR BUDDINGS (I) 306 
9.12 EXPLOITATION SYSTEM FOR BUDDINGS (II) 307 
9.13 EXPLOITATION SYSTEM FOR BUDDINGS (III) 308 
9.14 EXPLOITATION SYSTEM FOR BUDDINGS (IV) 309 
9.15 EXPLOITATION SYSTEM FOR BUDDINGS (V) 310 
9.16 EXPLOITATION SYSTEM FOR BUDDINGS (VI) 310 
9.17 EXPLOITATION SYSTEM FOR CLONAL SEEDLINGS 311 
10.1 HNS-AMMONIA PRESERVATIVE SYSTEM 319 
10.2 HNS-AMMONIA STOCK SOLUTION 320 
10.3 BORIC ACID-AMMONIA PRESERVATIVE SYSTEM 320 
10.4 BORIC ACID-AMMONIA STOCK SOLUTION 320 
10.5 TMTD-ZNO-AMMONIA PRESERVATIVE SYSTEM 321 
10.6 TMTD-ZNO-AMMONIA STOCK SOLUTION 321 
10.7 COMPOSITION OF LATEX 322 
10.8 EFFECT OF SOME ADULTERANTS AND EXTERNAL TREATMENTS OF FIELD 327 
LATEX ON METROLAC DRC 
10.9 DILUTION OF FORMIC ACID 336 
10.10 DCL-ALL-ALLUMINIUM LATEX COAGULATING TANKS 336 
10.11 PRICE OF RSS (SEN/KG) 348 
10.12 CHEMICALS USED IN BLOCK RUBBER (SMR) PRODUCTION (PERCENTAGE OF 352 
DRC WEIGHT OF LATEX) 
10.13 BLOCK SMR SPECIFICATIONS 356 
10.14 PRESERVATIVE SYSTEMS FOR LATEX CONCENTRATES 358 
10.15 BASIC TEST AND SPECIFICATION LIMITS OF CENTRIFUGED LATEX 359 
CONCENTRATE 
10.16 TEST ANALYSIS OF SKIM RUBBER 362 
viii 
L I S T O F F I G U R E S 
Figure Page 
2.1 Profile of a Perfect Tree 23 
2.2 Hand Pollination Process 24 
2.3 Green Budding Process 26 
2.4 Young Budding Process 27-28 
2.5 Flowchart Showing The Different Stages of Testing Different Type 29 
of Clones 
2.6 Schematic Shape of Seed Gardens-Square and Rectangular 44 
2.7 Arrangement of Clones in Seed Garden 45-47 
2.8 Various Sizes of Rubber Seeds from Different Clones 48 
2.9 Germinating Rubber Seeds 51 
2.10 Establishment of Polybag Nursery 53 
2.11 Ground Nursery 54 
2.12 Transplanting Budded Stumps Into Polybags 55 
2.13 Preparing Core Stump Nursery 56 
2.14 Producing Green Budsticks 58 
2.15 Production of Budded Stumps 60 
2.16 Polybags Budded Stump Nursery Where the Scion Shoots Have 61 
Emerged to Two Hardened Whorls of Leaves and Ready for 
Transplanting 
2.17 Manuring Young Budding Materials 62 
2.18 Production of High Budding Materials 64 
2.19 Production of Core Stumps 65 
2.20 Effect of IBA on Root Development of Budded Stumps 67 
3.1 A Typical Soil Profile 70 
3.2 Soil Textural Classes Guide 74 
3.3 Various Types of Soil Pebbler 75 
3.4 Various Types of Soil Erosion 84 
3.5 Contour Terracing and Bunding 85 
3.6 Cross-Section of Terrace 87 
3.7 Layout for Planting Point Adjustment Along Terrace 88 
3.8 Plan of Legume Cover Crop Drills For Flat Land and Hill Slope 93 
3.9 Planting Out Legume Cover Crop Seeds 94 
3.10 Manuring Legume Cover Crops 95 
4.1 Manually-Cleared Jungle Area for Rubber Cultivation 104 
4.2 Clearing Old Rubber Area for Replanting 105 
4.3 Zero Burning Replanting 106 
4.4 Plan of Plantation Drainage 108 
ix 
4.5 Cambered Road Surface 110 
4.6 Square Planting Design 116 
4.7 Triangular Planting Design 117 
4.8 Determining the Inter-Contour Distance on a Hill Slope 117 
4.9 Contour Lining A Hilly Area-A Plan of the Contoured Hill and Cross- 119 
Section of the Same Hill 
4.10 Contour Lining Equipment 120 
4.11 Preparing Planting Holes 122 
5.1 Planting Polybag Material 124-125 
5.2 Lalang (Brass (Imperata Cylindrica) Used as Mulching Materials 128 
5.3 Various Types of Mixed Cropping 129-130 
5.4 Various Mixed Crop Planting Designs 131-134 
5.5 Different Types of Hedge Planting 135 
5.6 A Sample Point Plan of a Rubber Plot 137 
6.1 Major Nutrient Deficiency Symptoms in Rubber Leaves (First leaf 145-146 
from the left is not deficient) 
6.2 Fertiliser Application for Young Rubber Trees Less Than 15 Months 150 
(Circle Broadcasting) 
6.3 Diagram Showing Method of Fertiliser Application on Young 151 
Rubber 
6.4 Diagram Showing Placement of Fertiliser Application on Mature 151 
Rubber Trees 
6.5 Application of Fertiliser for Immature and Mature Trees 152 
6.6 Nutrient Cycle in the Rubber Plantations 157 
6.7 Example of Corrective Prunings 161 
6.8 Various Types of Controlled Pruning 162-164 
6.9 Pruning Technique 164 
6.10 Effect of Branching on the Rubber Tree 166 
6.11 Inducing Branches 167-169 
7.1 Several Noxious Weed Species 178-179 
7.2 Knapsack Sprayers of 18 Litres Capacity-Brass and PVC 180 
7.3 Various Types of Nozzle 181 
7.4 Herbicide Spraying Along Planting Strips 182 
7.5 Planting Strip After Spraying of Herbicide 182 
7.6 Use Suitable Protective Clothing When Spraying 183 
8.1 Major Root Diseases 186 
8.2 Applying Collar Protectant to Diseased Roots 188 
8.3 Treating White Root Diseased-Tree by Chemical Drenching 189 
8.4 Cross-Section of Isolation Trench 190 
8.5 Plan of Root Disease Patch Isolation 190 
8.6 Minor Root Disease 191-192 
8.7 Types of Stem Disease 193-202 
x 
8.8 Controlling Brown Bast or Tree Dryness 204 
8.9 Types of Leaf Disease 205-210 
8.10 Types of Physical Injury 211-216 
8.11 Types of Wind Damage and Their Treatments 217-219 
8.12 Major Insects 221-236 
8.13 Mollusc, Mammalian and Pest Damages 238-246 
9.1 Direction of Tapping Cut 247 
9.2 Slope of Tapping Cut 248 
9.3 Height of Tapping and Girth Size 249 
9.4 Three Dimensional Cross-Section of the Bark of the Rubber Tree 250 
9.5 Cross-Section of the Bark Showing Depth of Tapping 251 
9.6 Cross-Section of the Bark Showing Thickness of Tapping 252 
9.7 Monthly Bark Consumption Guide Marking 253 
9.8 Development of Tapping Knives In Malaysia 254 
9.9 Rainguard 255 
9.10 Girth Size Marking 256 
9.11 Girth Measurement 257 
9.12 Determining Slope of Tapping Cut 258 
9.13 Marking The Tapping Cut and Opening of Tapping Panel 259-260 
9.14 PVC Latex Cup Fitted With Lid and Funnel Known as RRIMCUP 261 
9.15 Position of Tapping Panels and Latex Cups for Leaning Trees 262 
9.16 Tapping of a Rubber Tree. A Pulling Cut is Made Right Down to 263 
the Bottom Corner of Panel 
9.17 Collection of Latex 264 
9.18 Concentration of Ethephon Available in the Market 272 
9.19 Ethephon Application Techniques 273 
9.20 Ethephon-Based Stimulant, MORTEX 276 
9.21 Applying MORTEX on the Groove 276 
9.22 REACTORRIM Stimulation Technique 279 
9.23 REACTORRIM Components 280 
9.24 Fixing Procedures of REACTORRIM 281-282 
9.25 Regassing of REACTORRIM Canister 283 
9.26 RRIMFLOW Stimulation Technique 284 
9.27 RRIMFLOW Components 285 
9.28 Fixing Procedures of RRIMFLOW 285-287 
9.29 RRIMFLOW Gassing Procedures in the Field 288 
9.30 G-FLEX and Its Placement 290 
9.31 Components of G-FLEX 290 
9.32 Additional Components (G-FLEX) 291 
9.33 Procedure of Fixing G-FLEX 292-293 
xi 
9.34 Procedure of Gassing in the Field 294 
9.35 Do-It-Yourself Techniques of G-FLEX 295 
9.36 The Controlled Upward Tapping (CUT) Knife 297 
9.37 CUT System for the Upper Panel 298 
9.38 Opening the Controlled Upward Tapping (CUT) Panel 299 
9.39 Succession of Tapping Panels for Buddings (I) 306 
9.40 Succession of Tapping Panels for Buddings (Ii) 307 
9.41 Succession of Tapping Panels for Buddings (Iii) 308 
9.42 Succession of Tapping Panels for Buddings (Iv) 309 
9.43 Succession of Tapping Panels for Buddings V and Vi 310 
9.44 Succession of Tapping Panels for Clonal Seedings 311 
10.1 Natural Rubber Prosessing 316 
10.2 Apparatus for the Determination of DRC of Latex by the Laboratory 324 
Method 
10.3 Apparatus for the Determination of DRC of Latex by the Dipper or 325 
"Chee" Method 
10.4 Apparatus for the Determination of DRC of Latex by the 325 
Hydrometer Metrolac Method 
10.5 Field Trial Using the Rapid Method at a Rubber Dealer Premise 328 
10.6 Cuplump with Minimal Contamination 329 
10.7 Cuplump Samples Before Drying 329 
10.8 Cuplump Samples After Drying with Appropriate Setting 329 
10.9 Uniformly Dried Cuplump Samples to Confirm Complete Drying 329 
10.10 Preparation of Creped Cuplumps for Microwave Rapid Method and 330 
Creped Cuplumps After Drying 
10.11(a) DRC Determination Through Visual Observation 331 
10.11(b) DRC Determination Through Price Cut Mechanisms 331 
10.12 Usage of Guideline in Rubber Plantation 332 
10.13 Sampling Areas For National Guideline on Determination of Dry 333 
Rubber Content of Cuplumps Throughout Peninsular Malaysia 
10.14 Examples of Good Quality Cuplumps 333 
10.15 Examples of Low Quality Cuplumps 334 
10.16 Bulk Processing of USS 337 
10.17 Processing of USS by Pan Coagulation Method 339-340 
10.18 Individual Processing of USS by Mini Coagulation Tank 341 
10.19 Various Designs of Smokehouse 344 
10.20 Smoking of USS 345 
10.21 Grades of RSS 349 
10.22 RSS Bales 351 
10.23 Processing of Block Rubber 353-354 
10.24 i4/fa Laval Latex Centrifuge Machine 358 
10.25 Flow Diagram of the Creaming Process 359 
xii 
CHAPTER 1 
INTRODUCTION 
Natural rubber (NR) is a major industrial raw material harvested from the rubber tree. 
Among the twenty odd plant species that are known to produce rubber, no less than 
twelve belong to the Hevea group. Out of these, only Hevea brasiliensis from the 
Euphorbiaceae family is economically exploited. The tree is a native of the Amazonian 
rain forest of South America. Hevea is a tropical crop that can survive within 1,000 km 
north and south of the equator, except for the arid regions. It requires 180-250 cm of 
rainfall per year and a temperature of 25-35 degrees Celcius. Rubber can be planted to 
a maximum elevation of 500 m above sea level. It requires a deep firm soil of the loamy 
texture with free drainage and tolerates a water table of 100 cm from the surface and 
below. The rubber tree is a perennial crop with an economic life-span of approximately 
thirty years. When fully matured, it can reach a height of 18-20 metres. Originally 
identified as a forest vegetation, Hevea wood is a valuable tropical timber which comes 
under the semi-hard category and most suitable for the furniture industry. Its latex, 
harvested from the tree, has been the major contributer to the NR industry towards the 
development of various rubber and rubber-based products. 
Brief History 
The existence of the rubber tree and its early crude product was internationally revealed 
as early as the Fifteenth Century, when Columbus discovered the Americas. Since 
then, raw rubber was taken to Europe from time to time. About 400 years later, several 
discoveries were made for its uses. Some of these earliest achievements were: 
• 1768 - Discovery of rubber boots 
• 1770 - The name "rubber" given by Priestley 
• 1823 - Waterproof fabric by Mcintosh 
• 1839 - Vulcanisation process by Goodyear 
• 1846 - Solid tyres by Hancock 
• 1888 - Pneumatic tyres by Dunlop 
The vulcanization process founded in 1839 was considered an important 
breakthrough in the development of the rubber industry, setting off its widespread planting. 
In 1876, some 70,000 seeds (later known as the Wickham's Collection) were taken from 
Brazil to the Royal Botanic Garden at Kew, England. In 1877, some of these seedlings were 
sent to Ceylon (now Sri Lanka), thirteen to the Singapore Botanic Garden and nine to Kuala 
1 
Kangsar. Perhaps this was how the rubber tree came to the East, and it is still believed that 
the rubber trees of today (in the East) originated from the Wickham's Collection. 
Early research and development (R&D) work on rubber was carried out from 
the small number of trees in the Singapore Botanic Garden. It was later intensified by 
H N Ridley when he became its Director in 1888. The most important development work 
pioneered by him was the excision tapping method of extracting latex from the tree. 
This is considered as another breakthrough that triggered the beginning of organised 
rubber planting in the East. This large-scale planting started when the first rubber estate 
was established in Melaka in 1903. In Peninsular Malaysia, early research in rubber 
was carried out by the Department of Agriculture, but as from 1925 onwards it became 
the entire responsibility of the Rubber Research Institute of Malaya (Malaysia) (RRIM). 
The RRIM became synonymous with advances in the NR industry which had been a 
resource centre of new technologies for the other NR producing countries as well. The 
R&D function is now amalgamated, together with the Tun Abdul Razak Research Centre 
(TARRC) in the United Kingdom, under the Malaysian Rubber Board (MRB) which was 
established in 1998 with the merger of the RRIM, the Malaysian Rubber Research and 
Development Board (MRRDB) and the Malaysian Rubber Exchange and Licensing 
Board (MRELB). MRB was given the task to advance and sustain the viability of rubber 
industry through its R&D, technical support and regulatory functions encompassing the 
upstream, processing and downstream sectors. 
World Rubber Industry 
World production and consumption of rubber, both natural and synthetic continued to 
increase in 2007. Total rubber consumption in 2007 increased to 22.90 million tonnes 
(Table 1.1). The growth rate in 2007 of 5.7% was the fastest pace in three years, i.e. 
the growth rates were 3.3% in 2006, 2 .1% in 2005 and 5.9% in 2004. NR comprised 
42.12% of total rubber production in 2007. Growth in 2007 was supported by the rapid 
increase in demand for rubber from countries within the Asia Pacific region and non-
EU Europe. World natural rubber (NR) consumption rose to 9.71 million tonnes (5.4%) 
as compared to synthetic rubber (SR) consumption at 13.19 million tonnes (a growth 
rate of 6.0%). Global SR share increased to 57.7% mainly as a result of the increase 
of consumption in the Asia Pacific. 
For NR, Asia has always been the main producer. In 2007, SR production 
increased to 13.32 million tonnes (4.4%). In contrast, due to weather problems, NR 
output was stagnant in 2007 at 9.7 million tonnes. Production in Thailand, Malaysia, 
India and Cambodia dropped in 2006 over 2007, but there were increases for Indonesia, 
Vietnam, China, Africa and Latin America. 
2 
TABLE 1.1 WORLD RUBBER PRODUCTION AND CONSUMPTION 
('000 TONNES) 2000-2007 
2000 2001 2002 ; 2003 2004 I 2005 
1 
2006 2007 
Natural Rubber (NR) 
Production 6,762 7,328 7,332 8,033 8,748 8,882 9,680 9,685 
Consumption 7,340 7,333 7,628 8,033 8,715 9,082 9,216 9,715 
Synthetic Rubber (SR) 
Production 10,870 10,483 10,882 11,390 12,019 12,155 12,762 13,310 
Consumption 10,830 10,253 10,692 11,371 11,839 11,895 12,446 13,188 
All Rubber (NR + SR) 
Production 17,632 17,811 18,214 19,423 20,767 21,037 22,442 22,995 
Consumption 18,170 17,586 18,320 19,404 20,554 20,977 21,662 22,903 
Source: International Rubber Study Group (IRSG) 
As for NR latex, there were declines in output in Thailand, Malaysia and India 
but increases were noted in China and Sri Lanka. But the net result indicated a shortage 
of supply against the increasing trend in demand. Hence, the sustained level of high 
prices of NR latex in 2007. 
Malaysian NR Industry 
The rubber industry has been a pillar of the Malaysian economy since 1950's and 
continues to be a major contributor until the present day. Though the planted area under 
rubber has been continuously declining since 1982, NR production remained at about 
1 million tonnes since 2004; indicative of increased land productivity. The importance 
of NR in terms of socio-economy cannot be denied as it sustains the livelihood of more 
than 200,000 smallholder families while the downstream manufacturing sector provides 
employment to over 64,000 workers. This sector made a significant contribution to the 
economy with total export earnings from three sub-sectors grew from RM5.3 billion in 
1990 to RM25.3 billion in 2007. Of this, export value share of rubber products stood 
at RM 10.09 billion followed by rubberwood products at RM7.96 billion and natural raw 
rubber RM 7.21 billion. Thanks to the Government's favourable industrial policies, the 
rubber industry has over the years diversified from planting (upstream) into downstream 
manufacturing. Today, Malaysia is world's No. 1 exporter of NR gloves, catheters and 
latex thread. 
3 
Planted Area 
NR planted area in 2007 was estimated at 1.25 million hectares, 183,000 hectares 
or 12.8% lower than the 2000's figure. During the period, both the smallholdings and 
estates sectors experienced decreases of 8.6% and 56.9% respectively (Table 1.3). 
The declines reflected the conversion of rubber area to the more profitable alternative 
investment opportunities both within and outside the sector. According to the Rubber 
Industry Smallholders Development Authority (RISDA), the rate of replanting of rubber 
to other crops in the smallholdings in 2000 was 38,026 hectares. Of this figure, 98% 
was converted to oil palm. The rate of decline in planted hectarage has however 
decreased with the return of high prices, sustained at encouraging levels over several 
years since 2003. The other major NR producers, however, expand their rubber areas 
from 2000-2007 (Table 1.2). This upward trend was led by Thailand with an increase of 
492,000 hectares, followed by Vietnam (138,000 hectares), India (72,000 hectares) and 
Indonesia (42,000 hectares). Currently the smallholder sector accounts for 95.7% of the 
Malaysia's planted area while the balance is under the estates (Table 1.3). 
TABLE 1.2 AREA UNDER RUBBER IN MALAYSIA, THAILAND, INDONESIA, 
INDIA DAN VIETNAM ('000 HA) 
Year Malaysia Thailand Indonesia India Vietnam 
2000 1,431 1,882 3,372 563 412 
2001 1,389 1,956 3,345 567 416 
2002 1,349 1,994 3,318 570 429 
2003 1,315 2,019 3,290 576 441 
2004 1,268 2,072 3,262 584 454 
2005 1,259 2,175 3,279 598 483 
2006 1,251 2,294 3,346 615 522 
2007 1,248 2,434 3,414 635 550 
Source: ANRPC; Monthly Bulletin 
Department of Statistics, Malaysia 
NR Production 
Malaysia is the third largest NR producer, producing 1.2 million tonnes in 2007 after 
Thailand (3.1 million tonnes) and Indonesia (2.8 million tonnes) (Table 1.4). Despite the 
shrinkage in planted area, production increased about 270,000 tonnes or 29.3% over 
2000. 
4 
TABLE 1.3 PLANTED HECTARAGE OF NATURAL RUBBER ON ESTATES AND SMALLHOLDINGS IN MALAYSIA ('000 HA) 
Year Peninsular Malaysia P.Malaysia Total. 
Sabah Sarawak Sabah & Sarawak 
Total 
Malaysia Total Grand 
Total Estate Smallholding Estate Smallholding Estate Smallholding Estate Smallholding 
1998 175.60 1,107.51 1,283.11 4.10 85.90 0.22 170.29 260.51 179.92 1,363.70 1,543.62 
1999 147.72 1,064.64 1,212.36 3.21 85.01 0.22 163.95 252.39 151.15 1,313.60 1,464.75 
2000 121.16 1,063.79 1,184.95 2.40 85.01 0.22 158.10 245.73 123.80 1,306.90 1,430.68 
2001 93.64 1,058.78 1,152.42 1.88 85.16 Nil 149.86 236.90 95.52 1,293.80 1,389.32 
2002 84.28 1,054.86 1,139.14 0.53 62.89 Nil 146.25 209.67 84.81 1,264.00 1,348.81 
2003 77.93 1,027.06 1,104.99 0.53 63.89 Nil 145.55 209.97 78.46 1,236.50 1,314.96 
2004 64.22 993.11 1,057.33 0.20 64.57 Nil 145.90 210.67 64.20 1,203.58 1,268.00 
2005 57.17 991.81 1,048.98 0.20 65.28 Nil 156.84 222.32 57.37 1,213.93 1,271.30 
2006 54.04 988.55 1,042.59 0.11 65.28 Nil 155.61 221.00 54.15 1,209.44 1,263.59 
2007 53.25 966.53 1,019.78 0.10 71.00 Nil 157.16 228.26 53.35 1,194.69 1,248.04 
Sources: Statistics for planted areas in Sabah - figures provided by Lembaga Industri Getah Sabah (LIGS) 
Statistics for planted areas in Sarawak - figures provided by Department of Agriculture Sarawak 
The data for total rubber planted area in Malaysia estimated by Malaysian Rubber Board 
TABLE 1.4 NR PRODUCTION OF MAJOR NR PRODUCING COUNTRIES ('000 TONNES) 
Year Thailand Indonesia Malaysia India Vietnam 
1998 2,076 1,714 886 591 218 
1999 2,155 1,599 769 620 262 
2000 2,346 1,501 928 629 291 
2001 2,320 1,607 882 632 313 
2002 2,615 1,630 890 641 331 
2003 2,876 1,792 986 707 364 
2004 2,984 2,066 1,169 743 419 
2005 2,937 2,271 1,126 772 482 
2006 3,137 2,637 1,284 853 555 
2007 3,056 2,755 1,200 807 602 
Source: International Rubber Study Group (IRSG) 
Department of Statistics Malaysia 
TABLE 1.5 MALAYSIA'S NATURAL RUBBER PRODUCTION AND YIELD 
Year 
Estate Smallholding 
Total 
Production 
('000 tonnes) 
Average 
Yield 
(kg/ha/yr) 
Production 
('000 
tonnes) 
Yield 
(kg/ha/yr) 
Production 
('000 tonnes) 
Yield 
(kg/ha/yr) 
1998 198.87 1,330 686.83 906 885.70 970 
1999 183.06 1,447 585.81 876 768.87 960 
2000 128.13 1,289 799.47 1,184 927.60 1,226 
2001 99.53 1,358 782.53 1,167 882.06 1,211 
2002 84.88 1,361 804.95 1,211 889.83 1,237 
2003 76.36 1,344 909.29 1,270 985.65 1,280 
2004 71.23 1,372 1,097.50 1,296 1,168.74 1,300 
2005 65.29 1,526 1,060.73 1,320 1,126.02 1,330 
2006 68.40 1,584 1,215.24 1,358 1,283.63 1,370 
2007 66.83 1,620 1,132.73 1,414 1,199.55 1,424 
Source: Department of Statistics Malaysia 
6 
Table 1.5 shows NR production from 1998-2007 in the estates and smallholdings 
sectors in Malaysia. Total production in 2007 was 1.20 million tonnes, 94% of which 
was contributed by the latter. Average land productivity of the estates sector was 1620 
kg/ha/yr while that of smallholdings was 1414 kg/ha/year. For the estates sector, output 
has persistently been on the declining trend despite the increase in yield; reflecting 
the considerable decrease in planted area. NR production in the smallholdings sector 
increased steadily after 2001 except for a marginal decline in 2007. 
Among the factors for Malaysia's decline in rubber production are as follows: 
Wet weather conditions throughout the year 
Decreasing area under rubber 
Slow adoption of modern technologies, especially among the smallholders 
Some areas having overaged trees and abandoned 
Some replanted areas with high yielding clones are not yet in production 
Domestic Consumption 
Total domestic consumption of rubber (NR and SR) in 2007 was 579,248 tonnes (Table 
1.6). This constitutes only about 2.5 % of the world total elastomer consumption. 
However, the above does not include the consumption of reclaimed and compounded 
rubber at 40,180 tonnes. Total NR:SR consumption ratio was 78:22. Trends indicated 
an annual increase in the consumption of SR since the 1990's. 
Malaysia is the largest consumer of natural rubber latex and the fifth-largest 
consumer of NR in the world. Importation of NR continued unabated to supplement 
seasonal shortfalls in local raw material to sustain the latex- and rubber-based 
manufacturing industries. Sources of import are mainly from South East Asian 
producers. However, with the declining production trend coupled with substantial 
increase in local usage and price advantages, the pressure was on for greater raw 
material importation, especially for latex concentrate. In 2007, a total of 605,120 tonnes 
rubber were imported. Of all the suppliers, Thailand became the most dominant source 
of imports, from only 13,990 tonnes in 1991 to 421,480 tonnes (69.7%) in 2007. 
Industry's Export Contribution 
The Malaysian rubber industry is a RM25 billion industry in 2007. Export value 
contribution of rubber products stood at RM 10.09 billion followed by raw rubber at 
RM7.21 billion. Rubber wood products contributed another RM7.96 billion mainly from 
the export of rubber wood-based industry (Table 1.7). Since 2001, rubber products and 
7 
TABLE 1.6 MALAYSIA'S RUBBER CONSUMPTION BY TYPE (TONNES) 
Year 
Natural Rubber Synthetic Rubber Total NR and SR 
Total 
rubber Tonnes %of World's Tonnes 
%of 
World's Tonnes 
NR.SR %of 
World's Ratio 
1990 172,997 3.33 14,595 0.15 187,592 92.2:7.8 1.3 187,592 
1995 307,750 5.13 44,145 0.48 351,895 87.5:12.5 2.3 351,895 
1996 360,784 5.90 46,668 0.49 407,452 88.6:11.4 2.6 407,452 
1997 360,188 5.57 48,857 0.49 409,045 88.1:11.9 2.5 409,045 
1998 333,310 5.07 43,309 0.44 376,619 88.5:11.5 2.3 376,619 
1999 344,447 5.18 57,587 0.56 402,034 85.7:14.3 2.4 402,034 
2000 363,715 4.99 55,608 0.51 419,323 86.7:13.3 2.3 419,323 
2001 400,888 5.46 57,699 0.56 458,587 87.5:12.5 2.6 458,587 
2002 407,884 5.35 63,150 0.59 471,034 86.6:13.4 2.6 471,034 
2003 421,781 5.47 66,452 0.58 488,233 86.4:13.6 2.5 488,233 
2004 402,769 4.88 84,236 0.73 487,005 82.7:17.3 2.5 498,321 
2005 386,472 4.42 96,417 0.81 482,889 80.0:20.0 2.4 494,582 
2006 383,324 4.32 112,385 0.91 495,709 77.1:22:9 2.3 518,834 
2007 450,246 4.62 129,002 0.98 579,248 77.7:22.3 2.5 619,428 
Source: Department of Statistics Malaysia 
International Rubber Study Group (IRSG). 
rubber wood sub-sectors indicated continued increase in export contribution. NR sub-
sector also registered an increase during the period except for a remarkable decrease 
in 2007 of RM1.0 billion or 12.5 % over 2006. 
Rubber Products Industry 
Only China, USA, Japan and India consume more rubber than Malaysia. The rubber 
products sub-sector contributes the highest in terms of export value. The composition of 
export contribution from this sub-sector is still skewed in favour of latex-based products at 
75% in 2007 (Table 1.8). Tyre and inner tubes contributed about 9% followed by general 
rubber goods (8%) and other products categories at about four percent. 
8 
TABLE 1.7 EXPORT VALUE CONTRIBUTION OF THE MALAYSIAN NR INDUSTRY 
Year 
Natural 
Rubber 
(RM billion) 
Rubber 
Products 
(RM billion) 
Heveawood 
Products 
(RM billion) 
Industry Total 
(RM billion) 
% Contribution to 
National Export 
2000 2.58 5.69 5.10 13.37 3.58 
2001 1.88 5.71 4.59 12.18 3.65 
2002 2.49 5.53 4.90 12.92 3.63 
2003 3.58 6.06 5.37 15.01 3.86 
2004 5.21 7.88 6.47 19.56 4.07 
2005 5.79 8.03 7.25 21.07 3.95 
2006 8.24 8.95 7.68 24.87 4.22 
2007 7.21 10.09 7.96 25.27 4.18 
Source: Department of Statistics Malaysia 
Malaysian Timber Industry Board (MTIB) 
Imports 
Malaysia imports of raw rubber in 2007 increased to over 600,000 tonnes as compared 
to 512,000 tonnes in 2006. Of the total, latex is about 57 percent. Thailand is Malaysia's 
major source of imported rubber followed by Indonesia, Vietnam and the Philippines. 
Since 2004, the industry imports approximately RM2 billion worth of rubber 
products mainly general rubber goods (GRGs) and tyres (Table 1.9). Other imports 
included industrial rubber goods (IRGs), latex goods, footwear and inner tubes. The 
general trend has been that of annual increase in the imports of rubber products. 
The large majority of companies involved in the production of industrial and 
general rubber goods are the small- and medium-scale enterprises (SMEs) comprising 
mainly of contract manufacturers to local and foreign companies. Strategic partnership 
and business alliances amongst some of the SMEs have led to improvements in 
production processes and technologies to enable them to move into the export market. 
In the highly labour intensive footwear industry, most locally-owned companies have 
relocated their operations in other countries particularly in the South East Asian region 
to capitalise on the relatively lower labour cost. 
g 
TABLE 1.8 EXPORT OF RUBBER PRODUCTS BY PRODUCT SECTOR 
(VALUE IN RM MILLION) 
Year Tyre Inner Tubes Footwear 
Latex 
Products 
Industrial 
Rubber 
Goods 
General 
Rubber 
Goods 
Industry Total 
Value 
%of 
National 
Exports 
1990 210.59 22.89 111.49 1,346.48 21.72 163.50 1,876.67 2.4 
1995 164.01 14.68 203.69 3,103.13 52.02 329.44 3,866.98 2.1 
1996 191.84 16.14 188.13 3,393.67 61.31 336.92 4,188.02 2.1 
1997 164.43 10.54 198.79 3,697.26 113.75 426.80 4,611.58 2.1 
1998 321.63 15.80 211.79 5.260.10 198.37 483.43 6,491.12 2.3 
1999 292.64 15.31 275.05 4,737.98 196.95 508.59 6,026.53 2.4 
2000 243.89 13.56 301.97 4,498.84 130.04 497.23 5,685.55 1.5 
2001 504.82 32.02 282.65 4,277.38 137.12 477.25 5,711.26 1.7 
2002 418.20 34.00 209.84 4,335.46 62.01 465.67 5,525.17 1.6 
2003 301.73 15.15 262.05 4,809.04 150.99 525.60 6,064.56 1.6 
2004 413.65 18.10 857.42 5,818.37 188.88 580.19 7,876.61 1.6 
2005 457.72 26.47 459.66 6,159.67 253.01 674.47 8,031.00 1.5 
2006 552.15 22.76 370.20 6,956.18 320.98 729.55 8,951.83 1.5 
2007 912.61 26.18 385.02 7,591.90 407.93 769.54 10,093.17 1.7 
Source: Department of Statistics Malaysia 
NR Prices 
One significant difference in the rubber industry scenario currently is the protracted 
high NR price level over the last four to five years. The encouraging price is expected 
to sustain and this single factor impacts significantly on the livelihood of thousands of 
smallholder families. Hevea as a timber species becomes relatively the more attractive 
species to be planted as a plantation crop for timber production. A slow down in the 
conversion of rubber land to oil palm is expected and a there may be a return to rubber 
plantation by the private sector in locations where conditions are favourable to rubber 
planting, especially to the demarcated rubber zones. 
10 
TABLE 1.9 IMPORTS OF RUBBER PRODUCTS BY PRODUCT SECTOR (RM MILLION) 
Year Tyres Inner Tubes Footwear 
Latex 
Products 
Industrial 
Rubber 
Goods 
General 
Rubber 
Goods 
Total 
%of 
National 
Imports 
1990 31.42 1.40 18.34 36.55 53.93 122.78 264.41 0.3 
1995 113.15 8.25 83.37 92.76 76.57 259.38 633.48 0.3 
1996 92.02 8.39 102.78 99.74 83.07 286.65 672.65 0.3 
1997 122.52 8.08 131.69 76.03 196.05 395.65 930.03 0.4 
1998 64.96 5.55 70.03 127.79 185.93 368.77 823.03 0.4 
1999 115.28 8.25 104.50 143.25 201.27 410.08 982.63 0.4 
2000 190.46 9.46 160.64 171.53 199.15 460.84 1,192.09 0.4 
2001 384.03 16.68 169.68 262.07 206.38 430.65 1,469.50 0.5 
2002 478.13 10.90 207.44 162.81 168.28 442.58 1,470.15 0.5 
2003 296.22 6.92 304.50 217.13 240.14 417.00 1,481.90 0.5 
2004 436.56 7.77 543.43 252.60 315.58 525.23 2,083.16 0.5 
2005 503.75 12.17 229.69 306.11 353.78 589.17 1,994.68 0.5 
2006 623.82 21.99 317.00 330.79 418.31 646.02 2,357.94 0.5 
2007 769.34 31.01 358.77 340.49 376.44 587.26 2,463.37 0.5 
. Source: Department of Statistics, Malaysia 
Since 2003, the scenario for the NR upstream plantation sector has been one of 
encouraging prices for growers. This is a departure from the traditionally depressed and 
protracted low prices of the 1980's and 1990's. Changes in world trade and economy, 
especially with the China factor and an unprecedented increase in oil prices, had 
impacted favourably on NR prices. The tripartite cooperation amongst the three leading 
world producers of rubber, Thailand, Indonesia and Malaysia, has also, to some extent, 
resulted in positive sentiments to sustain prices at reasonably high levels. Prices have 
increased steadily since the end of 2001 from a low SMR 20 fob price of 183.5 sen/kg 
in December 2001 to a record high of 894.5 sen/kg in month of July 2006. Since 2005, 
prices still fluctuated but hovered over a higher band of between 443 sen/kg to 894.5 
sen/kg and has breached the 1,000 sen/kg since June 2008. This higher band of prices 
has been sustained up to 2008 under present world economic scenario. 
11 
The latest development, in tandem with the rising price of crude oil, increasing 
production cost of SR and an increasing world demand for NR from the Asia Pacific 
regions has caused the price of rubber to surpass the RM 10.007kg mark for SMR 20 in 
June 2008. The rubber producers are hoping the world's prices for NR will be sustained 
over a long period to spur a renewed interest in the rubber industry. 
Industry Outlook 
Upstream Sector 
The rubber industry has gone through a significant structural change involving the 
smallholdings sector, which is less efficient in terms of rubber production compared 
to the estates sector. The former, which forms the backbone of the industry, is being 
given special attention. Smallholdings currently account for 95.7% of planted area 
and 94.4% of production. The average land productivity of the smallholdings sector 
in 2007 was 1,414 kg/ha/year compared to 1,620 kg/ha/year for the estates sector. 
The national yield average stood at 1,424 kg/ha/year in 2007. It is estimated that there 
will still be about 1.2 million hectare under rubber by the year 2010, of which 95% will 
remain as smallholdings. This area should be able to produce around 1.0 million tonnes 
annually provided that replanting programme is carried out at a targeted rate of 20,000 
ha annually. 
With reduced planted area and the need to maintain competitiveness, yield 
must increase via breeding, adoption of new latex harvesting technologies and sound 
agronomic practices. With better clones such as the Latex Timber Clones (LTCs), the 
national average yield should increase from 1,300 kg/ha a hectare to more than 1,700 
kg/hectare. LTCs are capable of high yields in latex and timber, which provide the raw 
materials needed for the rubber and rubber wood product industries. 
Clusters of smallholdings are encouraged to adopt new latex harvesting 
technologies under the low-intensity tapping system (LITS) concept while stimulation 
techniques to improve tree productivity, involving stimulation technologies such as 
MORTEX for young trees and gaseous stimulation for RRIMFLOW, REACTORRIM and 
G-FLEX, have to be introduced to offset the possible reduction in yield resulting from 
adopting LITS. The industry has been plagued by a shortage of labour, primarily skilled 
tappers causing severe reduction in national rubber production in early 2000 but the 
situation has been gradually recovered due to the present buoyant rubber price and the 
availability of foreign labour. 
12 
Midstream Sector 
For the midstream sector, the Government is focusing on increasing the efficiency 
in the processing of rubber, production of specialty rubbers for niche markets and 
competitive environment-friendly processing techniques locally and overseas. R&D is 
being conducted to add value to rubber-processing factories' effluents, which can be 
used for biochemical extractions. This includes the introduction of environment-friendly 
processing technology to minimise effluent and waste discharges, and applications of 
bioprocess technologies to produce value-added product such as quebrachitol, which 
is a chemical feedstock for the synthesis of bioactive material. 
Downstream Sector 
There are three major product sub-sectors with potential for greater development which 
include: latex products, industrial and general rubber products and tyres. The service 
sub-sectors comprise testing and certification of rubber products. Malaysia has an edge 
over other countries in terms of its R&D facilities, manufacturing technology, product 
design innovations and marketing capability. MRB shall capitalise on its strengths to 
maintain the lead. 
The rubber industry is expected to remain a strategic sector of the Malaysian 
economy even beyond 2020 if its diversification plans into higher value-added rubber 
products such as general (GRG) and industrial rubber goods (IRG) are any indication. 
The Government's support is the main driver of the industry's growth. The ongoing 
governmental efforts are aimed at strengthening the country's position as the leading 
manufacturer and exporter of latex products, expanding export markets for rubber 
products, building and retaining Malaysia's image as a supplier of quality rubber products 
and widening the present product range by developing the industrial and general rubber 
product sub-sectors. 
In particular, MRB is intensifying its efforts to promote the Standard Malaysian 
Glove (SMG) programme for the premium medical gloves. The programme aims at 
production of quality gloves which in turn will enable the industry players to fetch 
remunerative prices. According to MRB, consumers can be assured that SMG-certified 
gloves are high in barrier performance, the lowest in protein and powder contents, 
superior in tactile sensitivity, high in strength besides being environment-friendly. A total 
of 30 glove companies were certified as SMG manufacturers in 2007. 
13 
Research and Development Focus 
R&D is a crucial component that will provide an edge for Malaysian rubber products. 
MRB's R&D programmes have resulted in the development of high quality, technically-
specified rubbers suitable for the manufacture of specialised rubber products. Meanwhile, 
at its technology centres in Sungai Buloh and Brickendonbury, United Kingdom, MRB is 
engaged in R&D to improve efficiency and productivity in the manufacture of high value-
added products. Some potential R&D areas are in automotive rubber components, and 
development of NR for engineering, medical, military, sports and transportation. The 
private and public sectors should co-operate to develop rubber product manufacturing 
hubs and to spur growth as an approach to diversify the industry. 
The 'green' rubber Ekoprena is an environment-friendly processed rubber that 
can be used as a component for many rubber-based products. On the other hand, 
biotechnology can provide a new source of growth to develop genetically improved 
rubber trees and manufacture of value-added products in pharmaceutical and medical 
sectors. 
Latex Harvesting Technologies 
In late 1980's, the LITS concept was introduced and recommended for commercial 
adoption by the NR industry because of low rubber production. Due to enumerative 
factors, large productive rubber areas were left untapped. The income from rubber 
tapping became very unattractive compared with other economic activities. Most rubber 
holdings and estate owners resorted to employing foreigners for tapping rubber trees. 
Latex harvesting technologies under LITS concept were introduced and recommended 
to the NR industry for addresing issues of shortage of tappers. These technologies 
offer numerous advantages which have been proven in R&D activities carried out by 
the MRB. 
MRB has also introduced latex harvesting technologies for all ages of Hevea 
trees designed for increasing tree, tapper and land productivity and the income of tapper. 
Improvements have been made to the current conventional stimulation techniques based 
on feedback and continued R&D activities by MRB. The ethephon-based formulation 
(MORTEX) allowed more frequent applications which can be adopted from opening of 
tapping with more consistent high yield and minimal deleterious effect on the growth. 
The improved gaseous stimulation technique is characterised by more user-friendly 
gadgets and easier to operate and maintain devices. With relatively cheaper than other 
gaseous stimulation available in the market, this would encourage more smallholders to 
use this technique. 
14 
Rubber Forest Plantation for Timber Production 
In ensuring adequate supply of raw materials for downstream activities, rubber trees 
have been bred for dual purposes; namely, for the production of latex and timber. 
In contrast to the 30-year conventional replanting and wood harvesting, the rubber 
plantation for timber concept spanning a 15-year life cycle has been adopted with latex 
production scheduled between five to seven years before rubber trees are felled for 
timber. Hence, there is a need to develop exploitation systems which can produce higher 
land productivity from opening of tapping and sustained over the scheduled exploitation 
period starting from the ninth year after planting. Early results from the non-LTC clones 
showed that there are promising exploitation systems which can produce up to 2,000 
kg/ha/year. Irrespective of the purpose of rubber planting, appropriate and adequate 
agronomic inputs are required to ensure sustainable production. 
With good rubber prices and support from the government who is encouraging the 
establishment of rubber plantation for wood extraction through the provision of financial 
and fiscal incentives, the industry envisions the setting up of rubber plantation for timber 
on a large scale. As land is limited in Peninsular Malaysia, more rubber plantation would 
be established in Sabah and Sarawak. Strategies and action plans to meet anticipated 
surge in demand for planting materials are needed and must be periodically reviewed 
parallel with changes in the rate of establishment of rubber plantation for timber. At the 
same time, advisory and extension services must be extended to interested investors 
who are unfamiliar with the management of plantation crops such as rubber. 
Investments in rubber plantation for timber can be more attractive if the activity is 
fully integrated to take advantage of the attractive value-added revenue from downstream 
rubberwood processing and product manufacturing. Rubber plantation development is 
expected to be concentrated in Sabah and Sarawak in view of the huge concession areas 
that must be reforested with rubber as a timber species. Several saw-milling companies 
in East Malaysia have integrated upstream into the planting of Hevea in previously logged 
concession areas. The growth of rubberwood processing and rubberwood products 
manufacturing in Sabah and Sarawak could be a likely development strategy for the 
future. This reforestation programme will ensure adequate and uninterrupted wood supply 
while providing good margins from value-added processing. 
It is in the long-term interest of the rubberwood-based manufacturers to take 
steps to ensure that their enterprises are not jeopardised by any raw material shortages. 
Rubberwood products, especially furniture, have received very favourable responses 
from the world market and much of the potentials for both the product and its markets 
have yet to be fully tapped. In this light, private sector manufacturers should have the 
15 
foresight to invest in the future expansion of rubber plantation for timber. Malaysia still 
has the technical edge over other rubber producing countries as far as silviculture and 
agro-management of rubber trees are concerned. It has in stock some of the best bred 
species of rubber trees for plantation timber. Cognisance must be taken of these inherent 
advantages. The MRB as the custodian of the NR industry will continue to provide 
unrelenting support to all local parties involved in rubber forest planting activities. 
Rubberwood Products 
Growth of the rubberwood products manufacturing sub-sector continues to be 
encouraging amidst trends that indicate future shortage of rubber timber supply. Export 
revenue contribution from this sector overtook that of raw rubber since 1998 but fell 
behind in 2006 only on account of the unprecedented high raw rubber prices. Revenue 
from this sub-sector is expected to match that of rubber products in the near future. In 
2007, its export value contribution at RM 7.96 billion constituted about one-third of the 
total export value contribution of the rubber industry {Table 1.10). Rubberwood furniture 
exports account for 67% of the total export value contribution. The remarkable growth 
of the Malaysian furniture manufacturing sector is very much supported by rubberwood 
which accounts for some 80% of export revenue from all species of wooden furniture. 
TABLE 1.10 EXPORT VALUE CONTRIBUTION OF THE RUBBERWOOD 
PRODUCT SUB-SECTOR 
Products 
Export Value Contribution of Rubberwood Products 
2000 2001 2002 2003 2004 2005 2006 2007 
1 .Sawntimber 0 87 92 60 137 386 70 55 
2. Furniture 3,535 3,023 3,339 3,736 4,351 4,665 5,127 5,332 
3. Mouldings 313 224 229 208 647 698 796 915 
4. MDF 823 873 867 979 1021 1,107 1,145 1181 
5. Chipboard 160 134 1.16 102 196 267 267 365 
6. Builders' Carpentry & 
Joinery 269 243 261 281 110 116 103 102 
7. Wooden Frames - - - - 12 13 12 13 
Total 5,100 4,585 4,903 5,366 6,472 7,252 7,520 7,963 
Source: Malaysian Timber Industry Board (MTIB) 
Rubber Development Agencies 
In Malaysia there are several rubber development agencies, each one with specific 
functions, such as R&D, plantation development, financing, marketing, supervision and 
coordination. Table 1.11 lists out the various agencies involved and their functions. 
16 
TABLE 1.11 MALAYSIAN RUBBER DEVELOPMENT AGENCIES 
Names of Agency Functions 
Ministry of Plantation Industries and Commodities Coordination and supervision 
Ministry of Rural and Regional Development Coordination 
Ministry of Natural Resources and Environment Coordination and supervision 
Ministry of International Trade and Industry (MITI) Coordination and supervision 
Ministry of Higher Education Training development 
Ministry of Finance Supervision 
Ministry of Agriculture and Agro-Based Industry Training development 
Rubber Industry Smallholders Development Authority (RISDA) Planting development 
Federal Land Development Authority (FELDA) Planting development 
Federal Land Consolidation and Rehabilitation Authority (FELCRA) Planting development 
Kelantan Selatan Development Authority (KESEDAR) Plantation development 
Terengganu Tengah Development Authority (KETENGAH) Plantation development 
Johor Tenggara Development Authority (KEJORA) Plantation development 
Pahang Tenggara Development Authority (DARA) Plantation development 
Lembaga Kemajuan Perusahaan Pertanian Pahang (LKPPP) Plantation development 
Lembaga Urusan Tabung Haji Plantation development 
Farmers Organisation Authority Plantation development 
Sabah Rubber Industry Board (LIGS) Planting development 
Sabah Land Development Board Plantation development 
Sabah Forest Development Authority (SAFODA) Plantation development 
Sarawak Land Development Board 
Sarawak Land Consolidation and Rehabilitation Authority 
(SALCRA) 
Department of Agriculture Malaysia 
Plantation development 
Plantation development 
Training development 
Department of Agriculture Sabah Training development 
Department of Agriculture Sarawak (JPS) Training and planting development 
State Land Development Boards of Peninsular Malaysia Plantation development 
State Economic Development Corporations of Peninsular Malaysia Plantation development 
Department of Forestry of Peninsular Malaysia Plantation development 
Department of Forestry Sarawak Plantation development 
Department of Forestry Sabah Plantation development 
Malaysian Rubber Development Corporation (MARDEC Berhad) Processing and marketing development 
Malaysian Timber Industry Board (MTIB) Plantation development 
Kuala Lumpur Commodity Exchange Market development 
Malaysian Rubber Export Promotion Council (MREPC) Industrial promotion 
Malaysian Industrial Development Authority (MIDA) Industrial promotion 
With such numerous agencies dealing in rubber-related development, the continuance 
of this industry in Malaysia is something which is economically feasible. What is 
actually required is commitment from those involved. Some of the measures suggested 
towards achieving the vision, are: 
17 
• Replacement of rubber with other crops should be prohibited unless the soil is 
proven unsuitable 
• Replanting of smallholdings should, wherever possible, be carried out on group 
basis for more efficient management inputs 
• Where possible rubber should be planted with other perennial crops to avoid 
dependence on rubber alone 
• Provide some form of incentives, to attract the smallholders 
• Ensure a more active role of the extension services machinery of the development 
agencies so that modern technologies are adopted to the maximum by the rubber 
growers 
Sustaining the Malaysian Rubber Industry 
The world's demand for NR will be on an increasing trend especially with the emergence 
of rapid development among Asian countries such as China and India and the upsurge 
in crude oil price which may favour increased consumption of NR as compared to the 
the synthetic rubber. Malaysia needs to stay competitive in the global market and among 
the reasons why Malaysia must continue planting and producing rubber are: 
• Rubber is a strategic crop 
• Rubber planting is a source of income for the smallholders who are now the major 
players in terms of production and hectarage under rubber 
• It provides numerous job opportunities 
• Rubber production also contributes to national income 
• To supply the world's demand for natural rubber 
• To supply Malaysia's own need for the raw material, rubber-based products 
manufacturing and timber industries of Malaysia 
• To maintain Malaysia's position as one of the major NR producers 
• To contribute towards greening the world for a cleaner and healthier environment 
The prospect of NR industry is very promising in the near future due to its 
economic viability and sustainability which will continue to provide better socio-economic 
status to the smallholders. The good prices may encourage the younger generation 
smallholders to stay in rubber industry. Young graduates may involve themselves in the 
production process if it promises better income. This may be the beginning of a more 
educated and much younger smallholders wanting to move further into the production 
chain. 
Currently, the government places greater focus on agriculture as a major 
engine of growth. Rubber will assume greater importance as a sector for economic 
18 
expansion and income generation. As part of the national plans to make Malaysia a 
centre of excellence and a world leader in commodity-based industries, intensive efforts 
are on to improve the NR industry through education in plantation management, R&D 
and commercialisation of intellectual properties. It will be an integrated socio-economic 
entity that will ensure sufficient raw materials to sustain the requirements of the rubber 
processing, rubber products and rubber wood furniture sectors. The Malaysian rubber 
industry should grab this opportunity to produce more NR and gain maximum benefits 
from the current situation. 
19 
Henry Wickham (1876) 
The natural rubber industry owes a great debt to 
this specimen collector, explorer and trader 
H.N. Ridley (1888) 
He performed a one-man crusade persuading 
planters to attempt cultivation of rubber 
20 
CHAPTER 2 
DEVELOPMENT OF RUBBER CLONES 
The rubber tree is just like any other living plant of the same category. It consists of the 
crown at the top which contains the branches and the leaves, the stem or trunk in the 
middle and the root system below ground. 
The crown. The leaves grow on the leaf stalks, known as the petioles and 
connected by the petiolules. When the petiole falls off, a scar is left on the twig, branch 
or stem. The rubber tree defoliates its leaves annually, during the dry spell (January 
to March). This is known as wintering; the nature's way of preventing the water in the 
tree from being transpired through the leaves. The bud found between the petiole and 
the branch or stem is known as the axillary bud. The leaf scar left by the falling petiole 
also has a bud known as the scale bud. The bud that grows into a branch is known as 
latent, while the one that does not is called a dormant bud. At the very tip of the rubber 
plant there is also a bud known as the epical bud, which is ever-growing and forms the 
tree height. 
The rubber tree is a flower-bearing tree. The flowers are of the inflorescence 
type, where both the males and females can be found. They are attached to the axis, 
the central and the sides. The female flowers are found only at the tip of the axis 
(central and sides) and the male flowers in the inflorescence. The male flower contains 
the anther and the pollen grains, while the female contains the stigma and the ovary. 
When the pollen grains enter the female flower through the stigma, fertilisation takes 
place. This is known as the pollination process. In rubber, the main agent for pollination 
is insects. Pollination produces fruits consisting of two to five seeds in each pod. The 
time taken from pollination to seedfall is approximately five months. Pollination can 
also be done manually and this is known as hand pollination. Hand pollinated seeds 
are usually required for breeding purpose. The whole outer hard cover of the rubber 
seed and fruit is purely made up of the female tissue. Although the formation of the fruit 
cannot occur without fertilisation, no male tissue enters it. The embryo which is found in 
the centre of the seed is the result of the union between the male and the female cells 
and inherits the characteristics of both. The embryo germinates and eventually grows 
into a tree. Seeds of a single mother tree (clone) exhibit visual characteristics that can 
be accurately identified. 
The stem. The stem (also called as the trunk) consists of the central column 
known as the pith or medulla which is surrounded by the bark. The bark has three main 
21 
layers, the outermost of which is the soft bast where latex-bearing vessels are found. 
Between the bark and the wood is the cambium, a soft thin layer, which by mitosis 
keeps a supply of new conducting pipes for the upward and downward streams, by 
producing new wood cells inwardly and new bast outwardly as the tree grows in size. 
The medullary rays are horizontally situated in the bark. Their functions are to supply 
water to the bark in one direction and food to the wood in the other direction. Latex, 
which is the economic yield of the rubber tree, is found in the latex vessels. It is a 
whitish milky fluid containing rubber hydrocarbon in the form of small globules floating 
in an aqueous solution containing proteins, amino acids, carbohydrates and various 
electrolytes. Latex is still considered a byproduct of the rubber tree, but a highly useful 
raw material to mankind. 
The roots. The roots are part of the plant and are found in the soil. The rubber 
tree has three categories of roots. The tap root is the main central root that penetrates 
deep down the soil and keeps the rubber tree upright. The main and sub-laterals grow 
on it and provide anchorage to the tree. Feeder roots, which are numerous, grow on 
the laterals. Their functions are to absorb water by osmosis. At the tips of the feeder 
roots are the root hairs which absorb nutrient solution. The water absorbed by the 
feeder roots is forced into the central cylinder of the wood vessels and to the leaves. 
These remove the mineral food, retain water that is needed by the plant, and release 
the excess moisture through the stomata. The rubber tree takes in oxygen from the 
atmosphere through the stomata and lenticels, and gives out carbon dioxide as waste 
product of the respiratory process. 
Desired Characteristics of a Rubber Tree 
Rubber tree with desired characteristics will ensure its long term survival and at the 
same time will produce good yield throughout its economic life. It is important for the 
planters to have the knowledge on these desired characteristics as it will assist them 
when choosing good planting materials. The desired characteristics are: 
• The tree has good vigour to ensure early maturity and production. 
• Good girth increase when tapped, so that the stem is able to support the extended 
and heavy crown. 
• The size of the leaves must be broad with shiny dark green colour to ensure of good 
food supply for the tree through photosynthesis. 
• The main branches are well extended and growing upward to give balance to the 
crown. 
• The side branches should be small and balanced, growing laterally and orderly to 
maintain balance and give lighter crown. 
22 
• The tree must be shady and not easily shaken by wind. 
• The stem must be straight, smooth, well rounded and stood upright. 
• The virgin bark is thick and smooth for easy tapping. 
• The renewed bark is smooth, thick and quick to recover so that it can be re-tapped 
easily. 
• High yielding; and during wintering the yield will be maintained without much 
reduction. 
• Respond readily to yield stimulants. 
• Once tapped the tree immediately exudes latex with good flow. 
• When possible, the rate of tapping can be enhanced. 
• The latex is stable and has high dry rubber content. 
• The trees are not susceptible to diseases, wind damage and bark dryness. 
• The tree must be suitable to be planted in all kind of environments. 
It was found that all these desired characteristics are present in the existing 
rubber trees. However, not all of them were found in one tree. Further efforts are 
continued to produce a perfect rubber tree through breeding (Figure 2.1) 
CROWN - conical shape 
with broad base 
BRANCH - having a prominent 
leader and with side ones 
relatively small and horizontally 
positioned (wide angle 
attachment to the stem) 
LEAF - dark green, large 
and disease resistant 
STEM/TRUNK - Upright, 
straight, well-rounded 
and with good growth 
BARK - thick, smooth, 
giving high yield and with 
good renewals 
Figure 2.1 Profile of a perfect tree 
23 
PROPAGATION OF RUBBER 
Propagation can be defined as efforts to produce, increase or multiply quality planting 
materials, so that they are always available when required. Like any other living plant, 
the rubber tree terminates its life, by death or destruction due to diseases, pests or 
natural calamity. Therefore, to ensure its replacement, propagation of that particular 
tree must be carried out. The rubber tree can be propagated by sexual and vegetative 
means. 
Sexual Propagation 
Sexual propagation produces offsprings which have variations in their characteristics. 
This means that their performances and capabilities are not guaranteed, although the 
mother tree itself may be perfect. Propagation by this method is done through pollination 
which can occur naturally or manually. The process involves the removal of the anther 
containing pollen grains from the male flower and putting it in the stigma of the female 
flower. Fertilisation takes place. Fruit and seeds are formed, which mature in about five 
months (Figure 2.2). 
a) Pollinating rubber flower 
b) Rubber fruits 
Figure 2.2 Hand Pollination Process 
24 
Vegetative Propagation 
This method of propagation reproduces almost exactly the type of plant from where the 
propagated part is taken. In rubber, there are several propagation techniques, which 
can be broadly grouped into three, namely, cuttings, graftings and tissue culture. Among 
these, grafting is mostly preferred. Again, in grafting there are several options such as 
approach-grafting, cleft-grafting, root/seed-grafting and budgrafting. But budgrafting 
is the most popular as it is the simplest and guarantees higher grafting success. 
Budgrafting of rubber was first introduced in Sumatra in 1917 and is known as brown or 
conventional budding. From this, the green budding technique was developed in 1958. 
Further improvement on this led to the development of young budding in 1968. In this 
book, only the green and young budding techniques are described. 
Green budding 
One of the components for the green budding technique is the seedling stock of five to 
six months old, which can either be raised in polybags, ground nursery or open field. 
The stock should attain a stem size of 1.25 cm in diameter at the base. The other 
component is the bud which is taken from leafy green shoot of desired clones. To start 
budding operation, the base of the stock plant is wiped clean with a piece of cloth or 
rag. Two vertical cuts are made at the base of the stock stem, 7.5 cm high and 1 cm 
apart, and they are joined by a horizontal cut either at the upper or lower end. The bark 
is then stripped off either upward or downward depending on where the horizontal cut 
was made. The bark is cut away leaving 1 cm of tongue to hold the budslip in position 
later on. This operation creates an exposed budding panel of 6.5 cm x 1 cm. It is 
important that this exposed panel is not touched or allowed to be dirtied or left too long 
and became dry. A budslip of 10 cm in length is cut away from the budstick, including 
a thin slice of the wood. The bark is peeled off to remove the wood. It should be 
ensured that the inner side of the bark is not touched, dirtied, bent, bruised or exposed 
for too long. One end of the budpatch is then carefully slipped into the tongue of the 
budding panel, and the other extra end of the budpatch, which is already touched by the 
fingers, is trimmed off to fit into the budding panel, ensuring at the same time that the 
budpatch is not placed upside-down. The budslip is then firmly secured by tying a piece 
of transparent polythene tape of 16 mm x 0.05 mm. The budpatch should still be visible 
after this. Three weeks later, if the budpatch is still green (with callus formation around 
it), the budding operation is successful. The stock stem is cut-back at 10 cm above the 
bottom end of the budding panel and at the same time the polythene tape is removed. 
The scion shoot is expected to sprout in two to three weeks (Figure 2.3). 
25 
d) Inserting budpatch into e) Securing the budpatch using f) Completed budding process 
the "tongue" polythene tape 
Figure 2.3 Green budding process 
Young budding 
In the young budding technique, the seedling stocks are raised in polybags of 18 cm 
x 38 cm layflat dimensions. They should reach buddable size in about ten weeks with 
basal diameter of 6 millimetres. The buds used are also green but much younger in 
age and smaller in size than normally used in green budding. As usual, the base of 
the stock plant is cleaned. Two vertical cuts are made at the base of the stock plant 
6 cm high and 0.6 cm apart, and joined by a horizontal cut at either the bottom or 
upper end. The bark is stripped off upward or downward depending on where the 
horizontal cut was made, and the bark is cut away leaving 1 cm of tongue to hold the 
budslip later on. This would expose a budding panel of 5 cm x 0.6 cm. Again, please 
ensure that this panel in not contaminated or left to dry. A budslip of 8 cm long is 
cut away from the budstick, including a thin slice of the wood. The bark is carefully 
26 
a) Making vertical and 
horizontal cuts 
b) Opening the flap c) Slicing the budstick 
j) Scion shoot that k) Polybags kept in the nursery I) Ready for transplanting 
has emerged 
Figure 2.4 Young budding process 
peeled off to remove the wood. The same precaution must be taken with regards to the 
budpatch as described in the green budding operation. One end of the budpatch is then 
inserted into the tongue of the budding panel, while ensuring its position is not upside-
down. The extra end of the budpatch already touched by the fingers is trimmed to fit 
into the budding panel. The budding can now be secured firmly by winding it around a 
transparent polythene tape of 16 mm x 0.05 mm in size. The budpatch should also be 
visible. Four weeks later, the budding can be inspected. A successful budding should 
have a budpatch which is still green with callus formation around it. The stock can be 
cut-back higher above the budding panel leaving two-leaf petioles on it to continue 
manufacturing food for the plant. All buds found on the stock snag must be removed by 
nicking to prevent them from sprouting. The stock can also be cut-back lower, leaving a 
much shorter snag as in the case of green budding, but this operation should be slightly 
delayed to a week or two to allow for the grafting to be hardened. In both cases the 
polythene strip binding the grafts must be removed. The scion is expected to appear in 
two to three weeks (Figure 2.4). 
28 
PLANTING RECOMMENDATIONS 
The MRB Planting Recommendations is updated every three years to provide information 
on the availability, status and performance of planting materials for the rubber planters. 
The MRB Planting Recommendations 2006 also follows the established format whereby 
the clones are recommended in two groups namely Group 1 and Group 2. However, 
Group 2 is further sub-divided into Group 2A and Group 2B to enable early selection 
among the newly recommended clones. Group 2A comprises all the clones, which 
showed good early performance in large-scale trials in different environments. All the 
newly recommended clones from the small scale trials are categorized in Group 2B as 
well as those clones which did not show good early performance in the various large 
scale clone trials. Figure 2.5 shows the different stages of testing of the different group 
of clones. 
Selection of Parents for Crossing 
Hand Pollination Programme 
1 
Hand Pollinated Seedling Trials 
Small Scale Clone Trials 
Large Scale Clone Trials 
Monitored Development Project 
Group 2B 
Clones 
Group 2A 
Clones 
t 
Group 1 
Clones 
Figure 2.5 Flowchart showing the different stages testing different type of clones 
The clones are further subdivided into latex-timber clones and latex clones in relation to 
their rubber and wood production as follows: 
29 
(i) Latex-timber clones (LTCs) are clones with high latex yield and rubberwood 
production. They exhibit good growth form such as good growth vigour and possess 
long straight boles. These clones are suitable for the production of latex and rubberwood 
or production of rubberwood only. 
(ii) Latex clones are clones capable of producing high latex yield but relatively low 
rubberwood yield. These clones are suitable for latex production and not suitable for 
rubberwood production. 
Group 1 
Group 1 consists of clones with known track records based on at least five years of 
non-stimulated yield data on BO-I and two years in BO-II and also information on the 
secondary characteristics in large scale trials e.g. Large Scale Clone Trials (LSCT), 
Monitored Development Projects (MDP) or commercial planting. These clones are 
recommended for planting in estates and smallholdings without any restriction imposed 
on number of clones and size of planting. There are 14 clones of which ten are latex-
timber clones and the rest are latex clones. 
Latex-Timber Clones 
The clones are: RRIM 908, RRIM 911, RRIM 921, RRIM 928, RRIM 929, RRIM 936, 
PB 260, PB 350, PB 355 and PB 359. The yield data of the newly upgraded clones 
RRIM 928 and RRIM 929 and the PB clones viz. PB 350, PB 355, PB 359 and PB 366, 
are obtained from various LSCT up to the eighth year in different environments. The 
eight years mean yield of these clones ranged from 1200 kg/ha/year to 1690 kg/ha/year 
using V2S d/3 6d/7 tapping system (Table 2.1). The mean yields of the other clones over 
ten years tapping are 1300 kg/ha/year, 1630 kg/ha/year, 1490 kg/ha/year and 1630 kg/ 
ha/year for clones RRIM 908, RRIM 911, RRIM 921 and PB 260, respectively. Only 
clone RRIM 936 yields more than 2000 kg/ha/year, but it was tapped using 1/ 2S d/2 
6d/7 tapping system. The relatively lower yields recorded for these clones as compared 
to their genetic potential were due to the lower number of tapping days i.e. about 70 
tapping days per year. 
Some of the important secondary characteristics of Group 1 latex-timber clones 
are resistances to wind damage (varied from average to very good) and to major leaf 
and stem diseases (ranged from severe to no infection) (Tables 2.2 and 2.3). Most of 
these clones also showed below average to very good with respect to other secondary 
characteristics. The estimated wood production between 19-22 years after planting, 
ranged from 0.74 m 3/tree in RRIM 928 and RRIM 936 to 1.59 m3/tree in PB 355 (Table 
30 
TABLE 2.1 MEAN YIELD (KG/HA/YEAR) OF GROUP 1 LATEX-TIMBER CLONES 
Planting 
material 
Year of tapping 
Mean 
1 2 3 4 5 6 7 8 9 10 
RRIM 
908 929 1089 1491 1506 1561 1358 1395 1431 1193 1055 1301 
RRIM 
911 928 1464 1859 1799 1735 1668 1769 1841 1655 1599 1632 
RRIM 
921 960 1209 1518 1570 1709 1527 1565 1686 1684 1448 1488 
RRIM 
928 1249 1593 1644 1953 1336 1631 1641 1834 - - 1610 
RRIM 
929 1005 1225 1445 1585 1368 1503 1396 1796 - - 1415 
RRIM 
936* 1280 1800 2700 2670 2080 2690 2060 2220 2350 1610 2146 
PB 260 1349 1641 1496 1569 1339 1841 1996 1886 1701 1124 1594 
PB 350 1643 1552 1552 1898 1688 2191 2269 2102 - - 1862 
PB 355 723 1138 1146 1353 1241 1431 1403 1823 - - 1284 
PB 359 661 1083 1368 1507 1416 1499 1484 1538 - - 1320 
V4S d/3 6d/7 tapping system 
Data from Large Scale Clone Trials (LSCT) 
Trees per hectare: 327 + 34 
* y2 S d/2 6d/7 tapping system 
TABLE 2.2 SOME IMPORTANT CHARACTERISTICS OF GROUP 1 
LATEX-TIMBER CLONES 
Characteristic RRIM 908 
RRIM 
911 
RRIM 
921 
RRIM 
928 
RRIM 
929 
RRIM 
936 
PB 
260 
PB 
350 
PB 
355 
PB 
359 
Yield for first 
two years 4 4 4 4 3 5 4 5 2 2 
Yield third to 
tenth years 3 5 4 NA NA 5 5 NA NA NA 
Wintering 
depression 4 2 3 3 3 3 4 4 4 4 
Resistance to 
dryness 3 4 4 4 5 3 2 4 4 4 
Resistance to 
wind damage 3 3 5 5 5 4 3 4 4 4 
Vigour at 
opening 4 4 4 5 5 5 4 5 5 5 
Girth increment 
during tapping 3 4 3 3 2 3 3 4 4 4 
Virgin bark at 
opening 3 3 4 5 5 3 2 4 5 4 
Renewed bark 3 3 3 5 5 3 2 3 4 3 
5 = Very Good; 4 = Good; 3 = Average; 2 = Below Average; 1 = Poor, NA = Not available 
31 
2.4). The clear bole volume, measured from ground to the first persistent branch of the 
main trunk, ranged from 0.33 m3/tree in PB 350 to 0.63 m3/tree in RRIM 921. Generally, 
these clones have long, straight and smooth trunk characteristics. 
TABLE 2.3 DISEASE SEVERITY OF GROUP 1 LATEX-TIMBER CLONES* 
Characteristic RRIM 908 
RRIM 
911 
RRIM 
921 
RRIM 
928 
RRIM 
929 
RRIM 
936 
PB 
260 
PB 
350 
PB 
355 
PB 
359 
Pink disease 
(incidence) N N N N N N L N N N 
Oidium S S S L M M M M M M 
Colletotrichum M L L L L VL M VL N N 
Corynespora N L N N N VL N N N N 
N = Nil VL = Very light L = Light M = Moderate S = Severe 
* Data from disease surveys and clone trials 
TABLE 2.4 ESTIMATED WOOD VOLUME OF GROUP 1 LATEX-TIMBER CLONES 
Planting 
material 
Age 
(year) 
Clear bole volume 
(mVtree) 
Canopy wood volume 
(mVtree) 
Estimated total wood 
volume (m3/tree) 
RRIM 908 22 0.51 0.51 1.02 
RRIM 911 22 0.46 0.69 1.15 
RRIM 921 22 0.63 0.63 1.26 
RRIM 928 21 0.59 0.15 0.74 
RRIM 929 21 0.60 0.60 1.20 
RRIM 936 20 0.49 0.25 0.74 
PB 260 20 0.37 0.92 1.29 
PB 350* 19 0.33 0.83 1.16 
PB 355* 22 0.53 1.06 1.59 
PB 359* 20 0.42 1.05 1.47 
*Data from Golden Hope Plantations Bhd. Clonal Trials at Prang Besar 
32 
TABLE 2.5 MEAN YIELD (KG/HA/YEAR) OF GROUP 1 LATEX CLONES 
Planting 
material 
Year of tapping 
Mean 
1 2 3 4 5 6 7 8 9 10 
RRIM 938 1350 2220 3310 2310 1910 3460 1920 1930 2360 2150 2292 
PB 280 1090 1500 1890 2180 2240 2160 2310 2310 2290 2260 2023 
RRIM 901 1080 1710 2230 1980 2040 2990 2220 1720 1950 1790 1971 
PB 366" 1215 1376 1539 1677 1601 1789 1529 1541 - - 1533 
Tapping System: 1/2S d/2 6d/7 
No. of Tapping Days: 158 + 11 days 
Data from Large Scale Clone Trials (LSCT) 
Trees per Hectare: 327 + 34 
** Yield from LSCT using 1/2S d/3 6d/7 tapping system 
Some of the important secondary characteristics of Group 1 latex clones such as 
resistances to wind damage, varied from below average to very good, and to major 
leaf and stem diseases, ranged from severe to no infection (Tables 2.6 and 2.7). Most 
of these clones showed below average to very good with respect to other secondary 
characteristics. 
TABLE 2.6. SOME IMPORTANT CHARACTERISTICS OF GROUP 1 LATEX CLONES 
Characteristic RRIM 901 RRIM 938 PB 280 PB 366 
Yield for first two years 5 5 5 5 
Yield for third to tenth year 5 5 5 NA 
Wintering depression 1 3 4 4 
Resistance to dryness 2 2 4 4 
Resistance to wind damage 4 5 2 4 
Vigour at opening 4 5 3 5 
Girth increment during tapping 3 3 3 4 
Virgin bark at opening 4 4 5 4 
Renewed bark 3 4 5 3 
5 = Very Good; 4 = Good; 3 = Average; 2 = Below Average; 1 = Poor 
33 
TABLE 2.7. DISEASE SEVERITY OF GROUP 1 LATEX CLONES* 
Characteristic RRIM 901 RRIM 938 PB 280 PB 366 
Pink disease (incidence) S N N N 
Oidium M M M M 
Colletotrichum M VL L VL 
Corynespora L N N N 
N = Nil VL = Very light L = Light M = Moderate S = Severe 
* Data from disease surveys and clone trials 
Group 2 
Group 2 consists of 33 clones comprising 9 clones in Group 2A and 24 clones in 
Group 2B. Due to limited information on the performance of these clones in different 
environments, planting of clones from this group should comprise basket of clones and 
not more than 50% and 20% are from Group 2A and Group 2B, respectively. These 
respective clones should be planted in blocks in accordance to recommendation. 
Group 2A 
Group 2A consists of new clones, which showed good early performance of at least three 
years yield data in large-scale trials in different environments. This would allow rubber 
growers to choose new promising clones in Group 2 with low risk. Group 2A comprises 
seven latex-timber clones namely RRIM 2001, RRIM 2002, RRIM 2007 RRIM 2009, 
RRIM 2015 RRIM 2016 and RRIM 2019; and two latex clones namely RRIM 2004 and 
RRIM 2005. 
The five-year mean yields of the seven latex timber clones listed above, which 
were extrapolated from the Small Scale Clone Trials (SSCT) were 2850, 2350, 2710, 
2280,2760,2580 and 2410 kg/ha/year, respectively. Whereas, the five year mean yields 
of the latex clones in the SSCT were 2467 and 2432 kg/ha/year, respectively, thus, 
indicating that these are potentially high yielding clones in the initial stage of testing. 
These clones were further tested in the LSCT in different environmental conditions 
throughout the country. 
The three-year mean yields gram/tapping/tree (g/t/t) and kg/ha/yr of the seven 
latex timber clones from the LSCT are given in Table 2.8. Currently, only two trials 
had been tapped for three years. The other trials in different part of the country were 
established at a later date. Generally, the yield pattern increased from the first year to 
the third year tapping. 
34 
The mean yield in g/t/t ranged from 49 (RRIM 2002) to 74.20 (RRIM 2007) 
whereas, the mean yield in kg/ha/yr ranged from 1610 in RRIM 2016 to 28310 in RRIM 
2007. The differences in mean yield based on g/t/t and kg/ha/yr were due to the number 
of stand. Except for RRIM 2007, all the other clones had relatively lower mean yields 
as compared in the SSCT The yield of these clones is expected to increase further 
especially in the proceeding panels. 
TABLE 2.8. MEAN YIELD (KG/HA/YEAR) OF GROUP 2A LATEX-TIMBER CLONES IN THE 
LARGE SCALE CLONE TRIALS 
Planting 
material 
Year of tapping Mean 
1 2 3 
g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr 
RRIM 2001 56.91 1191 50.54 1739 55.74 2045 54.40 1658 
RRIM 2002 44.75 1102 51.94 1662 50.50 1732 49.06 1627 
RRIM 2007 63.45 2045 77.54 3088 81.59 3360 74.19 2831 
RRIM 2009 46.51 1342 49.01 1804 50.33 2005 48.62 1717 
RRIM 2015 34.27 1050 50.85 1952 53.51 2191 46.21 1731 
RRIM 2016 47.82 1152 57.20 1762 59.04 1921 54.69 1611 
RRIM 2019 40.30 1295 49.05 2081 65.79 2905 51.71 2093 
Tapping system: 1/2S d/3 6d/7 
Average of two trials 
The important secondary characteristics of these clones are summarised in 
Tables 2.9, 2.10 and 2.11. Most of the clones can be tapped at five years or earlier 
after planting. The clones showed high girth increment at immaturity, which ranged from 
9.1 cm/year to 10.0 cm/year for RRIM 2001 and RRIM 2009, respectively (Table 2.9). 
Generally, these clones showed good tolerance to wind damage and nil to moderate 
infection of various diseases in field trials and nursery screening (Tables 2.10 and 
2.11). 
35 
TABLE 2.9 MEAN GIRTH (CM) OF GROUP 2A LATEX-TIMBER CLONES 
IN THE LARGE SCALE CLONE TRIALS 
Planting material 
Year after planting Mean girth 
increment 
(cm) 2nd 3rd 4th 5th 
RRIM 2001 15.4 24.5 34.1 42.6 9.1 
RRIM 2002 17.1 27.2 37.0 45.4 9.4 
RRIM 2007 18.3 29.3 38.0 45.9 9.2 
RRIM 2009 15.9 29.7 37.0 46.0 10.0 
RRIM 2015 18.9 30.2 40.1 46.8 9.3 
RRIM 2016 17.7 28.9 38.7 47.4 9.9 
RRIM 2019 17.5 29.5 39.4 45.2 9.2 
Average of two trials 
TABLE 2.10 SOME IMPORTANT CHARACTERISTICS OF GROUP 2A RRIM 2000 SERIES 
LATEX-TIMBER CLONES 
Characteristic RRIM 2001 
RRIM 
2002 
RRIM 
2007 
RRIM 
2009 
RRIM 
2015 
RRIM 
2016 
RRIM 
2019 
Yield for first two years 5 5 5 5 5 5 4 
Resistance to wind 
damage 4 4 4 4 4 4 4 
Vigour at opening 5 4 5 4 4 4 4 
Virgin bark at opening 5 4 4 4 4 4 4 
5= very good; 4 = good; 3 = average; 2=below average; 1=poor 
TABLE 2.11 DISEASE SEVERITY OF GROUP 2A RRIM 2000 SERIES LATEX-TIMBER 
CLONES IN MONITORED DEVELOPMENT PROJECTS 
Characteristic RRIM 2001 
RRIM 
2002 
RRIM 
2007 
RRIM 
2009 
RRIM 
2015 
RRIM 
2016 
RRIM 
2019 
RRIM 
2020 
Pink disease (incidence) L N N N N L N L 
Oidium M M L M M M L M 
Colletotrichum M L M M L M M M 
Corynespora L N L L L L N L 
Phytopthora N N N N N M M S 
N = Nil VL = Very light L = Light M = Moderate S = Severe 
36 
The estimated wood volume of the Group 2A latex-timber clones at the age 
of 14-17 years after planting ranged from 0.60 to 1.28 m3/tree for RRIM 2007 to RRIM 
2015, respectively (Table 2.12). Most of these clones showed high wood production. 
The bole wood volume, which is the premier wood, was also high ranging from 0.20 to 
0.44 m 3/tree. 
TABLE 2.12 ESTIMATED WOOD VOLUME FOR GROUP 2A LATEX-TIMBER CLONES* 
Planting material Age (years) 
Clear bole volume 
(m3/tree) 
Canopy wood 
volume (m3/tree) 
Total wood volume 
(mVtree) 
RRIM 2001 17 0.41 0.82 1.23 
RRIM 2002 17 0.44 0.66 1.10 
RRIM 2007 14 0.20 0.40 0.60 
RRIM 2009 14 0.34 0.34 0.68 
RRIM 2015 14 0.43 0.87 1.30 
RRIM 2016 14 0.43 0.85 1.28 
* Estimated wood volume from Small Scale Clone Trials (SSCT) 
The two latex clones in Group 2A showed high mean yields after three years 
tapping with 2280 kg/ha/yr and 2030 kg/ha/yr for RRIM 2004 and RRIM 2005, respectively 
(Table 2.13). The important secondary characteristics of these clones are summarised 
in Tables 2.14, 2.15 and 2.16. These clones showed good girth increment at immaturity. 
Except for severe infection of Colletotrichum in RRIM 2005, these clones showed good 
tolerance to wind damage and nil to moderate infection of various diseases in field trials 
and nursery screening. 
TABLE 2.13 MEAN YIELD (KG/HA/YEAR) OF GROUP 2A LATEX CLONES 
IN THE LARGE SCALE CLONE TRIALS 
Planting 
material 
Year of tapping Mean 
1 2 3 
g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr 
RRIM 2004 49.57 1085 70.23 2343 89.35 3362 69.72 2263 
RRIM 2005 65.79 999 77.69 2049 104.32 3045 82.60 2031 
Tapping system: YiS d/3 6d/7 
Average of two trials 
37 
TABLE 2.14 MEAN GIRTH (CM) OF GROUP 2A LATEX CLONES 
IN THE LARGE SCALE CLONE TRIALS 
Planting material 
Year after planting Mean girth 
increment (cm) 2nd 3rd 4th 5th 
RRIM 2004 15.5 26.0 35.0 41.9 8.8 
RRIM 2005 16.4 25.9 35.0 41.9 8.5 
Average of two trials 
TABLE 2.15 SOME IMPORTANT CHARACTERISTICS OF GROUP 2A 
LATEX CLONES OF RRIM 2000 SERIES 
Characteristic RRIM 2004 RRIM 2005 
Yield for first two years 5 5 
Resistance to wind damage 4 4 
Vigour at opening 4 4 
Virgin bark at opening 4 4 
5= very good; 4 = good; 3 = average; 2=below average; 1=poor; 
TABLE 2.16 DISEASE SEVERITY OF GROUP 2A LATEX CLONES OF RRIM 2000 SERIES 
IN SMALL SCALE CLONE TRIALS 
Characteristic RRIM 2004 RRIM 2005 
Oidium M L 
Colletotrichum L S 
Corynespora L N 
N = Nil L = Light M = Moderate S = Severe 
Group 2B 
Group 2B consists of newly released clones, which are promising in the preliminary 
trials. These clones are selected based on five years yield data and other secondary 
characteristics from trials in limited scale such as SSCT. The performances of these 
clones in different micro-climates, soils and environments are not yet available. Area 
of one hectare or less should be planted with Group 1 clones or together with a basket 
of clones with not more than 20% of Group 2B which comprises 10 latex timber clones 
and 14 latex clones. 
38 
Latex Timber Clones 
The latex timber clones are RRIM 2008, RRIM 2014, RRIM 2020, RRIM 2023, RRIM 
2024, RRIM 2025, RRIM 2026, RRIM 2027, RRIM 2028 and RRIM 2033. The three 
year mean yields of RRIM 2008, RRIM 2014 and RRIM 2020 in LSCT were generally 
low with 1030 kg/ha/yr, 1380 kg/ha/yr and 1650 kg/ha/yr, respectively (Table 2.17). Yield 
data from the other latex timber clones in Group 2B are still not available. The mean 
yields of these clones were therefore extrapolated from the SSCT. The five year mean 
yields ranged from 2007 kg/ha/year for RRIM 2014 to 3040 kg/ha/year for RRIM 2027 
(7ab/e2.78). 
TABLE 2.17 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX-
TIMBER CLONES IN THE LARGE SCALE CLONE TRIALS 
Planting 
material 
Year of tapping Mean 1 2 3 
g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr g/t/t kg/ha/yr 
RRIM 2008 28.98 786 32.79 1082 36.79 1236 36.52 1034 
RRIM 2014 19.01 720 34.28 1526 41.84 1886 39.08 1377 
RRIM 2020 36.33 1083 46.92 1796 51.30 2057 44.85 1645 
Tapping system: !4S d/3 6d/7 
Average of two trials 
TABLE 2.18 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX-
TIMBER CLONES IN THE SMALL SCALE CLONE TRIALS* 
Planting material 
Year of tapping 
Mean 
1 2 3 4 5 
RRIM 2023 1989 2976 3480 2825 2848 2822 
RRIM 2024 1509 2802 2828 3482 3158 2685 
RRIM 2025 1921 2915 3174 2793 2967 2700 
RRIM 2026 1450 2075 2172 3118 2410 2204 
RRIM 2027 2381 2447 3349 3526 3477 3036 
RRIM 2028 1695 1851 2836 2577 3201 2432 
RRIM 2033 1442 1486 2402 2930 2306 2114 
* Extrapolated yield from Small Scale Clone Trials (SSCT) 
39 
All the clones showed good secondary characteristics and the various disease 
severity on the clones ranged from moderate to no infection (Tables 2.19 and 2.20). 
Only RRIM 2026 showed severe infection of Colletotrichum. The girth increment before 
tapping and during tapping of these clones ranged from 8.5-10.7 cm/year and 2.5-7.6 
cm/year respectively. The timber production for these clones ranged from 0.60 to 1.87 
m3/tree at the age of 14 to 16 years old in the SSCT. Whereas, the bole volume of these 
clones ranged from 0.20 to 0.66 m3/tree (Table 2.21) 
TABLE 2.19 SOME IMPORTANT CHARACTERISTICS OF GROUP 2B RRIM 2000 SERIES 
LATEX-TIMBER CLONES 
Characteristic RRIM 2008 
RRIM 
2014 
RRIM 
2020 
RRIM 
2023 
RRIM 
2024 
RRIM 
2025 
RRIM 
2026 
RRIM 
2027 
RRIM 
2028 
RRIM 
2033 
Yield for first 
two years 5 5 4 5 5 5 5 5 5 5 
Resistance to 
wind damage 4 4 4 4 4 4 4 4 4 4 
Vigour at 
opening 5 4 4 5 5 5 5 5 5 5 
Virgin bark at 
opening 4 4 4 4 4 5 4 5 4 4 
5= very good; 4 = good; 3 = average; 2=below average; 1=poor 
TABLE 2.20 DISEASE SEVERITY OF GROUP 2B RRIM 2000 SERIES LATEX-TIMBER 
CLONES IN MONITORED DEVELOPMENT PROJECTS 
Characteristic RRIM 2008 
RRIM 
2014 
RRIM 
2020 
RRIM 
2023 
RRIM 
2024 
RRIM 
2025 
RRIM 
2026 
RRIM 
2027 
Pink disease (incidence) L N L N N N N N 
Oidium M M M L L L M VL 
Colletotrichum M L M M M M S VL 
Corynespora L N L N N N N N 
Phytopthora N N S N N N N N 
N = Nil VL = Very light L = Light M = Moderate S = Severe 
40 
TABLE 2.21 ESTIMATED WOOD VOLUME FOR GROUP 2B LATEX-TIMBER CLONES* 
Planting material Age (years) 
Clear bole volume 
(m3/tree) 
Canopy wood 
volume (m3/tree) 
Total wood volume 
(m'/tree) 
RRIM 2008 14 0.33 0.99 1.32 
RRIM 2014 14 0.53 0.80 1.33 
RRIM 2020 14 0.36 0.64 1.00 
RRIM 2023 14 0.35 0.46 0.81 
RRIM 2024 14 0.52 0.74 1.26 
RRIM 2025 14 0.63 1.20 1.87 
RRIM 2026 14 0.66 0.45 1.11 
RRIM 2027 16 0.60 0.70 1.30 
RRIM 2028 16 0.42 0.21 0.63 
RRIM 2033 15 0.49 0.37 0.86 
* Estimated wood volume from Small Scale Clone Trials (SSCT) 
Latex Clones 
The clones are RRIM 2003, RRIM 2006, RRIM 2010, RRIM 2011, RRIM 2012, RRIM 
2013, RRIM 2017, RRIM 2018, RRIM 2021 and RRIM 2022, RRIM 2029, RRIM 2030, 
RRIM 2031, RRIM 2032. 
The five-year mean yields of the RRIM 2000 series latex clones extrapolated from the 
mean yields in g/t/t from the SSCT ranged from 1901 kg/ha/year for RRIM 2021 to 
2548 kg/ha/year for RRIM 2003 (Table 2.22). These clones are being tested in LSCT 
in different environments. However, the three year mean yields of RRIM 2003, RRIM 
2006, RRIM 2010, RRIM 2011, RRIM 2012, RRIM 2013, RRIM 2017, RRIM 2018, RRIM 
2021 are relatively low ranging from 1040 to 1610 kg/ha/yr (Table 2.23). All the clones 
showed good secondary characteristics and the various disease severity on the clones 
ranged from moderate to no infection (Tables 2.24 and 2.25). 
41 
TABLE 2.22 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES 
LATEX CLONES IN THE SMALL SCALE CLONE TRIALS* 
Planting material 
Year of tapping 
Mean 
1 2 3 4 5 
RRIM 2029 1772 2387 2911 2841 2767 2535 
RRIM 2030 1619 1732 2800 2553 2673 2275 
RRIM 2031 1901 2345 2568 2698 2617 2425 
RRIM 2032 1996 1835 2598 2235 2428 2218 
* Extrapolated yield from Small Scale Clone Trials (SSCT) 
TABLE 2.23 MEAN YIELD (KG/HA/YEAR) OF GROUP 2B RRIM 2000 SERIES LATEX 
CLONES IN THE LARGE SCALE CLONE TRIALS 
Planting material 
Year of tapping Mean 1 2 3 
g/t/t kg/ha/ yr g/t/t 
kg/ha/ 
yr g/t/t kg/ha/yr g/t/t 
kg/ha/ 
y 
RRIM 2003 44.23 1035 57.24 1662 50.50 1732 53.99 1476 
RRIM 2010 40.04 624 49.20 1227 44.02 1303 44.42 1051 
RRIM 2011 42.91 1402 39.51 1598 39.35 1634 40.59 1544 
RRIM 2012 45.61 1184 47.06 1607 57.04 2048 50.02 1613 
RRIM 2013 28.38 606 36.55 1226 37.85 1379 34.26 1070 
RRIM 2017 33.48 753 36.21 1170 33.01 1189 34.23 1037 
RRIM 2018 47.13 902 51.06 1453 51.76 1657 49.98 1337 
RRIM 2021 40.06 1286 43.99 1621 40.39 1574 41.48 1493 
Tapping system: V2S d/3 6d/7 
Average of two trials 
TABLE 2.24 SOME IMPORTANT CHARACTERISTICS OF RECOMMENDED 
GROUP 2B RRIM 2000 SERIES LATEX CLONES 
Characteristic RRIM 2003 
RRIM 
2010 
RRIM 
2011 
RRIM 
2012 
RRIM 
2013 
RRIM 
2017 
RRIM 
2018 
RRIM 
2021 
Yield for first two years 5 5 5 5 5 5 5 5 
Resistance to wind 
damage 4 4 4 4 4 4 4 4 
Vigour at opening 5 4 4 4 3 4 4 4 
Virgin bark at opening 4 4 4 4 4 4 4 4 
5= very good 4 = good 3 = average 2=below average 1=poor NA=not available 
42 
TABLE 2.25 DISEASE SEVERITY OF GROUP 2B RRIM 2000 SERIES LATEX CLONES IN 
SMALL SCALE CLONE TRIALS 
Characteristic RRIM 2003 
RRIM 
2007 
RRIM 
2010 
RRIM 
2011 
RRIM 
2012 
RRIM 
2013 
RRIM 
2017 
RRIM 
2018 
RRIM 
2021 
Oidium M L L M M L L M L 
Colletotrichum M M L L M L L M M 
Corynespora N L N L L L L N N 
N = Nil VL = Very light L = Light M = Moderate S = Severe NA = Not available 
SEEDLINGS 
The planting materials from seedlings should only be obtained from recommended 
seed gardens such as PBIG/GG 6, 7 and 8. Only healthy seedlings with good growth 
form should be selected for field establishment. The commercial yield of these planting 
materials is given in Table 2.26. 
TABLE 2.26. COMMERCIAL YIELD IN KG/HA/YEAR OF RECOMMENDED SEEDLINGS 
Planting 
material 
Year of tapping 
Mean 
1 2 3 4 5 6 7 8 9 10 
GG6 620 1010 1330 1490 1520 1510 1620 1640 1580 1690 1401 
GG 7&8 1100 1380 1950 1840 1850 1800 - - - - 1653 
Data from Golden Hope Plantations Bhd. Tapping system: 3/5S 2d/7 
CLONAL SEEDS 
Clonal seeds are rubber seeds collected from trees of a particular clone. The clones 
must be of good progeny and able to produce abundant seeds. They must preferably 
be high yielding and with good characteristics, such as PB 5/51 and RRIM 623. 
Clonal Seed Collection Area 
The development of a good crown is important; to encourage flowering and fruiting. This 
can be achieved by a low planting density. The planting design should preferably be of 
rectangular or avenue system, with a planting design should preferably be rectangular 
or avenue system, with a planting distance of 9 m x 3 m. This gives a density of 360 
43 
points per hectare. The trees are later gradually thinned out to a final stand of 250 per 
hectare. The size of a seed garden depends on the quantity of seeds available at each 
season. It is estimated that between 35,000 and 100,000 seeds can be obtained from 
a hectare annually. Seed gardens must be isolated to prevent pollen from unknown 
materials crossing with those in the garden. This can be achieved by having a seed 
garden situated far away from other rubber areas. Sometimes this is not possible. A 
seed garden can also be set up within a rubber plantation, provided an isolation belt 
of 100 m around it is clearly marked out. Clones planted in the isolation belt must be 
the same as those in the seed garden, but the seeds found in the isolation belt are not 
collected for use as clonal seeds. The shape of the seed garden should preferably be 
square, as it gives a bigger isolated inner area than a rectangular-shaped seed garden 
(Figure 2.6). 
160 ha 
> 
100 m 
I 
100 m 90 ha 100 m 
/ \ 
100 m 
\ I 
500 m 
164 ha 
^100 m 
s 100 m 86 ha 
100 m 
o 
^100 m 
610 m 
Figure 2.6 Schematic shape of seed gardens - square and rectangular (not to scale) 
44 
Arrangement of Clones for the Seed Garden 
A clonal seed garden may contain only clone (monoclone) or several clones (polyclone). 
To encourage cross pollination in a polyclone area, various clones are planted close to 
one another, and arranged in such a manner that an even cross pollination can take 
place. Usually, three to five clones are used (Figures 2.7(i-vi)). 
A A A B B B C C C 
B B B C C C A A A 
C C C A A A B B B 
Repeat 
Repeat 
Repeat 
Repeat Repeat 
i) Three clones A,B,C (each letter = 1 tree) 
A B C D Repeat 
C D A B Repeat 
B C D A Repeat 
D A B C Repeat 
Repeat Repeat 
ii) Four clones A,B,C,D ((each letter = 3 or 4 trees) 
A B C D E Repeat 
C D E A B Repeat 
E A B C D Repeat 
B C D E A Repeat 
D E A B C Repeat 
Repeat Repeat 
iii) Five clones A,B,C,D,E (each letter = 3 or 4 trees) 
45 
A A A A A A A A A A A etc 
B B B B B B B B B B B etc 
C C C C C C C C C C C etc 
Repeat 
iv) Three clones A,B,C ((each letter = 1 tree) 
A A A A A A A A A A A A etc. 
B B B B B B B B B B B B etc. 
C C C C C C C C C C C C etc. 
D D D D D D D D D D D D etc. 
A A A A A A A A A A A A etc. 
C C C C C C C C C C C C etc. 
D D D D D D D D D D D D etc. 
B B B B B B B B B B B B etc. 
A A A A A A A A A A A A etc. 
C C C C C C C C C C C C etc. 
B B B B B B B B B B B B etc. 
D D D D D D D D D D D D etc. 
Repeat 
v) Four clones A,B,C,D (each letter = 1 tree) 
46 
A A A A A A A A A AA etc. 
B B B B B B B B B B B etc. 
C C C C C C C C C C C etc. 
D D D D D D D D D D D etc. 
E E E E E E E E E E E etc. 
B B B B B B B B B B B etc 
D D D D D D D D D D D etc. 
A A A A A A A A A A A etc. 
C C C C C C C C C C Cetc . 
E E E E E E E E E E E etc. 
Repeat 
vi) Five clones A,B,C,D,E (each letter = 1 tree) 
Figure 2.7 Arrangement of clones in seed garden 
If designs as shown in Figures 2.7(i-iii) are used, close supervision must be carried out 
during transplanting, as the clone changes at every point, third point or fourth point. In 
the designs shown in Figures 2.7(iv-vi), only one clone is transplanted for the planting 
row. Perhaps this may reduce inter-tree competition for growth since the same type of 
clone is used along each row and less supervision required during transplanting. But 
this method is less effective in terms of cross pollination. If close supervision can be 
guaranteed during transplanting, designs shown in Figures 2.7(i-iii) are preferred. 
Types of Clonal Seed 
For large-scale planting (Class I), PBIG/GG6 seeds are recommended, and for 
moderate-scale planting (Class II), PBIG/GG7, seeds from approved areas, and seeds 
collected from boundaries between clones are recommended for large and moderate 
scale planting. Currently, clonal seeds are obtainable only from commercial sources, 
such as Sime Darby Berhad. 
47 
Besides clonal materials derived from buddings, as described earlier, clonal 
seeds offer another option of planting material for the plantation industry. However, in 
Malaysia, this type of planting material is limited to the estates sector only. Smallholders 
are prohibited from using them. 
RUBBER SEED AND ITS GERMINATION 
Rubber seed is also a planting material that can develop into a tree. It derives from 
sexual propagation, that is, through the process of pollination. Seeds are said to be 
the basis of all rubber trees. Whatever the material that is finally transplanted into the 
field, it must have started from the seed. Seeds are also raised as stock plants for 
all grafting processes, such as bud-grafting, cleft-grafting, approach-grafting and root/ 
seed-grafting. 
The Seed 
Rubber seed is of the dicotyledon type. The seed coat is semi-hard and has five sides, 
namely the ventral, dorsal, micropyler, frontal and sides (Figure 2.8). A hole known as 
the micropyle can be found at one end of the seed coat, where the micropyler is. It 
is through the micropyle, the radical and plumule appear, when the seed germinates. 
Rubber seed can be considered a vegetable product, because it is edible. It contains 
oil, which can be extracted for commercial use, and the byproduct can be used for 
poultry feed mixture. 
Figure 2.8 Various sizes of rubber seeds from different clones 
48 
Rubber seed comes from the fruit, which is the result of pollination between 
the male and the female flowers. Rubber trees flower normally in March and August. 
Seedfall occurs approximately five months later. To ensure germination, fresh-fallen 
seeds are used, which can easily be recognised from the appearance - shiny, heavy 
and defect-free. The weight of a fresh-fallen seed differs according to its size, which 
again differs according to the clone (clonal characteristic). As a guide, a kilogramme of 
RRIM 623, PB 5/51 and GT 1 seeds consists of 200, 300 and 340 seeds respectively. 
Rubber seed comes under the group of seeds with high water content and is therefore 
easily destroyed at very low or very high temperature. It has a short viability period and 
declines very dramatically, when exposed to direct sunlight (Table 2.27). 
TABLE 2.27 PERCENTAGE GERMINATION OF RUBBER SEEDS 
EXPOSED TO SUNLIGHT 
Length of exposure to sunlight (day) Percentage germination 
1 95 
2 68 
3 9 
4 1 
5 0 
Source: Prang Besar Research Station (PBRS) 
Therefore, seeds must be collected daily or alternate daily and setfor germination 
immediately. If this is not possible, the seeds must be spread under shade in one layer 
on the ground, or because of their seasonal nature, they can be packed in 10% damp 
sawdust or 20% damp powdered charcoal, in small perforated polybags and kept in a 
cold room at 7-10 °C. In this way, the seeds can be kept for three months. 
Stock plants are known to influence the performance of the scion, in terms 
of growth and later, in yield. Therefore, it is advisable to use seeds from (arranged 
according to their preference) PB 5/51, RRIM 623, GT 1, RRIM 712, RRIM 605, PB 217 
and PB 235 clones for such purpose (Tables 2.28 and 2.29). 
TABLE 2.28 EFFECT OF SIX ROOTSTOCKS ON GROWTH OF SCION 
Type of rootstock Girth at opening (cm) Tappability (%) 
RRIM 600 49.2 46.2 
RRIM 501 49.1 43.4 
RRIM 623 51.3 57.3 
Tjirl 50.8 56.6 
PB 5/51 53.2 67.8 
Unselected seedlings 51.7 63.4 
49 
TABLE 2.29 TEN YEARS SCION YIELD 
Combination 
Yield (kg/ha/year) Mean 
rootstock 
effect 
RRIM 
600 
48E/ 
130 PB 5/51 
RRIM 
628 SG170 
RRIC 
52 
Rootstock 
PB 5/51 2,512 2,469 1,839 1,747 1,716 983 1878 
RRIM 623 2,119 2,094 1,870 1,637 1,604 807 1,688 
Unselected 
Seedlings 2,155 2,101 1,640 1,503 1,503 785 1,617 
Tjirl 2,317 2,004 1,566 1,630 1,292 859 1,611 
RRIM 501 1,953 2,024 1,480 1,528 1,582 814 1,563 
RRIM 600 2,097 1,600 1,387 1,414 1,366 892 1,459 
Mean scion effect 2,192 2,049 1,630 1,577 1,513 857 1,636 
Seed Germination 
Seeds that are to be planted out should first go through the germination process. 
For large quantity of seeds, it is economical to use the germination bed. This can be 
done by constructing a raised bed of loose soil, river sand or well-weathered sawdust 
15 cm high, 100 cm wide and the length depending on the number of seeds to be set; 
each square metre of germination bed surface can accommodate approximately 1,000 
seeds. A raised partial shade of 1 m high should be erected over the bed to prevent 
direct sunlight. The seeds are spread over the bed in one layer, close together. They 
are then pressed into the germination bed surface. The seeds are covered by putting 
a layer of loose soil, river sand or well-weathered sawdust to the thickness of about 
1.5 cm. The seeds are watered twice daily. Germination occurs on the tenth day, but 
peak germination is between two and three weeks. 
The best time to transplant germinated seeds is when the radicals appear 
and the plumules are just visible above the bed surface. If transplanting is delayed, 
the radicals and plumules grow too long and much damage can occur. This should 
be avoided by timing the nursery operation well. The germinated seeds are carefully 
levered out of the bed with the help of a small piece of flat-end wood or bamboo. As 
the cotyledons provide early food to the sprouting plumules/radicals, care should be 
taken not to detach the seeds from them. The germinated seeds must be transplanted 
immediately (Figure 2.9) 
50 
a) Fresh-fallen rubber seeds (b) Setting seeds on sawdust-mounted 
germination bed 
(c) Various stages of germination of rubber seed (d) Germinating seeds 
Figure 2.9 Germinating rubber seeds 
NURSERIES AND THE PRODUCTION OF PLANTING MATERIALS 
A nursery is a special area, where planting materials are raised for transplanting into the 
field. A rubber nursery can be considered as a factory producing planting materials. 
Objectives of Setting Up a Nursery 
The objectives of establishing a rubber nursery are to: 
• nurture and raise high quality planting materials in large scale 
• prepare advance-aged planting materials, if necessary 
51 
• ensure that planting materials transplanted into the field achieve high initial 
establishment success 
• reduce costs of plantation development by reducing failures at the initial stage 
• obtain plants in the field reaching early maturity 
Choice of Nursery Site 
Rubber nursery is divided into two categories - ground nursery and polybag nursery. In 
a ground nursery, the plants are planted on the ground, whereas in a polybag nursery, 
the plants are planted in the polybags arranged in rows in a nursery. In selecting a 
nursery site, the following factors must be considered. 
• The soil must be well structured and textured (for ground nursery only) 
• There must be a good source of water supply 
• The land must be flat or slightly sloping 
• Water table should be below 75 cm from the surface (for ground nursery only) 
• The land should be an open area (not under shade) 
• It must be free from root disease source 
• Preferably having good infrastructure 
Type of Nursery 
There are no less than eleven types of nursery producing various types of planting 
materials. The commonly practised ones are: 
• Budstick multiplication nursery (ground nursery) 
• Budded stump nursery (ground nursery) 
• Budded stump in polybag nursery 
• Young budding nursery 
• High budding nursery 
• Core stump nursery (ground nursery) 
Establishment of Nursery 
A nursery site must be cleared and cleaned of all vegetations. This includes removal of 
tree stumps and roots. For a ground nursery, the land must be ploughed twice, followed 
by harrowing and rotovation or harrowing once. Basal fertiliser of 250 kg/ha ground 
magnesium limestone is broadcast just before the second ploughing and 625 kg/ha of 
rock phosphate, such as Christmas Island Rock Phosphate (CIRP) just before rotovation. 
For a polybag nursery, tilling of land is unnecessary. Instead, filled polybags are laid 
52 
in straight double rows as soon as the site is lined and cleared (Figure 2.10). For 
large nurseries, watering system such as the sprinkler or the Sumi Sansui be 
installed. Planting distances for the various nurseries described above are shown 
in Table 2.30. 
(c) Maintenance of seedlings in polybag (d) Polybag nursery 
Figure 2.10 Establishment of polybag nursery 
53 
TABLE 2.30 SUGGESTED PLANTING DISTANCES IN RUBBER NURSERIES 
Type of nursery Planting distance (cm) 
Approximate density 
per hectare 
Budstick multiplication 120 x 120 6.944 
Budded stumps 60 x 15 111,111 
Budded stump in polybag 96 x 18* 115,740 
Young budding 96 x 18* 115,740 
High budding 180 x 25* 44,444 
Core stump 180x70 7,936 
"Double rows 
Budstick multiplication nursery. In a budstick multiplication nursery, planting 
holes of 45 cm x 45 cm x 45 cm size are dug at each marked out planting point. Polybag 
buddings (budded stumps in polybags or young buddings in polybags) are used as 
starting materials. Although other materials can be used, budded stumps in polybags 
and young buddings are able to produce budsticks at a faster rate. Polybag buddings 
are then transplanted into the prepared planting holes. 
Budded stump nursery. A budded stump nursery, which is also a ground 
nursery has planting rows marked at intervals of 60 cm, along two opposite boundaries 
(Figure 2.11). Lining ropes marked with a planting distance of 15 cm are stretched 
along planting rows already marked. A rounded sharp-pointed stick is used to punch 
a cavity of 8 cm deep (depth may vary according to the length of the radical of the 
germinated seed to be transplanted) in the soil at every point marked along the lining 
rope. Germinated seeds are then placed in the carvities with the radicals downward. 
The cavities are refilled by gently pressing the soil around the seeds. Seeds with twisted 
radicals should not be transplanted. The seeds must not be detached from the radicals 
during the transplanting operation. 
Figure 2.11 Ground nursery 
54 
Budded s tumps in polybags nursery. Polybags of 18 cm x 38 cm layflat 
dimensions are filled with suitable soil, which has been mixed with rock phosphate at 
56 g per bag of soil. Planting rows are marked at intervals of 96 cm along two opposite 
boundaries of the nursery. A40-cm strip of the soil along each planting row is roughly 
levelled to facilitate proper placement of the polybags. At each planting row (where 
the levelled strip is) two rows of filled polybags are placed. The polybags can be kept 
upright by slightly mounting the soil at the base or by stretching galvanised wires or 
by fixing wooden beroties along the sides. To facilitate transplanting, the soil in the 
polybags is first watered. A round sharp-end hardwood stick, the size of which should 
be slightly larger than the tap root of the budded stump to be transplanted, is used. 
The tap roots are planted with their tips 5 cm above the base of the polybags. Budded 
stumps with longer roots are pruned off to fit into the polybags. Budded stumps with 
twisted or very short tap roots are discarded. After measuring the tap root of the budded 
stump with the above stick, it is pierced into the soil to the required depth. The tap root 
of the budded stump and is then placed into the cavity. Water is again poured into the 
bag to close up the cavity and to prevent air pocket around the tap root (Figure 2.12). 
(a) Extracting budded stump (b) Selection of budded (c) Prunning of tap root 
stump 
(d) Placing tap root in (e) Arranging polybags in two (f) Budded stump with new 
polybag rows shoot 
Figure 2.12 Transplanting budded stumps into polybags 
55 
Young budding nursery. Preparation and laying of polybags in a young 
budding nursery are the same as for the budded stumps in polybags nursery. But in 
this type of nursery, germinated seeds are transplanted into the polybags, to be raised 
as seedling stocks for subsequent budding. Using a flat sharp-end piece of wood or 
bamboo, a cavity is made in the soil in the polybag, large and deep enough to fit in 
the radical and the seed. The germinated seed is placed in the cavity with the radical 
downward. The cavity is refilled with soil and carefully pressed. The seed must be fully 
covered with soil. 
High budding nursery. Preparation and laying of the polybags for a high 
budding nursery are the same as described earlier, except that polybags are bigger, 
with layflat dimensions of 25 cm x 50 cm and the inter-row distance is 180 centimetres. 
Germinated high quality clonal seeds such as PBIG/GG6 or PBIG/GG7 are transplanted 
into the polybags. The technique of transplanting is the same as described earlier. 
They are raised as stock plants for subsequent budding. 
Core s tump nursery. In the preparation of a core stump nursery, a trench of 
30 cm wide and 45 cm deep is dug along each planting row. Polybag young buddings 
are placed in the trench at 45 cm apart. The trench is refilled with soil, incorporating 
56 g of rock phosphate per point (Figure 2.13). 
(a) Preparing trenches for polybag buddings 
(b) Transplanting polybag buddings into prepared 
trenches 
Figure 2.13 Preparing core stump nursery 
56 
Maintenance of Nursery 
Watering of the plants is essential, especially for the polybag nurseries. Using the 
sprinkler or Sumi Sansui system, water is released twice daily for a total of two hours. 
Weeds are regularly controlled, initially by manual weeding. Herbicides are only used 
when the plants are at least two months old, and when the leaves have hardened. 
Spraying of Paracol at 2 litres in 450 litres of water per hectare should give satisfactory 
control of nursery weeds. Thinning out runts, genetic yellows, defective and chronically 
diseased plants are carried out from time to time. Manuring is done following specific 
schedules according to the type of nursery. 
Budstick multiplication nursery. Fertiliser is applied according to schedule 
shown in Table 2.31. The scion shoot is allowed to grow until 60-90 cm of brown bark 
has been formed. The scion stem is then cut-back at a height of 60 or 90 cm, just 
above a whorl of buds. Several side shoots will emerge, but only four or five vigorous 
ones are retained to form branches. Budsticks can be obtained by pruning back; as 
the snags left behind will again regenerate more shoots. Budsticks with green to dark 
green bark are normally used. After repeated pruning, the plant gives a bush-like crown 
formation. This is why this nursery is sometimes known as the bush nursery. Each 
budstick multiplication nursery should be productive for at least ten years. 
TABLE 2.31 MANURING SCHEDULE FOR BUDSTICK MULTIPLICATION 
NURSERY 
Time of 
(month after planting) Types of fertiliser 
Dosage 
(g per plant) 
2 Equivalent Mixture Magnesium X 42 
3 Equivalent Mixture Magnesium X 42 
4 Equivalent Mixture Magnesium X 42 
5 Equivalent Mixture Magnesium X 42 
7 Equivalent Mixture Magnesium X 42 
g Equivalent Mixture Magnesium X 42 
11 Equivalent Mixture Magnesium X 42 
13 Equivalent Mixture Magnesium X 42 
15 Equivalent Mixture Magnesium X 42 
After fifteen months and onwards, fertiliser application is continued after each harvesting of budsticks. 
As soon as the budsticks are harvested, the leaf petioles are removed by 
pruning to avoid loss of water in the wood. Both the scale and the axillary buds on the 
budstick are usable. To facilitate packing, budsticks are cut to 30 cm length and usually 
57 
contain an average of two buds per stick. If the budsticks are to be kept overnight 
and longer, 1 cm at both ends must be sealed in molten wax to slow down the drying 
process. Budsticks are packed in cardboard or plywood boxes, interlayered by 10% 
damp sawdust. They should be kept in a cool place, but not exceeding a week. Where 
possible, budsticks must be used fresh (Figure 2.14). 
(a) Scion stem ready for cutback (b) Advanced stage of green budstick nursery 
(c) Trimmed budsticks (d) Dipping budstick ends in molten wax 
(e) Packing budsticks in cardboard box (f) Packed budsticks ready for transportation 
Figure 2.14 Producing green budsticks 
58 
Budded s tump nursery. Fertiliser is applied according to schedule (Table 
2.32). The seedling stocks are green-budded at five to six months old. After three 
weeks, the successful budded plants are extracted. The stem of each plant is cut-back 
at 5 cm from the bud eye, and the cut end sealed in molten wax. The tap root is pruned 
off to 30-45 cm, while the side roots are all pruned off flush. The tap root is then dipped 
in IBA root stimulant formulation. If the budded stumps are to be transported to a long 
distance, they should be packed in 10% damped sawdust, at fifty stumps per bundle 
(Figure 2.15). 
TABLE 2.32 MANURING SCHEDULE FOR BUDDED STUMP NURSERY 
Time of application 
(month after planting) Types of fertiliser 
Dosage 
(g per plant) 
2 Equivalent Mixture Magnesium X 60 
3 Equivalent Mixture Magnesium X 60 
4 Equivalent Mixture Magnesium X 60 
5 Equivalent Mixture Magnesium X 60 
Budded s tumps in polybags nursery. Fertiliser in applied according to schedule 
(Table 2.33). The scion shoot is allowed to grow until two whorls of hardened leaves 
have been formed. The material is then ready for transplanting (Figure 2.16). 
TABLE 2.33 MANURING SCHEDULE FOR BUDDED STUMP 
IN POLYBAGS NURSERY 
Time of application 
(month after planting) Types of fertiliser 
Dosage 
(g per plant) 
1 Equivalent Mixture Magnesium X 28 
3 Equivalent Mixture Magnesium X 28 
Young budding nursery. Fertiliser is given according to schedule (Table 
2.34). The seedling stocks are young-budded at ten to twelve weeks old. The stocks 
of successful buddings are cut-back. The scion shoots are allowed to grow until two 
whorls or hardened leaves have been formed. By this time, the tap roots may have 
penetrated the ground, and may require tailing. Two weeks before transplanting, the 
polybags are slightly lifted to severe the roots ground level. Watering must be continued 
until the materials are taken out of the nursery (Figure 2.17). 
59 
60 
Figure 2.16 Polybags budded stump nursery where the scion shoots have 
emerged to two hardened whorls of leaves and ready for transplanting 
TABLE 2.34 MANURING SCHEDULE FOR YOUNG BUDDING NURSERY 
Time of application Type and dosage of fertiliser 
After transplantina 
aerminated seeds in 
oolvbaas 
1-8 weeks (twice weekly) 
Spraying of foliar feed and fungicides mixture of 
Bayfolan = 15 ml + 
Dithane M-45 = 10 g + 
Daconil - 12 g + 
Water = 4.5 litres 
2-6 weeks (weekly) NPKMg @ 15:15:6.4 with soluble phosphate 56 g + 4.5 litres water = 40 
- 60 ml per polybag 
Stock plants at one whorl 
Staae 
After cut-back of stock 
Plant 
2 weeks and onwards 
(twice weekly) 
Or* 
Slow release fertiliser such as Nurseryace or Kokei = 7 g per polybag 
Spraying of foliar feed and fungicides mixture of 
Bayfolan = 15ml + 
Dithane M-45 = 10 g + 
Daconil = 12 g + 
Water = 4.5 litres 
4 weeks and onwards 
(weekly) 
Scion reaches copper-
bronze leaflet staae 
NPKMg @ 15:15:6.4 with soluble phosphate 56 g + 4.5 litres water = 40-
60 ml per polybag 
Or* 
Slow release fertiliser such as Nurseryace or Kokei = 7 g per polybag 
*When there is shortage of labour 
61 
(a) Spraying of foliar fertiliser and 
fungicides mixture 
(c) Applying slow release fertiliser 
(e) Young budding plants of two 
whorls ready for transplanting 
(b) Applying slurry fertiliser 
(d) Seedling stocks ready 
for young budding 
(f) Feeder root mass found on young 
budding materials which can assist in 
their early establishment in the field 
Figure 2.17 Manuring young budding materials 
62 
High budding nursery. At the moment, the fertiliser schedule recommended 
for young budding nursery is also used for the high budding nursery. The stock plants are 
green-budded at five to six months old. Budding is done at a height of 100 centimetres. 
Four weeks after budding, the top portion of successful budded plants are cut-back and 
the scions are allowed to grow to one or two hardened whorls of leaves for transplanting. 
Prior to that, tailing is also done as described earlier. Again, watering must be continued 
until the materials are taken out of the nursery. 
High budding materials have two productive stem components. Upon maturity, 
the stems or trunks will have 100 cm of good clonal seedling materials at the lower 
part, and 200 cm of budded materials above them. This allows for early tapping, as, by 
nature the seedling tree tapers upwards and the bottom portion reaches maturity earlier 
(Figure 2.18). 
Core s tump nursery. Fertiliser is applied according to schedule (Table 2.35). 
As the scion shoots grow, side branches may also appear, which must be pruned off. 
This is to obtain clean stems of 210-240 cm for exploitation later on. Diseases and 
pests are also controlled when necessary. The plants can be transplanted at 12-18 
months old. The stems are cut-back at a height of 240 cm, just above a whorl of buds. 
The cut ends are treated with suitable wound dressing. The stems are then painted 
white using dehydrated lime (1 kg + 1 litre water) to prevent scorching of the bark. At the 
same time, the tap roots are pruned off (tailing) to 45-60 cm, with a root pruner (oil palm 
fruit harvesting chisel). The plants, now called core stumps (maxi stumped buddings 
with soil cores), can be extracted for field transplanting, when the topmost buds have 
broken (bud-break stage). This takes approximately 10-14 days after cut-back. The 
stumps can also be left in the nursery much longer until all the leaves at the top whorl 
have hardened, thus, giving flexibility to the time of transplanting such materials. Care 
must be taken to prevent the soil core surrounding the roots from breaking up. These 
are categorised as advance-aged planting materials, in view their large stem size. They 
are expected to be brought into tapping much earlier (Figure 2.19). 
TABLE 2.35 MANURING SCHEDULE FOR CORE STUMP NURSERY 
Time of application Type of fertiliser Dosage per plant 
Immediately after planting Nursery ace* 14 g (2 pellets) 
Every six months Nurseryace* 14 g (2 pellets) 
"Kokei can also used, but every three months. The fertiliser is slightly buried in the soil, very close to the 
plant. 
63 
(a) Successfully high budding (b) High budding at one whorl stage 
(a) Cutting-back scion stem to height of 240 cm (b) Manual extraction of white-
and apply wound dressing to the cut end washed core stumps 
(c) Extracting core stumps with the help of an (d) Core stumps at one whorl stage 
excavator at bud-break stage after planting 
(e) Core stumps material planted in the field 
Figure 2.19 Production of core stumps 
65 
ROOT INDUCTION 
Growth of rubber tree depends mainly on its roots, especially the side ones, which bear 
the feeding roots. When preparing budded stumps for transplanting, all the side roots 
are normally pruned off flush with the tap roots to facilitate planting. Therefore, early 
and fast re-emergence of the side roots in abundant quantity after planting is most 
important, to assist in the sprouting of the scions, and subsequently in the growth of 
the plants (Table 2.36). With good root system, the plants are able to uptake water and 
nutrient solution efficiently. This indirectly influences the overall growth of the tree. By 
using plant growth regulators, such as IBA (Indolebutyric acid), the above objectives 
can be achieved (Figure 2.20). 
TABLE 2.36. EFFECT OF IBA 2000 ROOT PRODUCTION OF BUDDED STUMPS OF 
DIFFERENT GIRTH SIZES 
Girth diameter Treatment 
Mean dry weight of roots (g) 
(cm) 2 weeks 4 weeks 8 weeks 
1.25 Control 0.23(100) 0.27(100) 0.48(100) 
IBA (2000 ppm) 0.53(230) 0.75(278) 1.42(296) 
2.50 Control 0.27(100) 0.36(100) 0.42(100) 
IBA (2000 ppm) 0.30(111) 0.72(200) 1.57(374) 
3.75 Control 0.00(100) 0.29(100) 0.47(100) 
IBA (2000 ppm) 0.13(130) 0.74(255) 1.36(289) 
5.00 Control - 0.31(100) 0.55(100) 
IBA (2000 ppm) 
- 0.83(268) 1.64(298) 
The clone budded was RRIM 600 
Figures within brackets indicate percentage response of control 
IBA Formulation 
To prepare the formulation, dilute 2 g of IBA (product of Sigma Chemicals, USA) in 10 ml 
of absolute alcohol. Mix 1 kg of kaolin powder with 250 ml of water and 750 ml of 50% 
(commercial) alcohol, separately. Then mix all the ingredients thoroughly in a blender; 
and dry the mixture in an oven overnight at 70 °C until it turns to powder. The powder 
can be kept for a long period, provided it is not exposed to light. In this formulation, the 
quantity of IBA in kaolin is 2,000 parts per million (ppm). 
66 
(a) Without IBA 2000 treatment 
(b) With IBA 2000 treatment 
Figure 2.20 Effect of IBA on root development of budded stumps 
Application Method 
The IBA formulation must be diluted before use. To dilute it, dissolve 1 kg of the powder 
in 1,050 ml of water and 750 ml of 50% alcohol to obtain a solution of 1:1.8 powder/ 
solution. Pour the mixture into a special cylinder. Dip the tap root of the budded 
stump into the cylinder containing the mixture, and allow it to dry under shade before 
transplanting or packing. The remainder of the diluted mixture, if any, can be kept for 
use later, but not exceeding three months. 
67 
The oldest rubber tree growing in Kuala Kangsar, Perak. This specimen 
came from the original batch of seedlings from Brazil. 
68 
CHAPTER 3 
SOILS AND LAND PREPARATION 
Soil is the uppermost layer of the earth crust, which is formed by partial or complete 
disintegration or decomposition of parent materials, subject to various degrees of 
weathering. The composition of soil is 45% mineral particles, 25% soil air, 25% water 
and 5% organic material. Although there are plants that can survive without soil, the 
majority of them, including rubber, need soil as a medium for growth. 
Factors Influencing Soil Formation 
The formation of soil depends on factors such as parent materials, vegetation, climate, 
topography and time. This means that the principle of soil formation is the action of 
climate on parent materials and vegetation, modified by topography, over a period of 
time. 
The interaction of similar weathering process with different parent materials 
produces different kinds of soil. It is also true that the development of the same parent 
materials under different climatic regimes and vegetation can also result in the formation 
of different soils. Topography determines the ease of rain water penetration into the 
ground and the drainage of water from specific areas. Topography has therefore a 
modifying influence on the degree of weathering and the soil that is formed. 
As the climate and vegetation do not vary very much between north and south 
of the Peninsular, Sabah and Sarawak, the type of soils formed in Malaysia depends 
mainly on the parent materials and topography. 
Parent Materials 
Parent materials are the main factor in soil formation. In fact, they are the basis of soil 
type. They are mostly made up of various types of rocks, as listed below. 
Intrusive rock - granite, granodiorite, gabbro and serpentinite 
Extrusive rock - rhyolite or dacite, andesite and basalt 
Sedimentary rock - conglomerate 
Hybrid rock - carbonaceous shale 
Chemical origin rock - limestone and quartzite 
Metamorphic rock - slate, phyllite and schist 
69 
Weathering and Soil Formation 
Soils are formed from mixtures of fragmented and partially or fully weathered rocks, 
mineral and organic matter in varying proportions and are dynamic in character. They 
reach an equilibrium stage with the environment after a long period of exposure to a 
given state of conditions. The fragmentation of rocks and parent materials is the result 
of climatic forces. Weathering is either chemical or physical. In physical weathering, 
the parent material is broken down by environmental conditions, such as temperature, 
running water, and action of plant roots. Chemical weathering causes disintegration or 
changes of substances present in the parent material, often the result of biological and 
chemical activities. 
Soil Profile 
The degree of interaction of physical and chemical processes influences soil genesis 
in two steps - accumulation of materials and differentiation of horizons in a profile. In 
creating a particular profile, oxidation may cause discolouration of fragments of the 
parent rock to a considerable depth. Clay minerals and iron compounds leached from 
the upper part of the profile may be concentrated lower down the profile. Such distinctive 
successive layers approximately parallel to the ground surface and produced by soil-
forming processes are called horizons, which characterise the soil. By colour, chemical 
tests, grain-size analysis and other criteria, soil profiles can be sub-divided into many 
horizons and sub-horizons, and by comparison of their nature and intensity, the soil can 
be classified. Thus, a typical profile usually consists of five main horizons, from the 
surface down to the unaltered rock (Figure 3.1). 
f"u^?^T'£J'*j;|pjFjCjBBE*»v" 0 F r e s n o r partially decomposed organic matter 
• A Abundant roots and accumulation of humus in a primarily mineral 
horizon, clay, carbonates and iron leached to deeper horizons 
- B Finely divided humus and clay accumulated from the A horizon 
B Accumulated clay, iron oxide and some humus, prismatic or blocky 
structure 
- C Slightly altered parent material 
R Unaltered rock material 
Figure 3.1 Atypical soil profile 
70 
Process of Soil Formation 
Not all the five main horizons are seen in a single soil profile. Depending on the degree 
of development, three or sometimes only two horizons are present. The differentiation 
of horizons is determined by the combination and balance of the physical processes, 
which in turn, governed by the relative strength of the five main soil formation factors. 
The relative importance of each process is reflected in the final character of the soil. 
As the basic physical and chemical processes are much controlled by the main 
soil formation factors, especially that of climate on a regional basis, different sets of 
combinations of these processes are specific to different geographical and climatic 
zones. The more important soil-forming processes influencing the development of soils 
in Peninsular Malaysia are described below. 
Latosolisation. This is the most common process. Under abundant rainfall 
and high temperatures of the tropics, there are great weathering forces. Hydrolysis 
and oxidation are rapid and the soluble bases of calcium, potassium, magnesium and 
sodium are leached away quickly. Due to the mobility of these cations, the pH is lowered 
and this low acidity condition is worsened by the rapid decay of the organic residues and 
the immediate release of the bases in organic combination. As a result, the solubility 
of silica is enhanced, retarding those of iron, manganese and aluminium. With good 
drainage, intense oxidation takes place. As weathering proceeds, the resultant profiles 
are high in sesquioxides and low in silica. The residual and accumulated iron produce 
very deep bright red coloured soil such as the Kuantan, Segamat, Prang and Langkawi 
series. 
Laterisation. As weathering processes occur further on the latosol, replacement 
action of silica by hydroxyl groups takes place and hydrated iron and aluminium oxides 
are formed. These oxides called goethite and bauxites are concretionary in nature and 
they constitute laterites or ironstones, which range 1-50 cm in size. These are commonly 
found in many rubber-growing soils of Peninsular Malaysia. Sometimes, such laterites, 
when cemented, form thick, hard and impenetrable ironstone pans, which are common 
in Melaka, Gajah Mati, Tavy and Changloon series. 
Ground water laterisation. At times, ground water laterites can be formed 
on low terrain areas due to fluctuating ground water table. This influences a rapid 
alternating oxidation-reduction action on the lower lying materials such as the parent 
material, resulting in the formation of ground water laterites. This is a notable feature in 
some of the riverine alluvial soils and soils derived from sedimentary materials such as 
the Batu Anam series. 
71 
Podzolisation. This is only confined to soils, such as the Rudua and Rusilia 
series. With high organic cycle, low terrain, which does not drain water quickly, and 
sandy medium, which eases leaching, there is considerable removal of salts and 
carbonates. This is followed by marked release and transfer and redeposition of organic 
humic acids and sesquioxides, especially iron, down the lower lying layers, leaving a 
whitish bleached A2 horizon in the upper 30 cm layer and dark, slightly reddish-brown 
layer of redeposited mixed organic acids and iron oxides in the lower layers. 
Podzolic process . In the higher terrain areas and under abundant rainfall, 
podzolisation process is modified and gives way podzolic influences. Under better 
drained conditions and a more intense weathering process, easily weathered minerals 
are changed to secondary clay, oxides and iron. The bases are lost by leaching 
segregation of insoluble oxides as amorphous materials occur. Clays are formed in 
its place and vertically moved at depths so that a textural B horizon, with bright or 
yellowish-red colour, occurs. Soils with such diagnostic horizons with clay formation, 
movement and accumulation at depths are featured in Rengam, Jerangau, Bungor and 
Munchong series. The textural B horizon is usually thick and as such, these soils are 
very deep, extending up to 150 cm and more. 
Gleization. This process is influenced by a high permanent water table on low 
terrain. There is an excess of soil moisture due to poor drainage, which is either due to 
the soil characteristics or because the soil is situated in low-lying area. As a result, there 
are little alteration processes, and undecomposed organic layer lies on the surface, 
with a lower layer retaining its grey colour due to little alteration in deposited materials. 
This is a feature in Kangkong and Selangor series soils. But, going inwards from the 
coast, where the terrain is higher, fluctuating water table causes alternating dry and wet 
conditions. Oxidation of iron-rich spots takes place, resulting in red, yellow or brown 
streaks of iron mottles in the profiles of Briah and Sitiawan series. 
Soil Colour 
Colour of the soil must be determined when the soil is moist. The colour may be uniform 
or may vary, the most common being bright, dark or mottled, depending on drainage. 
Colour is also determined by the type of minerals present in the soil. For example, red 
shows that there is goethite or hermatite and and black shows there is manganese 
oxide, montmorilonite or organic materials. 
72 
Soil Texture 
Soil texture is a measure of the relative proportions of the various types of soil particles in 
the solid phase of the soil. The particles are graded by their diameter size and a name is 
given for each type. Table 3.1 gives the international particle names and specifications 
of soil texture. 
TABLE 3.1 SOIL FRACTIONS AND THEIR DIAMETER SIZE LIMITS 
Fraction name Diameter size limit (mm) 
Gravel >20 
Coarse sand 2.0-0.2 
Fine sand 0.20-0.02 
Silt 0.02-0.002 
Clay <0.002 
The texture of soil determines whether the soil can retain water and nutrients. 
It is therefore, considered important in terms of soil fertility. Soil texture can be roughly 
estimated by feeling with the fingers. Too much clay or too much sand in the soil is 
undesirable for plant growth, including rubber. Therefore, a right combination of the two 
is needed. Texture depends very much on the parent material. For example, basalt 
produces clay soils, while granite produces sandy clay soils. The higher the degree of 
weathering, the more clayey is the resulting soils. The textural names of soils are as 
listed below, while the textural classes are as shown in Figure 3.2. 
• Clay 
• Clayey loam 
• Sand 
• Sandy clay 
• Sandy clay loam 
• Sandy loam 
• Loam 
• Loamy sand 
• Silt 
• Silty clay 
• Silty loam 
• Silty clay loam 
73 
100% Clay 
•6- 90 80 70 60 50 40 30 20 10 ^ 
% Sand 
Figure 3.2 Soil textural classes guide 
Soil Structure 
Soil structure refers to soil particle aggregates based on the aggregate that can be easily 
broken under very slight pressure. For example, sandy soil is very friable in nature, and 
connot be formed into any structure, thus it is said to be structureless. Unlike clay soil 
which cannot be easily broken up. Clay soil is considered to be of very poor structure, 
as it is too blocky. Structure influences the supply of water, air and nutrients for plant 
growth. Ideally, there should be an assortment of fine and coarse aggregates arranged 
in a pattern that will allow adequate water storage and aeration. The aggregates must 
be stable enough so that the structure can be preserved for a long time. Figure 3.3 
displays some common soil structures in Peninsular Malaysia soils. 
74 
Sub-angular blocky Angular blocky Granular Platy 
Prismatic Columnar 
Figure 3.3 Various types of soil pebbler 
Soil Series 
It is important to classify soils in order to efficiently exploit them. Classification of soils 
also helps to determine their suitability and the type or amount of agro-management 
input to be given. In rubber cultivation, soil management is important to maximise yield 
of a clone in a particular area, and this depends partly on the soil series. A soil series 
can be defined as a group of soils, similar in profile properties, formed from parent 
material of the same geological origin. Table 3.2 describes a number of soil series 
found in rubber-growing areas of Peninsular Malaysia. 
75 
TABLE 3.2 SOME SOIL SERIES IN RUBBER-GROWING AREAS OF PENINSULAR MALAYSIA 
Series Parent material Colour Texture Structure Consistency 
Batu Anam Shale Pale yellow to light grey Clay to silty clay 
Strong, medium to coarse angular 
blocky to prismatic Firm and very firm 
Durian Shale Strong brown to yellowish red Silty clay to clay 
Moderate, medium angular blocky to 
prismatic Firm and very firm 
Gajah Mati Shale Strong brown Clay loam Moderate, medium and fine 
sub-angular blocky Very friable 
Jeram Shale Strong brown to yellowish red Sandy clay loam to clay 
Strong coarse granular and fine 
sub-angular blocky Friable to firm 
Kuala 
Brang Shale 
Dark greyish brown 
to light olive grey 
Fine sandy loam to clay 
loam 
Strong medium granular to weak very 
coarse sub-angular blocky Friable to firm 
Melaka Shale Brownish yellow or 
redder 
Clay loam to fine sandy 
clay 
Strong, fine and medium sub-angular 
blocky Very friable 
Munchong Shale Yellowish brown to 
strong brown 
Silty clay loam to silty 
clay 
Moderate to strong fine and medium 
sub-angular blocky 
Friable to firm with 
depth 
Pohoi Shale Pale brown to 
variegated yellow Clay loam to clay 
Moderate, medium and coarse 
crumbs and granular to strong, coarse 
prismatic 
Friable to very 
firm 
Prang Shale Yellowish red Heavy clay Moderate to strong, fine and medium 
sub-angular blocky Very friable 
Rengam Granite Brownish yellow to yellowish brown 
Coarse sandy clay loam 
to coarse sandy clay 
Weak to moderate, medium 
sub-angular blocky Friable 
Jerangau Granodiorite Strong brown to yellowish red 
Fine sandy clay loam to 
fine sandy clay 
Moderate to strong, fine and medium 
sub-angular blocky 
Friable to firm with 
depth 
Kuantan Basalt Strong brown to yellowish red Clay to heavy clay 
Moderate to strongly developed, 
medium granular and sub-angular 
blocky 
Very friable 
Segamat Andesite Yellowish red to red Clay to heavy clay Strongly developed medium 
sub-angular blocky Very friable 
TABLE 3.2 SOME SOIL SERIES IN RUBBER-GROWING AREAS OF PENINSULAR MALAYSIA (contd.) 
Series Parent material Colour Texture Structure Consistency 
Kulai Rhyolites and 
volcanic tuffs 
Pale yellow brown to 
strong brown Loam to silty clay Weak, angular blocky Firm 
Yong Peng Dacite Strong brown to yellowish 
red Clay loam to clay 
Moderate, medium sub-angular 
blocky to strong angular blocky Friable 
Seremban Schist Reddish yellow to yellowish red 
Fine sandy clay loam to 
fine sandy clay 
Fine sandy clay loam to fine 
sand clay Friable to firm 
Batang 
Merbau 
Schist and 
quartzite Yellowish brown 
Fine sandy loam to 
sandy clay loam 
Moderate, medium sub-angular 
blocky Friable to firm 
Bungor Quartzite or 
shale 
Yellowish brown of 
brownish 
Fine sandy clay loam to 
fine sandy clay 
Strong, medium sub-angular 
blocky Friable to firm 
Serdang Sandstone Strong brown to yellowish yellow 
Coarse sandy loam to 
sandy clay loam 
Weak to moderate, fine and 
medium sub-angular blocky Friable 
Kedah Quartzite and 
sandstone Strong brown 
Sandy loam to sandy 
clay 
Weak to moderate, medium and 
fine sub-angular blocky Friable to firm 
Harimau Older alluvium Yellowish brown to brownish yellow 
Sandy clay loam to 
sandy clay 
Weak to moderate, medium 
sub-angular blocky Friable to firm 
Ulu Tiram Older alluvium Yellowish brown Sandy clay loam to gravelly loam 
Weak, medium crumbs to weak 
medium sub-angular blocky Friable to firm 
Tampoi Older alluvium Reddish yellow to yellowish red 
Sandy loam to sandy 
clay loam 
Weak crumbs to coarse 
sub-angular blocky Friable to firm 
Klau Sub-recent 
alluvium 
Yellowish brown to 
brownish yellow 
Sandy clay loam to 
sandy clay 
Weak to moderate, medium 
coarse sub-angular blocky Friable to firm 
Holyrood Sub-recent 
alluvium Yellowish brown 
Sandy loam to sandy 
clay loam Weak, fine sub-angular blocky Very friable 
TABLE 3.2 SOME SOIL SERIES IN RUBBER-GROWING AREAS OF PENINSULAR MALAYSIA (contd.) 
Series Parent material Colour Texture Structure Consistency 
Sogomana Sub-recent alluvium Light grey to white Silty clay to clay Weak, coarse prismatic breaking to angular blocky Firm 
Sitiawan Sub-recent alluvium Pale yellow to yellow Clay Moderate, coarse angular blocky Firm 
Lunas Sub-recent alluvium Dark greyish brown to light grey Coarse sand clay loam 
Weak, fine crumbs to 
moderate weak, very coarse 
angular and sub-angular 
blocky 
Very friable to 
firm 
Sungai 
Buloh 
Recent riverine 
alluvium 
Dark brown to yellowish 
brown and yellow Coarse sand 
Structureless to weak, fine 
crumbs 
Loose to very 
friable 
Briah Marine alluvium Light brown to brownish grey Silty clay loam or silty clay 
Strong or moderate 
sub-angular blocky 
Friable for with 
depth 
Selangor Marine alluvium Dark greyish brown or greyish brown Silty clay 
Weak to moderate, coarse 
prismatic or angular blocky 
Friable to firm 
with depth 
Linau Marine alluvium Dark brown 
Organic clay to muck 
with some decayed plant 
remains 
Weakly structured Friable to firm 
with depth 
Senai Gabbro Brown to yellowish red Clay Moderate, fine and medium to moderate sub-angular Friable to firm 
Subang 
Organic enriched 
alluvial deposit over 
compact sand 
Dark brown to very pale 
brown 
Organic sandy loam to 
sand 
Strong, medium granular 
and sub-angular blocky to 
structureless 
Friable 
Organic clay 
and mucks 
Organic deposits 
accumulation Not fully investigated yet 
Peat Organic deposits 
accumulation Not fully investigated yet 
Soil Limitation 
While some classes of soils have properties desirable for growth of rubber, the poor 
classes have properties which limit optimum growth and performance. The common 
limitations are as described below 
Very serious limitations: 
• Slopes steeper than 16 degrees 
• Massive thick hard-pan within 23 cm of the surface 
• More than 75% rock outcrops in a unit area 
• Permanent water table within 23 cm of the surface 
• Acid peat layer thicker than 23 cm 
• More than 90% sand 
• Very low nutrient level 
Serious limitations: 
• Slopes steeper than 9 degrees but below 16 degrees 
• Massive thick hard-pan between 20-50 cm of surface 
• Between 50 to 75% rock outcrops in a unit area 
• Permanent water table between 20-50 cm of the surface 
• Very compact soil 
• Very sandy or clayey 
• Susceptible to moisture stress 
• Low nutrient level. 
Less serious or minor limitations: 
• Weak structure within 90 cm of surface 
• Moderate drainage conditions 
• Massive thick hard-pan below 50 cm from surface or loosely packed gravels within 
50 cm from surface 
• Less than 50% rock outcrops in a unit area 
• Susceptible to flooding 
• Susceptible to erosion 
• Below optimum nutrient level. 
79 
Soil Limitation Classification 
Based on the above information, the following soil limitation classifications are 
recommended for rubber cultivation: 
• Class I - Having no limitation to rubber cultivation 
• Class II - Having one or more limitations to rubber cultivation 
• Class III - Having at least one serious limitation 
• Class IV - Having more than one serious limitation for rubber cultivation 
• Class V - Having at least one very serious limitation for rubber cultivation 
Land suitability is also categorised into orders. Two orders are recognised - suitable (S) 
and unsuitable (N) for rubber cultivation. The sub-division are as follows: 
• S1 - Highly suitable for rubber cultivation 
• S2 - Moderately suitable for rubber cultivation 
• S3 - Marginally suitable for rubber cultivation 
• N1 - Currently unsuitable for rubber cultivation 
• N2 - Permanently unsuitable for rubber cultivation 
Soil Productivity Classification 
Studies have shown that yield of rubber is dependent on soil properties. Munchong, 
Rengam and Jerangau series have good physical properties and therefore the yields 
are higher. Selangor and Briah series have very poor physical properties, and hence 
poor yield. The physical properties of Holyrood and Tampoi are said to be intermediate, 
thus, the yields are also intermediate. Based on the above information, soils are divided 
into five productivity classes (Table 3.3). 
TABLE 3.3 SOIL PRODUCTIVITY CLASSES 
Class Yield category (kg/ha/year) Soil series 
IA > 1,350 Munchong, Prang, Kuantan, Segamat 
IB 1,250-1,350 Rengam, Jerangau, Yong Peng, Bungor 
II 1,150-1,250 Senai, Harimau, Batang Merbau, Subang, Klau, Serdang 
III 1,050-1,150 Ulu Tiram, Pohoi, Holyrood, Lunas, Kuala Berang, Tampoi 
IV 1,000-1,050 Batu Anam, Durian, Seremban, Melaka, Gajah Mati, Kedah, Marang 
V < 1,000 Briah, Selangor, Sungai Buloh, Linau, Peat 
80 
Desirable Soil Properties for Rubber Cultivation 
Soils have different physical, chemical and physiographical combinations. Their 
suitabilities for rubber cultivation also vary. The desirable properties for rubber cultivation 
are listed below: 
• Soil depth of up to 100 cm 
• Well drained 
• Good soil aeration 
• Good structure 
• Able to retain water and nutrients 
• Good texture - 35% clay and 30% sand 
• No peat or peat layer not thicker than 23 cm 
• Slopes not exceeding 16 degrees 
• Water table deeper than 100 cm from surface 
• At least medium status of NPKMg 
• Not deficient in minor nutrients 
• Level of pH around 4.5 
• Not saline or no acid sulphate 
Agro-management Practices to Overcome Soil Limitations 
Different specific agro-management practices and inputs are required on different soils 
as a result of their limitations. These are summarised below: 
• Establishment of pure creeping legume cover crops for all situations 
• Terracing for slopes exceeding 16% 
• Silt-pittings or bundings for slopes below 16% 
• Contour ploughing only for slopes below 16% 
• Contour planting on slopes of 2-8% 
• Efficient drainage system for high water table clay soils 
• If mechanical ploughing is intended for heavy clay textured soils, it must be 
carried out at the correct soil moisture content 
• Avoid heavy crown clones for high water table areas, sandy and lateritic 
soils 
• Carry out extra and split application of fertilisers for the sandy textured and 
peaty soils 
81 
SOIL CONSERVATION 
Soil conservation can be considered as maintaining, protecting, and improving the soil 
for agricultural purposes. Crop productivity depends very much on the top soil, where 
plant nutrients are concentrated. As this rich layer is at the top of the soil surface, plant 
nutrients can easily be lost, removed or damaged by various natural processes. 
Objectives of Soil Conservation 
The objectives of soil conservation are therefore to: 
• reduce soil erosion 
• maintain and improve soil structure 
• maintain organic material content in the soil 
• utilise efficiently available water 
• maintain soil fertility by reducing nutrient loss, and to replace those that 
are lost 
Soil Erosion and Its Consequences 
Soil erosion is a natural process in which loss of rich top soil occurs by the action of 
rain, wind and sunlight. In the tropics, due to abundant rainfall, much of the erosion is 
caused by water. The degree of erosion then depends greatly on the amount of rainfall 
and the steepness of the terrain. 
When erosion occurs, the nutrient-rich top soil is washed away. This can affect 
plant growth and later, its yield. In areas where the terrain is too steep, more serious 
consequences can take place, such as exposure of tree crop roots followed by falling 
trees. 
Types of Erosion 
There are two main types of erosion, the geological and the accelerated erosion. 
Geological erosion is the erosion of land in its natural environment, without man's 
influence. It occurs naturally by the action of rain, wind, temperature variations, gravity 
and vegetation. In fact the present land relief of Malaysia is the result of geological 
erosion. It is an on-going process, and there is nothing much that we can do about it. 
82 
Accelerated erosion is mainly caused by man in his effort to bring about 
development by land clearing. Still, the chief agent of accelerated erosion is water. The 
various types of water erosion are discussed below: 
Sheet erosion. Sheet erosion is the uniform removal of a thin layer or sheet 
of top soil, by falling rain, followed by surface run-off removal. Usually it takes place 
unnoticed. It occurs on smooth surface and on uniform or regular slopes. 
Rill erosion. In their natural form, most soil surfaces are irregular with low and 
high places, such as runnels, furrows and mounds. When rain falls, water flows into 
depressions causing rill formation. The eroded soil surface can become deeper with 
time, leading to the formation of gully erosion (Figure 3.4 a). 
Gully erosion. Gully erosion is a more serious form of rill erosion. The soil 
surface becomes so deformed, with large ugly-looking scars, which sometimes make 
agricultural development almost impossible (Figure 3.4 b). 
Landslide. Landslide can be considered as a more serious form of gully 
erosion. Besides destroying the soil fertility, it causes damage to crops, properties, 
waterways, highways and probably lives, too. It normally occurs on very steep slopes 
of hills undergoing development and road cuttings. It causes the detachment of huge 
blocks of soil from the main hill during heavy and prolonged rainfall (Figure 3.4 c). 
Minimising Soil Erosion 
Soil erosion can be minimised by reducing the speed of running water and at the same 
time encouraging it to penetrate the soil, thus reducing surface run-off. Protecting the 
soil surface from direct rainfall, wind and sunlight also helps to reduce erosion. Steps 
to be considered to minimise the dangers of erosion are: 
• Contour terracing for slopes exceeding 11 degrees 
• Contour bunding for slopes below 11 degrees 
• Contour platforming for slopes below 11 degrees 
• Contour silt-pitting for slopes below 11 degrees 
• Contour ploughing where required 
• Contour planting where necessary 
• Mulching around crops 
• Cover cropping for all land situations (Figure 3.5 and Table 3.4) 
83 
a) Rill erosion 
b) Gully erosion 
c) Landslide erosion 
Figure 3.4 Various types of soil erosion 
84 
(a) Contour terracing 
(b) Contour bunding 
Figure 3.5 Contour terracing and bunding 
TABLE 3.4 EFFECT OF COVER CROPS ON REDUCTION OF SOIL EROSION 
Type of soil Quantity of 
rain (cm) 
Quantity of soil eroded (tonne/ha) 
Exposed* Grassed Nephrolepls" 
Rengam 4 - 5 292 103 44 Negligible 
Serdang 3°- 5° 325 132 177 59 
* Bare land surface or no vegetation at all 
** A type of fern 
85 
Soil Tillage 
Although no tilling is required for rubber cultivation, ploughing and harrowing can be 
carried out, if short term crops are to be inter-grown. The main aim of tilling is to reduce 
the compactness of the soil to facilitate root development at the initial stage of plant 
growth. But the soil can become compact, if ploughing is not properly carried out. If the 
soil is ploughed after a heavy downpour, it becomes more compact and hard. The soil 
must be allowed to dry sufficiently. As a guide, sandy soils such as the Sungai Buloh, 
Holyrood and Serdang series, can be ploughed two to three days after rainfall, while 
the medium soils (Rengam and Munchong series), four to five days and the clayey soils 
(Sitiawan dan Sogomana series), one week. 
Manuring 
Soil fertility has become the main factor in soil management. By maintaining high soil 
fertility, several conditions which assist in reducing erosion can be achieved. Good 
plant growth rate which covers the soil surface, also reduces rainsplash, surface run-off 
and at the same time preserve water in the soil for plant/crop usage. To achieve a high 
level of fertility, correct fertiliser must be adequately applied. This can be determined by 
soil and foliar analysis, fertiliser trials and crop growth survey. Such efforts can lead to 
a more specific fertiliser application known as discriminatory fertiliser usage. 
In crop cultivation, soil fertility is of utmost importance because; it determines the viability 
of the crop. Below are several factors concerning soil management that are considered 
important. 
• Knowing the most suitable time to carry out land development for rubber 
cultivation - planning, clearing, tilling, planting and others 
• Reducing soil erosion to the maximum 
• Utilising available organic fertiliser to the maximum 
• Increasing nutrient status of the soil by the use of chemical fertilisers 
• Mulching around crop where possible and suitable 
• Maintaining pure legume covers to the very end of their life cycles 
86 
TERRACING 
Terracing is the cutting of steps or paths horizontally on hill slopes following their 
contours. Terraces function as planting rows on hill slopes, since planting of rubber is 
done on and along them. 
Objectives of Terracing 
The objectives of constructing terraces on hill slopes are to: 
• reduce soil erosion 
• retain and preserve water in the soil 
• facilitate holing and planting operations 
• facilitate manuring 
• facilitate general field maintenance 
• facilitate movements on hill slopes 
Method of Terracing 
Terraces are constructed along contour lines marked out during field lining. This is to 
ensure that they are level. A cut is made into the hill slope, about 60 cm above or below 
the contour line, and the earth is pulled backward (downhill) to create a path of 1-1.5 m 
wide. This cut is continued to the end of the contour line. The spoil is heaped along the 
lower edge of the slope and given a beating to form a strong bund. The terrace should 
slope inward into the hill with a back drop of 25-30 cm from the horizontal or declining 
10-20°, depending on the slope gradient (Figure 3.6). At intervals of 8 m along the 
terraces, earth-stops are made to check lateral flow of water, by leaving 30 cm width of 
uncut earth. Thirty metres of terrace length can be completed per man-day. For a large 
area mechanical terracing is more appropriate. A light bulldozer such as the D4 model 
fitted with a tilting blade that can cut 2-4 m width of terrace at the rate 100 m per hour is 
normally used. Earth-stop at 20 m intervals are sufficient for such terraces. 
Figure 3.6 Cross-section of terrace 
87 
The total length of terraces in a hectare of hilly area can be calculated, if the average 
distance between terraces is known, by the following formula: 
Total Length of Terrace = Area per hectare (m2) 
Average distance between terraces (m) 
Fixing Planting Points 
In view of the irregularity of the distances between terraces, it is advisable to make 
adjustments to the planting points (from the original distance of 2.5 m) where necessary 
for a more uniform planting density per hectare. This can be achieved by marking off 
all the terraces at 20 m intervals. At the beginning and end of every 20 m along the 
terraces, the horizontal distance between adjoining terraces is measured orthogonally 
(Figure 3.7). The measurements are then summed up, and in reference to Table 3.5, 
the planting distance along the 20 m mark is obtained, based on the planting density of 
500 plants per hectare. 
First terrace 
Second terrace^. a 20 m 
2 _ , 
- = t -
Third terrace—^ b i : 
£ _- : 
1° 
Figure 3.7 Layout for planting point adjustment along terrace 
TABLE 3.5 PLANTING POINTS FOR 500 PLANTS PER HECTARE ON TERRACE 
Sum of a,b,c,d 
(m) 
Average horizontal 
distances between 
terraces (m) 
Number of plants 
per 20 m terrace 
length 
Distance between 
planting points 
(m) 
24.3-27.2 6.1-6.8 5 4.00 
27.3-32.1 6.9-8.0 6 3.33 
32.2-37.0 8.1-9.2 7 2.86 
37.1-41.9 9.3-10.5 8 2.50 
42.0-46.7 10.6-11.7 9 2.22 
46.8-48.9 11.8-12.3 10 2.0 
88 
GROUND COVER CROPS 
In agricultural practices, exposed soil surface is most undesirable, as it can cause much 
damage to the top soil, rendering it no longer suitable for growing crops. The main 
planted crop, such as rubber, is insufficient to provide full coverage to the soil surface, 
especially during the first few years of establishment. Plants which are more densely 
populated are needed to perform such function. They are known as ground cover 
plants or ground covers. Ground covers can be defined as small plants, either planted 
or self-grown such a s weeds, catch crops and leguminous plants. 
Weeds 
Weeds can be defined as plants which are self-grown. Desirable weeds are those that 
utilise very little nutrients from the soil, but grow vigorously and return lots of green litter 
to the soil. Undesirable weeds are those that take up lots of nutrient but return very little 
litter to the soil. Most grasses, bracken, sedges and others come under this category 
of weeds. Among them, Imperata cylindrica and Mikania micrantha are regarded as 
very harmful to rubber growth. Their roots are believed to release toxic substance that 
inhibits growth of rubber. Only the desirable weeds should therefore be allowed to grow 
in the rubber plantation, while the undesirables are eradicated. 
Catch Crops 
Catch crops are short term crops, usually grown between rubber planting rows. They 
are mostly food crops, such as maize, groundnuts, soya bean, vegetables and others. 
They are able to provide temporary income to the farmers and at the same time function 
as cover crops. Such practice is only suitable during the first two or three years of 
rubber cultivation, because of the shading effect from rubber trees. 
Leguminous Plants 
Leguminous plants (Leguminoseae sp.) are those that can fix atmospheric nitrogen and 
convert it to nitrates, through the bacteria present in the root nodules of such plants. 
From the soil fertility point of view, this type of ground cover is most preferred. Legume 
covers are divided into two groups namely creepers and non-creepers. Non-creepers 
are further divided into bushy and prostrates (Table 3.6). 
89 
TABLE 3.6 SOME COMMON LEGUME COVER PLANT SPECIES 
Creepers 
Non-creepers 
Bushy Prostrates 
Calopogonium mucunoides Moghania macrophylla Stylosanthes gracilis 
Calopogonium caeruleum Tephrosia Candida Desmodium ovalifolium 
Centrosema pubescens Acasua villosa Desmodium groides 
Pueraria phaseoloides Crotalaria anagroides Classia obtusifolia 
Mucuna cochinchinensis Crotalaria striata Mimosa invisa 
Phaseolus pubescens Leucaena glauca 
Clitoria rubigonosa 
Among the legume covers, the creepers are preferred, as they cover the soil 
surface very fast. Their detailed descriptions are given in the later part of this Chapter. 
Advantages of creeping legume covers. Numerous advantages can be obtained 
by establishing creeping leguminous covers in the rubber plantations, and they are 
listed below: 
• Protect the soil surface, thus reducing soil erosion and direct sunlight 
(Table 3.7) 
• Assist in the preservation of water in the soil 
• Reduce soil temperature, thus delaying the decomposition of organic matter 
• Help to loosen the soil and facilitate aeration and drainage in the soil 
• Improve soil structure and other related physical properties 
• Add organic matter to the soil in the form of leaf litter 
• Fix atmospheric nitrogen and convert it to nitrate for plant usage 
• Encourage feeder root development near the soil surface, hence more 
efficient uptake of nutrients (Table 3.8) 
• Provide good nitrogen nutrition to rubber during the first two to five years 
of growth (Table 3.9) 
• Reduce cost in nitrogenous fertiliser 
• Reduce leaching losses of nutrients deep into the soil 
• Enhance growth of rubber, resulting in early maturity (Tables 3.10-3.11) 
• Increase crop yield (Table 3.12) 
• Improve bark renewal 
• Help to suppress weeds growth and thus reduce cost of weed control 
• Reduce overall field maintenance of rubber plantation 
• Assist in faster decomposition of old tree stumps, thus reducing root 
disease incidence in young plantings 
90 
TABLE 3.7 EFFECT OF COVER CROPS ON SOIL EROSION 
Type of cover Thickness of soil accumulated on terrace (cm) 
Pueraria phaseoloides 11.0 
Grasses 12.5 
Tephrosia Candida 14.0 
Crotalaria anagroides 15.5 
Exposed * 19.0 
*No covers at all 
TABLE 3.8 EFFECT OF COVERS ON FEEDER ROOT DEVELOPMENT OF RUBBER 
Type of cover Weight of feeder roots (mg/1000 cc soil) 
Legume 623 
Grasses 330 
Mikania 251 
TABLE 3.9 NUTRIENTS RETURNED TO THE SOIL IN FIVE YEARS 
BY TWO TYPES OF COVERS (KG/HA) 
Type of cover N P K Mg 
Legume 226-535 18-27 85-131 15-27 
Grasses 24-65 31-16 31-86 5-9 
TABLE 3.10 EFFECT OF COVERS ON GROWTH OF RUBBER FIVE YEARS 
AFTER PLANTING (CM) 
Type of cover Inland soil Coastal clay soil 
Legume 40 41 
Grasses 36 40 
Imperata cylindrica 18 24 
91 
TABLE 3.11 EFFECT OF COVERS ON THE IMMATURITY PERIOD OF RUBBER 
Type of cover Seremban series soil (months after planting) 
Melaka series soil 
(months after budding) 
Legume 61 56 
Grasses 68 59 
TABLE 3.12 EFFECT OF COVERS ON THE ACCUMULATED YIELD OF RUBBER (KG/HA) 
Type of cover 148 months 159 months 
Legume 10,145 11,843 
Grasses 8,220 10,449 
Disadvantages of legume creeping covers. Legume creeping covers also pose 
some drawbacks in rubber plantation. As living plants, they too compete with rubber 
for nutrient and water from the soil, space, sunlight and air. They provide sanctuary for 
certain rubber pests such as molluscs and insects. In view of their creeping nature, they 
climb up the rubber plants, choking and bending them. But the abundant advantages 
they give to rubber offset these disadvantages. 
Legume cover species. There are several species of creeping legumes, but 
only five are commonly planted in rubber plantations. Calopogonium mucunoides 
has medium size oval-shaped leaves and small-size seeds. It establishes very fast, 
but has a life span of below two years. Centrosema pubescens has small leaves, 
but larger seeds. It is slow to establish, but tolerates shade. Pueraria phaseoloides 
has large broad leaves and smallest seeds. It establishes fast and tolerates shade. 
Calopogonium caeruleum has also medium-size leaves, medium-size and flat seeds 
and is the most shade tolerant of all. Mucuna cochinchinensis has very large broad-
shaped leaves and extra large seeds, it is very vigorous in growth but has a life span of 
below one year . To obtain a good ground cover with all the growth properties present, 
a mixture of the different species is recommended (Table 3.13). 
92 
TABLE 3.13 LEGUME COVER CROP SEED MIXTURES (KG/HA)* 
Legume species Mixture A Mixture B Mixture C 
Calopogonium mucunoides 2.9 4.1 1.8 
Centrosema pubescens 1.2 - -
Pueraria Phaseoloides 1.9 1.2 2.3 
Calopogonium caeruleum - 0.7 0.7 
Mucuna cochinchinensis - - 1.2 
'Based on 80% germination, quantity to be increased accordingly if germination rate is lower 
Method of planting. For planting of legume covers, the land area must first be 
cleared and lined. On hill slopes terraces must be completed. V-shaped drills 2.5 cm 
deep are cut in the soil between rubber planting rows or terraces, the number of drills 
depending on the distance between the planting rows. The distance of the drills nearest 
to the planting rows should be 1.2 m and the distance between drills should be 1 -3 metres. 
For example, three drills are suggested between 5 m inter-rows, and four drills between 
terraces of 8 metres (Figure 3.8). On a hill slope, the top-most drill is laid along the terrace 
lip to provide protection along the filled portion of the terrace . Rock phosphate at 125 kg 
per hectare is applied in the drills. 
• • »^ • • Rubber 
1.2m 
—-— Legume cover 
i.3m, 
5 m Legume cover 
1.3 nt 
; Legume cover 
1.2m | 
i- • • • • • Rubber 
93 
Figure 3.9 Planting out legume cover crop seeds 
94 
The seeds are mixed in a suitable container. They are then soaked in hot water 
at 75 °C (one part of cold water in two parts of boiling water) for two hours. After removing 
excess water, the seeds are innoculated with Rhizobium compost at 10 kg per 50 g packet 
of the compost. The treated seeds are then mixed with equal weight of rock phosphate. 
The seeds are sown in the drills and lightly covered with soil. Immediately after planting, 
pre-emergent herbicide, such as Lasso at 3 litres in 450 litres of water per hectare is 
blanket-sprayed (Figure 3.9). 
Maintenance of legume covers. After three to four weeks, work on legume 
cover purification must begin by manually removing weeds that emerge. Compound 
fertiliser containing NPKMg at 15:15:6:4% is applied on the covers at 63 kg per hectare 
(Figure 3.10). When the legumes have provided 10-20% coverage, the weeds are 
controlled by herbicides, such as 2.5 litres Paraquat + 1.2 litres Velpar K-51 in 450 litres 
of water per hectare. 
Pests of legume covers such as slugs and snails are controlled by poisoned 
bait, while the insect pests are controlled by spraying insecticides such as 48 g Dipterex 
SP or Sevin 85S in 20 litres of water. 
Rock phosphate is again dusted over the legume cover crops at 250 kg/ha/ 
year, when they are one, three and eight months old, and thereafter, annually. Legume 
cover crops are expected to be fully established in less than a year (Figure 3.10). 
(a) Applying NPKMg compound fertilisers (b) Dusting rock phosphate 
Figure 3.10 Manuring legume cover crops 
95 
Through breeding and selection, MRB succeded in developing a selection of latex-timber 
clones that excellent in rubber production as well as rubberwood production 
96 
CHAPTER 4 
PLANTATION DEVELOPMENT 
Rubber plantation development is a huge undertaking as its operations involve labour 
force and agricultural machinery. The complexity depends on the size of the land 
area to be developed as completion of each field operation must coincide with the 
season. In Malaysia, rubber planting can be divided into two types i.e. new planting 
and replanting. 
New planting is defined as planting of rubber in an area where rubber was 
never planted before. Usually, this area is jungle land which is suitable for agriculture 
and where useful timber had been extracted. The land could also have been planted 
with other crops and is now undergoing agricultural diversification. Individual new 
plantings for smallholders are almost non-existent today, except in isolated cases of 
pocket land alienation. Most of the new plantings are carried out in large scale by the 
government development agencies. Financial resources for such development come 
from Government grants, commercial financial institutions, the World Bank and the 
Asian Development Bank. 
Replanting is defined as planting of rubber in an area already planted with the 
same crop with the aim of replacing the old uneconomic trees with high quality planting 
materials. In 1951, the Government initiated a replanting scheme to rehabilitate 
uneconomic rubber areas. The scheme is financed by a special cess collected from 
rubber exported; currently at 9.92 sen per kilogramme, plus a special Government 
grant. The implementing agency for this project is RISDA. Smallholdings are normally 
replanted individually, but now RISDA prefers them to be grouped in block basis with 
good and efficient management back-up to ensure greater rate of success. 
WORK OPERATIONS 
Plantation development work operations are numerous, from the major to the minor 
ones. As there are two types of rubber planting, their field operations also differ, 
especially in the land clearing work. 
97 
New planting. For new planting, the following work operations are normally 
required to be carried out: 
• Constructing drainage (if necessary) 
• Underbrushing of ground vegetation 
• Felling of jungle trees by chainsaw cutting or by bulldozing 
• Drying of felled timber 
• Burning - primary burning 
• Pruning and stacking 
• Burning - secondary burning 
• Constructing agricultural road (if necessary) 
• Tilling (if necessary) 
• Field lining - straight or contour 
• Terracing (if necessary) 
• Establishing legume cover crops 
• Holing 
• Perimeter fencing (if necessary) 
• Transplanting of polybag rubber planting materials 
Replanting. For replanting, the following work operations are normally 
required: 
• Underbrushing or blanket chemical spraying of ground vegetation 
• Felling of old rubber stand by chainsaw cutting and poisoning of stumps 
Or 
• Poisoning old rubber stand to facilitate rotting 
Or 
• Felling (uprooting) of old rubber stand by bulldozing or mechanical winching 
• Removing felled rubberwood 
Or 
• Drying of felled rubberwood 
• Burning - primary burning 
• Pruning and stacking 
• Burning - secondary burning 
• Constructing drainage (if necessary) or servicing existing drainage system 
• Constructing agricultural roads (if required) or servicing existing ones 
• Tilling (if necessary) 
98 
• Field lining - straight or contour 
• Terracing (if necessary) or servicing existing ones 
• Establishing legume cover crops 
• Holing 
• Perimeter fencing (if necessary) 
• Transplanting of polybag planting materials 
Work Schedule 
In plantation development, it is most important to draw up a work programme, showing 
the works to be carried out and the times for their completion (Tables 4.1 and 4.2). This 
is because all land preparations must be completed before the main rainfall season 
begins, when it is most suitable to carry out transplanting of rubber. The main rainfall 
season in Peninsular Malaysia is usually from October to December. This may differ 
from state to state by a month either earlier or later. 
Development Cost 
The development costs for new planting and replanting are almost the same. Perhaps, 
the initial land clearing for the new planting may be higher as it involves the clearing of 
thick vegetation, whereas in a replanting, only some 300 old rubber trees per hectare 
have to be dealt with. Moreover, a replanting can obtain additional income from the 
sale of rubber timber, which is in great demand these days, thus reducing further its 
development cost. Other aspects of field operations that can increase the development 
cost are terracing and drainage. Plantation development cost, from land clearing to 
crop maturity, are detailed in Tables 4.3 and 4.4. 
Land Clearing 
All living plants need enough nutrients, water, air, sunlight and space in order to 
survive and grow vigorously. These also apply to crops such as rubber. Other forms 
of vegetation around them pose as competitors. The lesser the competitors, the better 
will be the growth of the planted crops. Therefore, for plantation development, jungle 
and old rubber areas must be cleared of all vegetations, before planting is carried out. 
Some of the existing vegetations, especially old rubber trees, may have been hosts to 
root disease fungus. Therefore, removing them first may help eliminate or reduce root 
disease in young plantings later on. Again, cleared and cleaned areas facilitate land 
preparation work such as lining, terracing, holing and planting. 
99 
TABLE 4.1 SAMPLE WORK SCEHEDULE FOR 2,000 HA NEW PLANTING 
Work operation Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov 
Demarcating block 
Underbrushing, felling and 
drying 
Burning - Primary 
Pruning, stacking and reburning 
Constructing drainage 
Constructing roads and terracing 
Holing and fencing 
Establishing legume covers 
Transplanting rubber 
TABLE 4.2 SAMPLE WORK SCHEDULE FOR 50 HA REPLANTING* 
Work operation Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 
Bulldozing and removing timber 
Burning of left-over debris 
Servicing of old road 
Lining and terracing 
Holing 
Establishing legume cover crops 
Transplanting polybag materials 
*A hilly area at RRIES, Sungai Buloh (1990) that needs 10% terracing 
TABLE 4.3 RUBBER NEW PLANTING COST (RM/HA)* 
Work Operation Year Total % 0 1 2 3 4 5 6 
Land Clearing 720.00 180.00 900.00 6.0 
Terracing@500m/ha 600.00 125.00 725.00 4.9 
Lining and holing 510.00 510.00 3.4 
Planting and maintenance of legume covers 600.00 100.00 700.00 4.7 
Planting materials 1,215.00 1,215.00 8.1 
Planting labour (inclusive transport) 540.00 540.00 3.6 
Replacement 121.50 36.50 36.50 194.50 1.3 
Weeding 416.00 333.00 187.00 187.00 104.00 104.00 1,331.00 8.9 
Manuring 606.00 819.00 716.00 1,050.00 1,040.00 1,040.00 5,271.00 35.3 
Disease and pest control 60.00 40.00 80.00 70.00 20.00 20.00 290.00 1.9 
Pruning/census/thinning 335.00 70.00 70.00 35.00 510.00 3.4 
Roads and bridges 450.00 350.00 100.00 70.00 50.00 100.00 120.00 1,240.00 8.3 
Drainage@10m/ha 30.00 30.00 5.00 40.00 10.00 115.00 0.8 
Proportion of general charges (supervision/sundry 
expenses/other costs) 200.00 200.00 200.00 200.00 200.00 200.00 200.00 1,400.00 9.4 
Total 4,986.50 2,103.50 1,868.50 1,363.00 1,637.00 1,499.00 1,484.00 14,941.50 100.0 
Note : 
1.450 trees/ha 
2. Chemical and Fertilizer price as at January 2009 
3. Terracing@40% of total area. 
Table 4.4 RUBBER REPLANTING COST (RM/HA)* 
Work Operation 
Year 
Total % 
0 1 2 3 4 5 
Land Clearing 600.00 600.00 5.1 
Reterracing 180.00 100.00 280.00 2.4 
Lining and holing 480.00 480.00 4.1 
Planting and maintenance of legume covers 600.00 100.00 700.00 5.9 
Planting materials 1,215.00 1,215.00 10.3 
Planting labour (transport included) 540.00 540.00 4.6 
Replacement 121.50 36.45 36.45 194.40 1.6 
Manuring 606.00 819.00 716.00 1,050.00 1,040.00 4,231.00 35.8 
Weed control 416.00 333.00 187.00 187.00 104.00 1,227.00 10.4 
Disease and pest control 60.00 40.00 80.00 70.00 20.00 270.00 2.3 
Pruning/census/thinning 45.00 45.00 60.00 10.00 10.00 170.00 1.4 
Roads and bridges maintenance 240.00 60.00 60.00 50.00 50.00 120.00 580.00 4.9 
Drainage maintenance 30.00 30.00 5.00 40.00 10.00 115.00 1.0 
Proportion of general charges (sundry expenditure/ 
supervision/ other costs) 200.00 200.00 200.00 200.00 200.00 200.00 1,200.00 10.2 
Total 4,206.50 1,653.45 1,538.45 1,333.00 1,577.00 1,494.00 11,802.40 100.0 
Note : 
1.450 trees/ha 
2. Chemical and Fertilizer price as at January 2009 
Clearing of Jungle Land 
Jungle clearing (Figure 4.1(a)) is carried out either by manual felling or mechanical 
uprooting. These are described below. 
Manual felling. First of all, the area to be cleared is demarcated. A rentis of 
2 mm width is cut around the boundary. For a very large area, it is advisable to divide it 
into smaller blocks of, say 40-80 hectares. Clearing work is then done block by block to 
facilitate supervision, in which case, each block is clearly demarcated by such rentice as 
mentioned earlier. Underbrushing is done to all ground vegetation. They are spread at 
the same thickness on the ground to help in the burning process later on. Jungle trees 
are then felled by chainsaw. The height of cutting varies from 15 cm to the buttress, 
depending on the size of the trunk. The trees should be felled in one direction to facilitate 
burning. Felling trees across roads, ravines, and swamps must be avoided. Usually 
a group of four to five trees close together is felled, the largest of them chosen as the 
kingpin. Wedge-shaped cuts are made on one side of the rest of the trees in the group 
facing the direction to be felled. Then a complete cut is made to the kingpin, and when 
it falls, it knocks down the rest of the trees in the group. Large branches are pruned off 
to create a compact condition of the felled timber and to facilitate good burning. The 
trunks of felled timber are cut into two or three pieces. It is always advisable to create 
a fire belt of 20-40 m wide around the area. Trees in the fire belt are left standing to act 
as fire breakers. Such belt is felled and burnt when the inner area has been completely 
cleared and burnt. 
Burning can be carried out as soon as the felled timber is dry. This takes about 
two months. However, there should be no rain within three to four days prior to burning. 
Ten fire points are required for every hectare and they should be placed at the edge of 
the area to be burnt so that the direction of burning is from outside towards the inside 
and finally to the centre. Suitable materials for fire starters should be used. Burning 
should preferably start at noon when conditions are dry. Every precaution must be taken 
with regards to safety. Pruning of the smaller unburnt logs, stacking and reburning them 
can be carried out as soon as the burnt area is safe enough to enter (Figure 4.1(b)). 
However, it must be emphasised here that open burning of jungle land for conversion 
to agriculture land requires a licence from the Department of the Environment (DOE) 
under Section 22(1) of the Environmental Quality Act 1974. 
Mechanical clearing. As mentioned earlier, new plantings are mostly done on 
large scales with the aid of machinery to complete the operation on time. Bulldozers 
are used to push down and uproot jungle trees which are then piled in wind-rows at 
intervals of some 10-20 metres. They are later burnt when adequately dry, and the 
103 
same procedure described earlier is applied. When using this method, underbrushing 
of ground vegetation is normally not done, as it will be destroyed along with the felled 
timber. 
(a) Jungle area before clearing 
(b) Cleared jungle land ready for rubber cultivation 
Figure 4.1 Manually-cleared jungle area for rubber cultivation 
Clearing Old Rubber Area 
There are three options for clearing old rubber areas for replanting. These are manual 
felling, mechanical uprooting and poisoning. The details are given below. 
Manual felling. As usual, underbrushing of ground vegetation is done first. The 
old rubber trees are felled by chainsaw in one direction. Felling across roads, streams 
and swamps must be avoided. Large branches are pruned off and the trunks shortened 
into two or three logs. The cut surfaces on the stumps are painted with creosote to 
prevent root disease spore colonisation, while around the stumps, arboricide such as 
Trichlopyr (Garlon 250) at 5% concentration in kerosene or diesel, is applied to hasten 
decay (Figure 4.2). The timber logs are either taken out for commercial use or left to dry 
and burnt. Drying of rubber timber takes only about one month and the same burning 
technique described for jungle clearing is applicable. 
104 
Mechanical felling. Old rubber trees can be uprooted by bulldozer or backhoe 
or even by lorry-mounted winch (Figure 4.2). The large branches are pruned off and the 
trunks are cut into logs. The logs are either taken out for other uses or pushed in wind­
rows to dry and later burnt. A bulldozer is able to uproot approximately 1,200-2,000 
trees a day. 
(b) Uprooting by lorry-mounted winch 
(c) Felled rubber trees stacked in wind-rows 
Figure 4.2 Clearing old rubber area for replanting 
105 
In the case of replanting, open burnings are allowed only on felled tree stumps 
that cannot be used or recycled for any other purposes. However, efforts must be 
made to reduce the quantity of materials to be burnt. The nearest DOE office must first 
be informed of such activities. It must be emphasised here that where possible, the 
concept of zero burning must be practised. 
(a) After the valuable rubberwood has been (b) Gradual rotting and decomposition continued 
recovered, the remaining debris is stacked after transplanting 
and allowed to decompose naturally 
Figure 4.3 Zero burning replanting 
Poisoning. Old rubber trees can be destroyed by poisoning with suitable 
arboricide such as Trichlopyr (Garlon 250). A 5% concentration is prepared by diluting 
Garlon 250 in four parts of kerosene or diesel. The part of the tree that is to be treated 
must be cleaned of rubber scraps and flaking bark. The arboricide is sprayed or brushed 
evenly over the bark on a band of 40-cm width around the base of the tree. The tree will 
be killed in about 18 months. One litre of the diluted chemical is sufficient to treat five 
trees. The trees are left to rot gradually (Figure 4.3). The ground vegetation (weeds) 
should be given a blanket spray of suitable herbicides. The rest of the field work 
operations can start as soon as the ground vegetation withers. This technique offers 
the following advantages. 
• Zero burning is practised 
• Very useful in areas where the rubber timber cannot be taken out for 
downstream usage 
• Root disease incidence can be eliminated or reduced 
• Carrying out land preparation work under shade is more comfortable 
• Soil erosion is very much reduced 
• Soil fertility is maintained or even enhanced from the decayed biomass 
• Growth of rubber can be enhanced and early maturity expected 
• Cost of plantation development can be reduced to a certain extent 
106 
Drainage 
All living plants need water to survive. However, excess water limits aeration in the 
soil and upsets the breathing of roots. This can affect growth, and if this condition 
is prolonged, death of young plants can occur. Drainage can, therefore, be defined 
as draining or removing excess water in the soil. It is transferred to another area or 
lowered deep into the soil, or both. 
Objectives of Drainage 
Drainage is essential in the rubber plantation. Its objectives are to: 
• remove excess water in the soil 
• ensure that the soil water table is not less than 100 cm from surface 
• ensure there is sufficient water in the soil for crop usage 
• enable plants to obtain sufficient soil air 
• maintain healthy growth of crops 
• increase crop yield (Table 4.5) 
• prevent diseases connected with stagnant water condition of soil 
TABLE 4.5 EFFECT OF DRAINAGE ON YIELD OF CLONE PB 86 
ON SELANGOR SERIES SOIL 
Depth of drain 
(cm) Year of planting 
Average cumulative yield from second to seventh 
year (kg/ha) 
50 1957/1958 5,825 
100 1957/1958 7,155 
Construction of Drains 
There are two types of soil that need drainage - soil with high water table such as the 
coastal clay and inland soils, which are not permeable and cause water to stagnate, 
such as Batu Anam series. In order to determine whether a particular area needs 
drainage, a hole is dug in the soil and the water table is measured. A well-drained soil 
has no water up to 100 cm from the surface. Sometimes, it is difficult to determine this 
during dry weather. If the soil is of bluish grey to greenish grey, it shows that it needs 
drainage. Signs of rust or mottling in the soil indicate that the water table has risen 
to that level during rainy season. If such mottling layer is found 20-30 cm of the soil 
surface, the area needs drainage. 
107 
The outlet, through which excess water is drained, must first be determined. This 
can be a river, stream or lake; if there are no outlets, one must be constructed at the 
lowest part of the area. Main drains of 150 cm deep are dug at 100-200 m intervals 
running in the direction of the outlet. This is followed by subsidiary drains 120 cm deep at 
intervals of 50 m running towards the main drains. Intermediate drains 100 cm deep are 
dug between the subsidiary drains, also running towards the main drains (Figure 4.4). To 
obtain a fast flow of water, all drains must have a drop of 30 cm for every 300 m length. 
Drains can be constructed by manual digging or by mechanical back-hoe. Table 4.6 
gives the specifications of various types of drains mentioned above. 
Outlet Outlet 
Figure 4.4 Plan of plantation drainage 
TABLE 4.6 PLANTATION DRAIN SPECIFICATIONS 
Type of drain Top width (cm) 
Bottom width 
(cm) 
Depth 
(cm) Length per man-day (m) 
Main 150 100 150 5 
Subsidiary 120 80 120 7 
Intermediate 100 60 60 10 
Maintenance of Drains 
Plantation drains must always be functional. This can be achieved by regular maintenance. 
Drains must be desilted to their original depths from time to time so that the water table is 
kept to minimum level. Drains must be cleared of weeds growing in them so that flow of 
water is not hindered and there is no overflow during heavy rainfall. 
108 
Plantation Roads 
Today, a road system, including those in the plantation, is an important part of the 
infrastructure. Movements of people, produces and vehicles must be fast enough so 
as to maintain all deliveries and schedules on time. A good road system is considered 
another sign of progress. 
Objectives of Road System in a Plantation 
The objectives of a well-planned and well-constructed plantation road system are to: 
• maximise the general efficiency of all activities undertaken by the 
plantation 
• facilitate communications 
• facilitate supervision of all field activities 
• facilitate transportation of people, goods and materials within the plantation 
and the outside connections 
• reduce travelling time within the plantation 
• reduce production cost of the plantation 
Categories of Plantation Road 
In large plantation companies, normally, there are three categories of roads. They are: 
• The main road - connecting the main or parent plantation or 
headquarters and the normal public road 
• Subsidiary road - connecting the headquarters with the various 
divisions 
• Minor road - connecting field blocks in the plantation with 
the headquarters. 
The above road categories do not always exist in all plantations. Sometimes, 
there are two categories and at other locations, only one, depending on the size of the 
plantation. For example, a small plantation will only have two categories of road - the 
main and the minor roads, while a 3-ha smallholding within a smallholding community 
may not have any road at all, as it does not need one. 
109 
Construction of Plantation Road 
In planning for road system in a plantation, care should be exercised in the economic 
aspects of its constructions and usage, ensuring at the same time, it gives maximum 
benefit. The main road is the most expensive one and must therefore be as short 
as possible. The others are constructed according to their suitability. As far as 
possible, roads passing through steep hills, ravines or swamps should be avoided. 
The steepness of the slope where a road is to be constructed should not exceed 1 in 
30 or 2°. This is very critical, as most plantation roads only have gravel surfaces and 
therefore are easily eroded. All corners must be wide enough for maximum safety. 
On hilly terraced areas, roads must be made to cut as many terraces as possible to 
facilitate collection and transportation of crops such as latex. The width of plantation 
road should be 4-7 m and its total length per hectare is approximately 25 m for flat 
and 75 m for hilly areas. 
Road surfaces must be strong enough to support vehicles running on them. 
Laterite soil or sand is used as dumpings for road surfaces, which must have a 
thickness of 15 cm after pressing and in two layers. If the roads are going to be 
frequently used by vehicles such as tankers, stronger dumping material, for example, 
granite must be used and they must be pressed several times to obtain even and 
smooth surfaces. Road surfaces must always be dry. Drains along both sides must 
be constructed at reasonable depth to channel off water from the road surfaces. 
There must also be outlets for the drained water. Road surfaces must be constructed 
cambered towards the centre at 1 in 30 or 2°, so that surface water can be quickly 
drained to the sides (Figure 4.5). Laterite roads can easily be destroyed by water. In 
order to overcome this, bitumen is poured over them, in which case, the laterite layer 
below them should not contain more than 30% clay to avoid too much water being 
retained in the soil. 
I 
Road shoulder Side drain 
1 . 1 
"4-7 m * 
60 cm 60 cm 
Figure 4.5 Cambered road surface 
110 
Road Maintenance 
Roads must always have good surfaces. From time to time, they should be graded and 
pressed. This must be carried out when the surfaces are slightly moist. The cambered 
condition of road surfaces must always be maintained. Potholes in bitumen-surfaced 
roads must be patched up as they appear. The side drains must be regularly serviced. 
RUBBER PLANTING DESIGN 
Rubber planting requires a design or arrangement to portray rubber as a plantation 
crop. Well-arranged planted crops facilitate the task of locating and monitoring them 
when required, while at the same time they are pleasant to look at. A design is also 
required to determine whether the plantation is intended for other usage such as mixed 
or inter-croppings. 
A planting design consists of three components - crop density, planting distance 
and purpose it is intended for. From studies previously carried out by the RRIM, 1 ha 
is suitable for planting 400-500 rubber trees. For the purpose of balancing tapping 
cost and yield, as in the estates sector, up to 400 trees can be planted, while in the 
smallholdings sector where tapping cost is of no importance, up to 500 trees per hectare 
can be planted. These trees are spread evenly over the 1 ha area, and by arranging 
them in a well-planned design, the above objectives can be achieved. Thus, planting 
distances can be designed to provide such densities. There are several to choose 
from, and each depends on its purpose. Whatever the design chosen, the rule is that 
the distance between trees should not be closer than 2 m, except for experimental 
purposes. Table 4.7 provides several planting designs with various planting distances 
to achieve a density of 400-500 per hectare and a summary of their purposes. 
However, it should be noted that, for the hilly areas, only avenue-shaped design 
is recommended. This is because, on hilly areas terracing is required, and where 
possible, such heavy work operations should be kept to the minimum. Again, as trees 
grow bigger and taller, closer inter-rows may cause over-crowded conditions for trees in 
the lower and upper terraces. 
If the planting distances are known, planting densities per hectare can be 
calculated by using the formula shown overleaf. 
111 
TABLE 4.7 RUBBER PLANTING DESIGN 
Design 
Inter-
row 
distance 
(m) 
Inter-
tree 
distance 
(m) 
Area 
per tree 
<mJ) 
Density 
per 
hectare 
Remaks 
Square 4.50 4.50 20.25 494 • Regular crown development and well-balanced crown 
4.75 4.25 20.19 495 • Early shading of the ground surface, thus early suppression of weeds 
5.00 4.00 20.00 500 • Longer planting point distance - more maintenance of planting row and longer 
walking distance during tapping 
• Eariy shading , thus shortened period for inter-cropping 
Rectangular 5.25 3.75 19.69 509 • Shorter planting rows - thus less maintenance of planting rows and shorter 
5.75 3.50 20.13 497 walking distance during tapping 
6.25 3.25 20.31 492 • Late shading of ground surface, thus longer period for inter-cropping 
6.75 3.00 20.25 494 • Late shading of ground surface, thus late suppression of weeds 
• Irregular crown development resulting in less balanced crown 
Avenue 7.25 2.75 19.94 502 • Shorter planting rows - less maintenance of planting rows and 
8.00 2.50 20.00 500 shorter walking distance during tapping 
8.75 2.25 19.69 508 • Later shading of ground surface, thus longer period for inter-cropping 
• Irregular crown development, resulting in less balance crown 
Hedge 9.00 2.25 20.25 494 • Later shading of ground surface, thus late suppression of weeds 
10.00 2.00 20.00 500 • Very short planting rows, thus less maintenance of planting 
rows and shorter walking distance during tapping 
• Very irregular crown development resulting in imbalanced crown* 
• Very late shading of ground surface, thus longer period for inter -cropping 
• Also suitable for mixed cropping with other perennial crops 
Double Hedge 25 2.00" 6.32 400 • Further reduction in rubber planting row distance thus further reduction in its 
maintenance of the rubber rows 
• Specially designed for mixed cropping with other perennial crops 
TABLE 4.7 RUBBER PLANTING DESIGN (Contd.) 
Design 
Inter-row 
distance 
(m) 
Inter-tree 
distance 
(m) 
Area 
per tree 
(mJ) 
Density 
per 
hectare 
Remaks 
Triangular 
or 
Quincunx 
4.2 4.85 20.37 491 • Very regular crown development, resulting in very-well-balanced crown 
• Very early shading of ground surface, thus very early suppression of weeds 
• Longer planting rows, thus more maintenance of planting rows and 
longer walking distance during tapping 
• There is maximum utilisation of land in this design 
* If low height short term inter-crops are practised 
** Distance between trees in the triangle 
For square, rectangular, avenue and single-hedge planting design: 
Planting 
Density 
Area per hectare (m2) 
Area per tree (m2) 
Area per hectare 
Area per tree 
10, 000 m 2 
Row distance x tree distance 
Example: 
Distance between planting rows = 
Distance between trees = 
Area per tree = 
Density per hectare = 
• For double-hedge planting design: 
5 m 
4 m 
5 x 4 
10.000 m 2 
20 m 2 
Planting _ 
Density 
Area per hectare 
Area per tree 
Area per hectare (m2)
 x o 
Area per tree (m2) 
= 20 m 2 
= 500 trees 
10,000 m 2 
Row distance x tree distance 
Example: 
Distance between planting rows = 
Distance between trees = 
Area per tree = 
Planting density per hectare = 
• For triple-hedge planting design: 
25 m 
2 m 
25 m x 2 m 
10.000 m 2 
50 m 2 x 2 = 
50 m 2 
400 trees 
Planting _ 
Density 
Area per hectare 
Area per tree 
Area per hectare On2) 
Area per tree (m2) x 3 
10, 000 m 2 
Row distance x tree distance 
Example: 
Distance between planting rows 
Distance between trees 
Area per tree 
Planting density per hectare 
31 m 
2 m 
31 m x 2 m 
10.000 m 2 
62 m 2 
x 3 = 
62 m 2 
484 trees 
114 
For triangular or quincunx planting design: 
Planting 
Density 
_ Area per hectare (m2) 
Area per tree (m2) 
Area per hectare 
Area per tree 
10,000 m 2 
Row distance x tree distance x 0.866 
Example: 
Distance between trees in the triangle = 
Distance between planting rows = 
Area per tree = 
5 m 
5 m x 0.866 
5 m x 4.33 m 
4.33 m 
21.65 m 2 
Planting density per hectare 10.000 m
2 
21.65 m 2 462 trees 
FIELD LINING 
Lining is fixing of points in the field where planting is to be carried out. There are two 
types of lining - straight lining for flat areas and contour lining for hilly areas. Details of 
these are given in the following: 
Straight Lining 
Before lining work is carried out, lining equipment must be prepared. They are guide 
poles, planting pegs, lining ropes, a 30-m measuring tape and a prismatic compass. A 
straight lining can be of square, rectangular or triangular design. 
Square and rectangular design. Assume that ABCD (Figure 4.6) is the area 
to be lined with a planting distance of 5 m x 4 m to obtain a density of 500 points per 
hectare. The longest straight boundary (AB) is used as the base line where guide poles 
are fixed at 5 m intervals. At both ends of the base line (i.e. E & F) right angles are 
marked using the prismatic compass or the measuring tape. The adjacent arms of the 
rectangle are extended towards CD using the lining ropes. At the same time planting 
pegs are fixed at each marking along the ropes. Another rectangular-shaped area is 
almost created within ABCD. Its fourth side GH can be obtained by measurements 
along the lining ropes. Guide poles are also fixed at 5 m along GH. A lining rope is then 
stretched across to meet the corresponding guide poles along EF and GH. Planting 
pegs are fixed at markings along the lining rope. The lining rope is then shifted to the 
next corresponding guide poles and the same procedure is repeated. This is continued 
115 
until the whole of EFGH has been lined and pegged. Areas outside EFGH are also lined 
and pegged by extending the lines already made from EFGH. When completed, all the 
guide poles are removed and replaced with planting pegs (Figure 4.6). 
Figure 4.6 Square planting design 
Triangular or quincunx. Assume that ABCD (Figure 4.7) is the area to be lined 
with a planting distance of 4.8 m x 4.16 m (which is the perpendicular height of the triangle) 
to obtain a density of 500 points per hectare. Again, the longest straight boundary (AB) is 
used as the base line, where guide poles are fixed at intervals of 4.8 metres. At suitable 
both ends of the base line (A and E), 60° angles are marked using the prismatic compass 
or the measuring tape. The arms of these angles are then extended towards CD using 
the lining ropes. At the same time, planting pegs are fixed at each marking along the lining 
ropes. A parallelogram-shaped area is almost formed within ABCD and its fourth side or 
boundary (FC) can be obtained from the measurements marked along the lining ropes. A 
lining rope is then stretched across to meet the corresponding guide poles along AE and 
FC. Planting pegs are fixed at markings along the lining rope. The lining rope is then 
shifted to the next corresponding guide poles and the same procedure is repeated. This is 
continued until the whole area (AECF) is lined and pegged. Areas outside AECF are also 
lined and pegged by extending the lines already made from AECF. When completed, all 
the guide poles are removed and replaced with planting pegs (Figure 4.7). 
116 
Figure 4.7 Triangular planting design 
Contour Lining 
Equipment such as guide poles, planting pegs, a 30-m measuring tape and a levelling 
instrument are used for contour lining. The planting distance to be used is 8 m x 2.5 m to 
obtain a density of 500 points per hectare. For contour lining of a hilly area, the base line 
is laid from the peak to the foot and where the slope is average, by fixing a guide pole, 
one at the top and another at the base, and stretching a string to meet the two points. The 
contour interval of 8 m is the horizontal (YX) and not the surface (ZX)distance (Figure 4.8). 
It is therefore essential to determine first, the gradient of the slope where the base line 
has been laid. When the gradient is known, the surface distance between contours can 
be calculated by the mathematical cosine rule, in which the four-figure logarithmic table or 
equivalent has to be referred to. 
Figure 4.8 Determining the inter-contour distance on a hill slope 
117 
AB is the line of average slope (base line) 
Assume that its gradient 
XY (the fixed horizontal distance 
1 in 2 (18°) 
8 m 
XZ (surface distance between contours) = XY 
Consine X 
8 m 
Consine 18° 
8 m 
0.9511 
8.41 m 
Starting from the top, guide poles are then fixed at intervals of 8.4 m along the 
base line. Plotting the contour line is done from the top of the hill, starting at the second 
guide pole, using either the road tracer, Abney level, clinometer the hurdle-mounted 
spirit level or any other levelling instruments. 
Road tracer method. The road tracer is placed upright at the guide pole with 
its telescope facing the side of the slope. The sighting board is placed in front of the 
telescope at a convenient distance, say, 10 m from the guide pole. Eyeing through the 
telescope, the centre point on the sighting board is located. When the centre points 
in the telescope and on the sighting board are aligned, both the road tracer and the 
sighting board are standing at points of the same level. A planting peg is fixed at the foot 
of the sighting board. If the two centre points are not aligned, the sighting board should 
be shifted either up or down hill until they are level. The road tracer is then moved to the 
planting peg which has just been fixed, followed by the sighting board 10 m in front of it, 
and the same procedure is repeated until a number of planting pegs are seen fixed in a 
line, each 10 m apart. This is known as a contour line, as it is not straight, following the 
curves and bulges of the slope. This line is continued until it meets the boundary of the 
area, or if the area is a full hill, the contour line should meet at the starting point, where 
the guide pole is fixed. When a contour line is completed, the road tracer is shifted to 
the next (lower) guide pole and the same procedure is repeated until the entire hill area 
is contour-lined and pegged. If at any part of the slope, the contour lines are closing 
up by less than half (less than 4.2 m) the distance between contour lines, the plotting is 
stopped. But when the contour line opens up or becomes wider at more than one and 
a half (more than 12.6 m), a contour line is filled in between them, and this is known 
as a blind contour. The guide poles are then removed and replaced with planting pegs 
(Figure 4.9). 
118 
Figure 4.9 Contour lining a hilly area - a plan of the contoured hill (above) and 
cross-section of the same hill (below) 
Hurdle-mounted spirit level method. One leg of the hurdle is placed at the guide 
pole and the other one is moved slightly up or down hill until the air space in the spirit 
level fluid is centred. This indicates that both the hurdle legs are standing at points of 
the same level. A planting peg is then fixed at the second leg. The hurdle is then shifted 
with one leg now at the planting peg and the other moved until a level is indicated by 
the instrument. Another planting peg is fixed at the third point of the same level. This 
procedure is continued until the contour line meets the boundary. If the area is the 
whole hill, the contour line should meet at the starting point. The hurdle is then shifted 
to the next (lower) guide pole and the above procedure is repeated until the entire area 
is contour-lined and pegged. A contour line is discontinued when it converges with the 
upper one at less than half (less than 4.2 m) the distance between contour lines. A 
blind contour line is filled in where the contour lines open up at more than one and a half 
(more than 12.6 m) the distance. All the guide poles are removed and replaced with 
planting pegs (Figures 4.9) 
119 
Guide poles can be made from straight rounded jungle poles of 3 cm in diameter 
and 2 m in length, and sharpened at the bottom end. Planting pegs are made from split 
bamboo stem of 1 cm in diameter and 1 m in length and sharpened at the bottom end. A 
lining rope is best made from rattan of 1 cm in diameter and 40-60 m in length. Planting 
points are marked along the lining rope. Other materials such as the manila rope and 
galvanised wire can also be used as lining ropes. The hurdle which is in the shape of 
the letter A (sometimes called the A-frame) is made from wooden beroties 5.0 cm x 2.5 
cm and 2.0-2.5 m in length with a crossbar made from the same beroti and is fixed parallel 
to the ends of the hurdle legs. The distance between the leg ends follows the distance 
between planting points, in which case 2.5 metres. The spirit level is fixed at the centre of 
the crossbar (Figure 4.10). 
(a) Road tracer and sighting board (b) Hurdle (A-frame) and spirit level 
Figure 4.10 Contour lining equipment 
PLANTING PERIMETER FENCING 
A fence can be considered as an impediment; placed or laid along the boundary of a 
plantation. There are several types of plantation fencing, but the most common is the 
barbed wire fixed on posts. 
120 
Objectives of Plantation Perimeter Fencing 
Erecting a perimeter fence along the plantation boundary has several objectives, and 
the main ones are to: 
• demarcate the plantation boundary 
• avoid any dispute with regards to land ownership 
• keep away animal pests 
• provide protection to planted crops 
• ensure general security of the plantation 
Method of Erecting Fence 
Fences are usually erected after land clearing. All the boundary stones must first be 
located and clearly marked. A string is then stretched along the perimeter, meeting all 
boundry stones marked. Starting from one corner, points where fencing posts are to 
be planted are marked along the string at intervals of 2.5 metres. This ensures that 
the fence is straight and neat. The posts are made of hardwood timber such as resak 
of 7.5 cm x 5 cm x 210 cm in size or hardwood jungle rollers of 7.5 cm diameter and 
of 210 cm in length. The posts at all corners must be of similar type of wood, 7.5 cm x 
7.5 cm x 210 cm in size. The posts are buried 60 cm deep. At every eighth post and at 
all corners, supports are erected with the same type of wood of 7.5 cm x 7.5 cm x 210 cm 
in size. The pair of posts where the gate is to be erected should also be of the same size 
as the corner posts. All fencing wires are fixed from the outside. Normally, four strands 
of barbed wire are used, the first one at ground level, the second, third and the fourth at 
50 cm, 100 cm and 150 cm from the ground, respectively. The barbed wires must be 
pulled taut before nailing. To keep way small animals, wire netting of 3 cm mesh and 
100 cm in width is fixed at the lower section of the fence. At a suitable point along the 
fence, a gate is constructed for easy access into the plantation. 
PLANTING HOLE 
The initial growth of crops in the field starts from the planting hole. Large and very well 
made planting holes are expected to assist in spearheading the initial growth of crops. 
121 
Objectives of Holing 
Before any field transplanting of rubber is done, planting holes are prepared well ahead 
of time (Figure 4.11). The objectives of holing are to: 
• obtain a block of loose soil 
• facilitate root development at a critical stage 
• remove rocks and other hard materials which may be hidden in the soil 
• remove root disease source, if any 
• enable the weathering and seasoning of the planting hole 
• facilitate application of basal fertiliser (rock phosphate) 
• facilitate transplanting of rubber 
Method of Holing 
Planting holes are dug much earlier before planting to allow them to weather by sunlight 
and rain. Holes are dug at the planting pegs fixed during field lining, with the pegs used 
as the centre points of the planting holes. The soil dug out is placed as near to the brim 
of the holes as possible and in not more than two heaps. The top half and the bottom 
half of the soil from the hole should be separated. When completed, the planting pegs 
are fixed back into the centre of the holes. The minimum size of a planting hole is 60 
cm x 60 cm x 60 cm. Sixty manually-dug planting holes can be completed in a day. But 
when speed is necessary, cylindrical planting holes of 45 cm diameter and 45 cm deep 
can be dug mechanically. 
(a) Manually-dug planting hole (b) A mechanical digger (soil borer) 
is used at sloping areas 
Figure 4.11 Preparing planting holes 
122 
CHAPTER 5 
RUBBER PLANTING AND MIXED CROPPING 
PLANTING 
After allowing the planting holes to weather for about two to three weeks, transplanting 
activities can be carried out. Current technology requires the use of polybag buddings, 
either budded stumps in polybags, young buddings in polybags or the more advance-
aged core stumps prepared in the nursery, as planting materials. 
Objectives of Planting 
Other than developing a plantation of rubber crops, proper planting technique helps to: 
• initiate crop growth 
• achieve a high percentage of planting success 
• reduce replacement 
• maximise the use of potentially good planting materials 
• reduce plantation development cost 
Method of Planting 
A polybag budding is normally planted up to the base of the scion shoot or stem. It can 
also be planted much deeper, until one whorl of the scion is buried, which in normal 
growth, is up to 15 cm of the scion stem. This is known as deep planting. First, the 
polybag is placed upright in the planting hole to determine the correct depth. If it is 
not deep enough, it should be deepened and if it is too deep, it can be refilled to the 
required depth. The bottom of the polybag is cut away to expose the soil. The polybag 
is again placed upright in the centre of the hole. A vertical cut is made on the side of the 
polybag. The hole is refilled with the top half of the soil first. The cut polybag is then 
carefully pulled out. The hole is completely refilled with the rest of the soil after mixing it 
with 113 g rock phosphate. Only the soil around the brim of the hole is pressed to avoid 
damaging the roots. Mulching is then applied around the plant (Figure 5.1) 
123 
(a) Diagram showing depth of planting - normal (left) and deep (right) 
124 
(f) Press soil around the brim of the hole 
(g) Planting completed 
Figure 5.1 Planting polybag material 
125 
From experiments carried out, deep planting technique described earlier helps in the 
growth of rubber plants. Tables 5.1 and 5.2 show the effect of deep planting on growth 
rate of PB 255. 
TABLE 5.1 EFFECT OF DEEP PLANTING ON GROWTH OF 
YOUNG BUDDINGS OF PB 255 
Depth of planting (cm) Girth (cm) 
12 months 18 months 
0 9.0 12.2 
15 10.5 13.8 
TABLE 5.2 EFFECT OF DEEP PLANTING ON GROWTH OF YOUNG BUDDINGS 
OF PB 255 
Depth of planting 
(cm) 
Girth (cm) 
12 months 18 months 21 months 
5 4.7 8.3 11.2 
15 5.0 9.4 12.1 
In deep planting technique, covering of the green scion tissue with sandy soil 
type may cause scorching of the green bark. Therefore, a cavity should be left around 
the plant during planting, and allowed to be refilled by itself over time. 
To achieve good and healthy growth of plants, ensure that only good quality 
planting materials are transplanted into the field. The following are some guidelines: 
Plants are healthy 
Stem girths are of the same size 
Plants have at least two whorls of hardened leaves 
Plants are free from leaf diseases 
Polybags are not broken, the soil cores are still intact 
When transplanting rubber into the field, it is advisable to plant out 10% extra 
materials, which can later be used as replacement. These can be planted along the 
normal planting strips after every tenth planting point in a density of 500 point per 
hectare. Alternatively, they can also be planted in the inter-rows. 
126 
MULCHING 
Mulching can be defined as providing (not by growing) cover to the soil surface, especially 
around the base of crops with whatever type of green litter and other materials. Mulching 
is recommended particularly on transplanted rubber crops. It is an old established farm 
practice, but its importance was only realised in recent years. 
Advantages of Mulching 
Several advantages can be obtained by applying this farm practice, and the important 
ones are that, it: 
• Protects Soil Surface From Direct Sunlight 
• Preserves Moisture In The Soil 
• Encourages Feeder Root Development In The Top Soil (Table 5.3) 
• Prevents Weed Growth 
• Reduces Soil Erosion 
• Improves Soil Structure 
• Adds Organic Matter To The Soil 
• Enhances Growth Of Rubber Crops (Table 5.4) 
TABLE 5.3 EFFECT OF MULCHING ON FEEDER ROOT DEVELOPMENT AND GROWTH 
OF MAXI STUMPED BUDDING CLONE RRIM 600 
Treatment Weight of feeder root within 0-15 cm of soil 
Girth increment at 
16-18 months (cm) 
No mulching 0.23 g/1000 cc of soil 7.2 
With mulching 1.02 g/1000 cc of soil 9.0 
TABLE 5.4 EFFECT OF VARIOUS TYPES OF MULCH ON GROWTH OF RRIM 600 
Type of mulch Girth increment (cm) (After 13 months) 
Control (no mulch) 6.6 
Oil palm kernel 7.3 
Oil palm fruit bunch 7.1 
Imperata cylindrica 7.1 
Coconut husk 6.7 
127 
Mulching Materials 
The following are some of the categories of material that can be used for mulching: 
• Plant litter such as Imperata cylindrica (lalang), empty palm fruit bunches, fruit skins, 
coconut husks, palm kernel. 
• Used packing materials such as fertiliser bags, cement bags, sugar bags and other 
polythene or paper wrappings. 
Usually such materials are regarded as worthless and often go into the rubbish dump or 
worse still, burnt. But they are assets to agriculture. 
Method of Mulching 
Mulching is recommended immediately after transplanting of rubber planting 
materials into the field. The mulching material is spread around the base of the crop to 
cover the soil at a radius of 30-60 cm with a thickness of five centimetres. A space of 
five cm should be left vacant around the plant base to avoid fungal growth. If packing 
• materials are used, weights should be placed at the corners to prevent being rolled up 
or blown away by wind. If paper bags are used they should be in four or five layers 
(Figure 5.2). 
Figure 5.2 Lalang grass (Imperata cylindrica) used as mulching material 
128 
MIXED CROPPING 
Mixed cropping under rubber is planting of rubber with other cash crops in the same area. 
It has been practised in a number of rubber-producing countries since 1930. In Malaysia, 
mixed cropping was said to have started during the Japanese Occupation (1942-1945) 
where the planters were forced to replace rubber with food crops to overcome shortage 
of food supply. However, some planters did not cut down the rubber trees, instead 
planted food crops in the inter-rows of rubber (Figure 5.3). This was the beginning of the 
practice of mixed cropping under rubber gradually diminished. Subsequently, however, 
low rubber prices encouraged rubber smallhoders to practise mixed cropping in their 
rubber holdings. This also enables them to obtain supplementary income, especially 
during the immature stage of rubber. 
Objectives of Mixed Cropping 
Mixed cropping of rubber with other crops has the following objectives, and they are 
to: 
• achieve maximum utilisation of limited land 
• diversify crops within a limited area 
• increase income from a limited area 
• avoid dependence of income from a single crop 
(a) Rubber + sugarcane + papaya 
129 
(b) Rubber + maize 
(c) Rubber + pasture + sheep 
Figure 5.3 Various types of mixed cropping 
130 
Method of Mixed Cropping 
In mixed cropping, rubber as the main crop is planted with other cash crops with 
a density of about 400 trees per hectare. To enable other crops to survive, the planting 
design is of three types, namely, single hedge, double hedge or triple hedge system. 
In such designs, the inter-row distances of rubber are very wide, while the inter-tree 
distances are very close. In the double and triple hedge designs, the inter-tree distances 
are not only close but the trees are arranged in triangular formation, with double and 
triple rows. In the wider inter-row spaces, other perennial crops are planted. 
Since the rubber trees are planted very close in the row, the irregular crown 
development may cause lopsided effect as the trees grow older. To avoid this, only 
clones suitable for close planting (less than three metres) such as RRIM 728, RRIM 
729, RRIM 805, RRIM 901, RRIM 905, RRIM 936, RRIM 937, RRIM 938, PB 217, PB 
260, PB 254, PB 255, BPM 24 and Nab 17 are recommended. Suggested perennial 
crops to be planted are durian, cempedak, mango, rambutan, duku and cocoa. Short-
term crops and pastures can also be included. However, the suitability of the crop 
chosen must first be determined before venturing into this system of planting. The local 
agricultural extension agents should be able to assist in this matter. Figure 5.4 shows 
suggested planting designs of various crop mixtures that can be cultivated with rubber. 
X X X X X X 
X X X X X ] 
X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X 
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X + 
3m | 
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X x = Rubber (400/ha) 
• - Cempedak, star fruit or other crops (200/ha) 
131 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
3m 
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X + 
6m 
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X-)-
3m 
x x i- " " • " " " V V V V V V X X X X X X X X X X X X X . X X X -
x = Rubber (400/ha) Durian (44/ha) 
• = Cempedak, star fruit or other crops (88/ha) ^ 
x x x x x x x x x x x x x x x x x x x x XX x x x x x x x x x 
'2 m' 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x -
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x-f-
3m 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x = Rubber (400/ha) Pasture or cash crops 
« = Cempedak, rambutan, duku or other crops (66/ha) 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x X-
2 m 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x ^ 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
X X y v v v v v x x x X X X X X X X X X X X X X X X X X X X - l -
x •£ Rubber (400/ha) Pasture or cash crops 
• = Cempedak, rambutan, duku or other crops (66/ha) 
132 
XXXXXXXX, X X X X X X X X X X X X X X X X X X X X X X X 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
22m 
x r x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x = Rubber (400/ha) Pasture or cash crops 
3m 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
+ • + • + • + • + • + • + • + + • + • + • + • + • + • + 
• + • + • + • + • + • + • •+ • + • + • + • + • + • + • + • + af 
3m 
|3.5ro 
3m 
3 m 
3 m 
3 ro 
3 m 
|3J m 
3m 
fl 
+ • + • + • + • + • + • + • + • + • + • + • + • + # + • + »+• 
* * *•* 9 m—»•* * * * 
• + • + • + • + • + • + • + • + • + • + • + • + • + • + • + .4-
• + • + '• + • + + 
* * * * * * * " it m* * + * "^2*m"^  * + * + * 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x = Rubber (400/ha) + = Banana (800/ha) 
p c x x x x x x x x x x x x x x x x x x x x x x x x x x x x x r 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
I x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x i 
. -9m-
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x-L 
Rubber (400/ha)
 L | ' ' T = Pasture or cash crops 
3m 
3m 
133 
x x x x x x x x x x x x x x x x x x y x x x x x x x x x x x -
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x -
I x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
( x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x - ! 
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 
t x x x x x x x x x x x x x x x x x x x x x x x x x x x x x xJ 
x - Rubber (480/ha) 
_ *_•=• .Cempedak, rambutan or other crops (53/ha) 
'.'.',** Cash crops 
IX XXXXXXXXXXXXXXXXX XX XXXXXXXXX Xi 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX-] 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX X-
X XXXXXXXXXXXXXXXXXXXXXXXXXXXXX^ 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX XJ 
6m 
6.5n> 
Rubber (480/ha) 
: Cempedak, duku, star fruit or other crops (160/ha) 
XXXXXXXXXXXXXXXX XX XXXXXXXXXXXJ 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX X-
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX-j 
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX-
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX-
x
 Bi Rubber (480/ha) Durian (35/ha) 
» » Cempedak, duku, star fruit or other crops (70/ha) 
Figure 5.4 Various mixed crop planting designs 
134 
(b) Two rubber rows with fruit trees on undulating ground 
(c) Three rows of rubber trees with fruit trees planted in the 
inter-cropping area at 25 m distance 
Figure 5.5 Different types of hedge planting 
135 
POINT PLAN 
A point plan can be defined as a plan of the plantation area showing its topography, 
planting rows, terraces, crop points, buildings and infrastructure such as roads, paths, 
rivers, streams, bridges and culverts. A point plan is an aerial view of the plantation. 
Objectives of Point Plan 
The objectives of having a point plan of a plantation are to: 
• have a good knowledge of the general condition of a plantation 
• know the location of the plantation including the planted crop, buildings and 
infrastructure without going to the field 
• utilise it as office record 
• facilitate field maintenance work such as manuring, weed control and others 
• facilitate monitoring of field operations 
• facilitate the allocation of tapping tasks when the trees reach maturity 
• facilitate plantation planning and budgeting 
• assist in research and development activities 
Drawing-up a Point Plan 
To draw up a point plan of plantation, a topography map of the area must first 
be obtained from the Survey and Mapping Department. Two boundary plans of the 
plantation are drawn on graph papers. To facilitate this, one has to refer to the plan 
illustrated in the title grant. The topography of the plantation is marked out on the 
plan. This can be copied from the topography map. Then go to the field and mark 
out roughly on the plan the locations of the planting rows, terraces, trees or plants, 
buildings and all the infrastructure. The exact measurements of the above must be 
taken. Transfer all the recordings made in the field on to the spare plan with their exact 
measurements. In addition, it is also useful to show the neighbouring land conditions, 
even if they do not belong to the same owner, and other nearby landmarks. It is also 
important to indicate the north sign. Recordings on the plan should be made with 
signs and symbols to save space, with their explanations given at one corner of the 
plan sheet. Some examples of suggested signs are given in Table 5.5. 
136 
TABLE 5.5 SUGGESTED SIGNS FOR POINT PLAN RECORDINGS 
Content of plantation Suggested sign 
Topography Colour shading 
Public road Bold black line 
Plantation road Ordinary black lines 
River/stream Ordinary double lines 
Bridge/culvert Double brackets facing outwards 
Building Diagram of building 
Planting point (straight) Equidistant dots in a straight line 
Planting point (terrace) Equidistant dots along a contour line 
North Arrow pointing north 
Note: Any sign or symbol can be used as long as the explanation is provided 
Figure 5.6 A sample point plan of a rubber plot 
137 
For a large area, the making of a point plan is difficult as it requires a large sheet and 
drawing board. This can be overcome by breaking-up the area into several blocks. 
The criteria for demarcating the blocks can be rivers, streams, roads or hills. The point 
plan can then be made block by block. All entries made must be checked for accuracy 
by going back to the field, and alterations made where necessary. Again back on the 
drawing board, the point plan is copied on to a tracing paper. The point plan can be 
completed by additional information such as hectarage, date of planting, clones used, 
planting distances, densities and so on. If the point plan has been divided by blocks 
during preparation (due to its large size), the separated sheets can be joined to form a 
single point plan for the whole plantation. A sample point plan is given in Figure 5.6. 
138 
CHAPTER 6 
FERTILISER APPLICATION AND FIELD MAINTENANCE 
All plants including rubber require adequate amount of water, light, carbon dioxide and 
nutrients for growth to their maximum potential. A shortage or an excess of one or 
more of these elements, the presence of disease or extreme climatic conditions cause 
reduction in growth, yield and the quality of the crop produce. Water, light, and carbon 
dioxide are naturally available, however, nutrients are added by fertiliser application. 
FERTILISER AND ITS FUNCTION 
Fertiliser is defined as a substance that provides nutrients to plants for their growth to 
enable it to function well. Plants like rubber respond favourably in terms of growth and 
yield to adequate and proper fertiliser application. Among the elements, the major ones 
are nitrogen (N), phosporus (P), potasium (K) and magnesium (Mg). 
N is essential for the formation of plant tissue, plant protein and chlorophylll. P 
is necessary for nucleic acid structure, phospholipids, assimilation and respiration of 
plants. K is required for assimilation of protein, carbohydrate as well as lipid, while Mg is 
necessary for chlorophylll development. Other elements needed in micro quantity are 
sulphur (S), calcium (Ca), iron (Fe), manganese (Mn), molybdenum (Mo), copper (Cu), 
boron (B), zinc (Zn), nickel (Ni) and chlorine (CI). 
TABLE 6.1. EFFECT OF FERTILISER ON GROWTH OF TWENTY SEVEN 
MONTHS OLD RUBBER 
Treatment Girth (cm) 
No fertiliser 18.2 
With NPKMg fertiliser 23.2 
TABLE 6.2. EFFECT OF NITROGEN ON YOUNG RUBBER 
ON SELANGOR SERIES SOIL 
Treatment Girth (cm) Trial 1 Trial 2 
Ammonium sulpate 52.95 45.13 
Urea 53.58 44.57 
SE (±) 0.591 0.913 
P< 0.05 1.79 2.17 
139 
TABLE 6.3 EFFECT OF PHOSPHORUS ON GROWTH OF RUBBER 
Treatment Girth (cm) 
Without phosphorus 48.4 
With phosphorus 52.4 
TABLE 6.4 EFFECT OF UREA ON GIRTHING RATE OF RUBBER AT 160 CM HEIGHT 
Treatment Yearl Year 2 Year 3 Year 4 
N1 F1 14.2 28.4 40.2 49.1 
N1 F2 14.0 28.3 40.3 50.3 
N1 F3 14.7 29.4 41.4 50.4 
N2 F1 15.2 29.9 42.5 52.2 
N2 F2 11.3 24.7 36.8 45.4 
N2 F3 14.2 28.1 40.3 50.2 
Mean 13.9 28.1 40.3 49.6 
Control 10.9 23.5 35.5 46.0 
Note: 
N1 UREA F1 1X 
N2 Mix F2 2X 
Control None F3 4X 
TABLE 6.5 EFFECT OF DIFFERENT SOURCES OF PHOSPHATE ON GIRTHING RATE OF 
RUBBER AT 160 CM HEIGHT 
Treatment Year 2 Year 3 Year 4 Year 5 Year 6 Increment 
Control 17.7 27.8 34.0 39.1 44.3 26.6 
CIRP 19.6 30.0 36.7 41.9 44.9 25.3 
CHINA 18.5 28.3 34.8 38.4 42.9 24.4 
GAFSA 18.8 28.7 35.2 40.0 43.5 24.7 
Mean 18.7 28.7 35.2 39.9 43.9 25.25 
* Fertiliser applied as Mix Mag X and Mag Y after 36 month 
140 
TABLE 6.6 EFFECT OF FERTILISER ON BARK RENEWAL 
Treatment Bark thickness at third year (mm) 
Without phosphorus 5.2 
With phosphorus 5.3 
Without potassium 5.1 
With potassium 5.4 
In general,adequate and proper fertiliser application will: 
• encourage good growth in favour of early tapping 
• increase latex production and wood volume 
• provide early canopy closure that grants shade and retards undergrowth thereby 
reduces cost of weeding 
• promote good renewed bark 
• provide protection against diseases 
Optimum Use of Fertiliser 
The optimum use of fertiliser can be defined as an approach whereby the right quantity 
of fertiliser application to plants that ensures positive economic impact to the farmer and 
minimum loss of nutrients to the environment. 
Factors that should be considered into before fertiliser application is carried out are: 
Type of soil - Soil is classified according to physical and chemical characteristics. 
Physical characteristics consists of soil structure (e.g. soil aggregate), soil texture 
(e.g. sandy, clayey), moisture and soil aeration. Soil chemistry includes soil nutrients, 
pH, organic matter content and cation exchange capacity. Knowledge on soils help in 
proper fertiliser application management as different class of soil responds differently 
to fertilisers. 
Type of fertilisers - There are three types of fertilisers namely straight, mixture and 
compound. Straight fertilisers provide one type of nutrient while mixture and compound 
fertilisers provide two or more nutrients. Compound fertilisers are better as they are 
uniform in the ratio of elements required. Both mixture and compound fertilisers can be 
used for rubber if the ratio of N, P, K and other elements are appropriately prepared for 
rubber trees. 
141 
Rate and amount of fertiliser - For good response, the rate of fertiliser application 
should be in accordance to the amount and type of fertiliser recommended. The 
recommended rate and amount of fertiliser for young rubber is given in Table 6.11. 
Zone of fertiliser application - Fertilisers should be applied to the feeder root zone 
for maximum uptake of nutrients. For young and small trees, fertiliser application is 
confined to the small circle area under the canopy while for mature trees; fertiliser is 
applied between the rows or inter-row (Figure 6.5). 
Depth of fertiliser application - Fertilisers can be applied by broadcasting, or 
incorporated with soil depending on suitability. Loss of fertiliser by erosion or volatilisation 
can be reduced if fertiliser is incorporated with the soil (Figure 6.2). 
For mature trees, Discriminitory Fertiliser Recommendation is recommended based on 
the following: 
• nutrient status of the trees and soil 
• results from experiments 
• additional information such as history of fertiliser application, clone, yield and 
wind damage susceptibility 
• recommendation is for a period of two years 
Time of fertiliser application - The uptake of nitrogen by rubber trees is most active 
at the commencement of refoliation up to five months thereafter. Rate of uptake is 
positively correlated with the emergence of new leaves. 
Fertiliser is recommended to be applied after refoliation. In general, one kg/tree of 
fertiliser need to be applied. It is advised to split the application whereby the second 
application should be before June. For sandy areas, it is advised that fertiliser is applied 
as split applications twice or more in Feb/Mar and May/June. 
In area where clones are susceptible to wind damage, reduced canopy is required to 
avoid trunk snap. 
• Amount of fertiliser need to be adjusted in wind damage prone areas. Rate of 
nitrogen should be reduced 
• Fertiliser application is carried out during wintering 
• If the risk of wind damage is high, avoid fertiliser application during wintering 
but to be applied before June 
142 
• Reduce the amount of fertiliser to half of the recommendation. This is 
because there is less uptake of nutrients for a period of three to four months 
after refoliation. 
Fertiliser Application for Stimulated Trees 
For trees that have been stimulated either using ethephon or ethylene gas, extra fertiliser 
is needed to compensate the loss of nutrients owing to increase in latex production. 
For every 1,000 kg/ha of dry rubber, 11 kg of N and 12 kg of K 2 0 is needed. This 
is equivalent to 55 kg of Ammonium Sulphate and 25 kg of Muriate of Potash for every 
hectare of rubber. 
Nutrients 
All living plants need nutrients which are available in fertilisers. Plant nutrients can be 
divided into three groups (Table 6.7). 
TABLE 6.7 PLANT NUTRIENTS 
Group Classification Nutrients 
A Essential Carbon 
Hydrogen 
Oxygen 
B Major Nitrogen 
Phosphorus 
Potassium 
Magnesium 
Calcium 
Sulphur 
C Minor or trace Manganese 
Copper 
Boron 
Iron 
Zinc 
Molybdenum 
Chlorine 
143 
The total number of nutrients required by plants is sixteen. Plants obtain 
nutrients of elements in group A from the air and water, and are usually sufficient, 
except when large fires or long droughts occur. They are classified as essential 
because no plant can exist without them. Nutrients in group B are known as major 
nutrients or elements a s they are required by plants in large quantities, and are 
supplied through fertilisers. Nutrients in group C are also required by plants, 
though in small quantities. Plants usually exhibit nutrient deficiency on the leaves. 
Analysis of the leaves and soil can confirm this. In fact manuring of planted crops 
based on such analysis is most effective. This is known as discriminatory fertiliser 
application. 
Functions of Major Nutrients 
Nitrogen is very important for plant growth as it is a constituent of a proteins, 
protoplasm and chlorophyll, thus it helps in left development are thereafter 
photosynthesis. Phosphorus is important in plant cell divison and the development 
of meristematic tissues, thus it assists in root development. 
Potassium plays an important part in plant metabolism and in the overall 
growth of plants. Magnesium is important in photosynthesis as it is a constituent of 
chlorophyll. Calcium is also a constituent of the cell, that is the middle lamella and 
also important in root development. Sulphur is also a constituent of all proteins and 
it is also associated with the formation of chlorophyll, although not its constituent. 
Nutrient Deficiency 
Usually, a plant deficient of nutrient exhibits its symptoms on the leaves. Insufficient 
nitrogen is indicated by the pale green and later total yellow. Phosphorus deficiency, 
is characterised by the underside of the leaf becoming brown in colour beginning 
from the tip. When the leaf margin becomes yellow, it shows that the plant is 
deficient in potassium. When the spaces between the leaf veins turn pale yellow 
in colour and the veins look like herring bones. When the leaf tip and leaf margin 
appear scorched turning white to brown in colour, calcium deficiency is indicated. 
Deficiency in sulphur, which is quite common in young leaves, results in the leaf 
becoming pale green and smaller in size, and after something necrosis of the leaf 
tip and margin occurs (Figure 6.1). 
144 
(a) Nitrogen deficiency 
(b) Phosphorus deficiency 
(c) Potassium deficiency 
(d) Magnesium deficiency 
(e) Calcium deficiency 
(f) Sulphur deficiency 
Figure 6.1 Major nutrient deficiency symptoms in rubber leaves (first leaf from the left is not deficient) 
146 
Types of Fertilisers 
Fertilisers can be grouped into two - organic and inorgnic. Organic or natural fertilisers 
originate from plant and animal organs including their excretions. When they decompose 
they become fertilisers to the living plants. Inorganic fertilisers are synthesised by 
chemical process, and are available in three forms, namely, straight, mixture and 
compound fertilisers. Details concerning them are given in the following text. 
Straight (single) fertilisers. When a plant is deficient in a particular nutrient a straight 
fertiliser containing that particular nutrient is applied to the plant to rectify the problem. 
Generally, straight fertilisers contain only one nutrient, there are some containing one 
major nutrient with one or two minor ones. Examples of some straight fertilisers are 
found in Table 6.8. 
TABLE 6.8 EXAMPLES OF STRAIGHT FERTILISERS 
Fertiliser Form 
Nutrient content (%) 
N P O K 20 CaO MgO 
Ammonium sulphate Crystal 21 
Ammonium nitrate Crystal 35 
Ammonium chloride Crystal 26 
Calcium ammonium nitrate Crystal 21 
Calcium cynamide Powder 21 
Sodium nitrate Crystal 16 
Nitro 26 Granule 26 
Urea Crystal 45 
CIRP Powder - 36 - 50 -
FRP Powder - 36 - 42 -
NARP Powder - 27 - 42 -
Single superphosphate Crystal - 16-18 - - -
Double/triple superphosphate Crystal - 46 - 10 -
Ammonium phosphate Crystal 11 48 - - -
Diammonium phosphate Crystal 21 53 - - -
Basic slag Various - 18-19 - - -
Potassium chloride (Muriate of 
potash) Crystal - - 61 - -
Potassium sulphate 
(Sulphate of potash) Crystal - - 50 - -
Potassium magnesium sulphate Crystal - - 29 - 9 
Magnesium sulphate (Kieserite) Crystal - - - - 26 
Magnesium limestone (Dolomite) Powder - - - 30-35 20 
Calcium carbonate Powder - - - 54-56 -
147 
There are mainly two forms of straight fertilisers, namely, crystals and powders. 
The crystal form of fertilisers are easily soluble in water, and quickly absorbed by 
the roots. However, under tropical conditions, it is highly volatile or easily leached. 
Fertilisers in the form of powders are not readily soluble and take much longer time to 
be absorbed by the roots, but are not volatile and can provide cumulative effect to the 
soil. 
Mixture fertilisers. Mixture fertilisers are made up of more than one straight fertilisers 
mixed together by physical means. Usually, mixture fertilisers contain only nitrogen, 
phosphorus, potasium and magnesium (NPKMg). Other special formulations can also 
be produced on request, as they can be easily prepared by simple physical mixing. 
RRIM mixtures are rock phosphate-based and formulated specially for use on rubber 
(Table 6.9), while the Nutrex mixtures are soluble phosphate-based. 
TABLE 6.9 RRIM-FORMULATED MIXTURE FERTILISERS 
Formulation (% nutrient) 
Type Ammonium 
Sulphate (N) CIRP (P 20 5) 
Potassium 
chloride (K.O) 
Magnesium 
sulphate (MgO) 
Magnesium M 42* (8.8) 45* (16.2) 5* (3-0) 8* (2.1) 
Magnesium X 40* (8.4) 40* (14.4) 12* (7-2) 8* (2.1) 
Magnesium C2 62* (13.0) 24* (8.6) 6* (3.6) 8* (2.1) 
Magnesium Y 51* (10.7) 29* (10.4) 12* (7.2) 8* (2.1) 
Magnesium J 41* (8.6) 30* (10.8) 21* (12.6) 8* (2.1) 
MM1 50* (10.5) 18 3/4* (6.8) 15 5/8* (9.4) 15 5/8* (4.1) 
W1 27* (6.0) 42* (16.0) 31* (20.0) -
W2 34* (8.0) 42* (16.0) 24* (16.0) -
J 45* (9.5) 33* (11.9) 22* (13.2) -
Y 56* (11.8) 30* (10.8) 14* (8.4) -
'Parts per hundred by weight 
Compound fertilisers. Compound fertilisers are made up of two or more straight 
fertilisers compounded by chemical process. They are usually in granulated form. 
Several brands are available in the Malaysia market such as CHB, FPM, Behn Meyer, 
Superfos, Complasel and BASF compounds. 
148 
Slow release fertilisers. During the last few years, slow release fertilisers were 
introduced into the Malaysian market (Table 6.10). The advantages of this type of 
fertilisers are that they last longer in the soil and thereby reduce the frequency and 
labour of fertiliser application. They have been tried on rubber and look promising. 
TABLE 6.10 SOME SLOW RELEASE FERTILISERS 
Type 
Approximate period 
of nutrient release 
(month) 
Nutrient content (5%) 
N P K MgO 
IBDU Woodace No.4 12-36 12 6 6 2 
Kokei Field King 12-24 14 8 6 5 
Greenpile 10-12 17 10 10 -
Monsoon* 10 20 10 10 -
Agroblen (Osmocote) 12 16 8 9 3 
Nutricote* 12 16 10 10 -
Macrocote* 12 16 4 10 -
*With trace or minor elements 
Use of Fertilisers 
In rubber cultivation, any type of fertiliser can be used as long as it contains nutrients 
required by rubber. But its nutrient contents must be adjusted to those of the RRIM 
mixtures. For example, NPK Yellow can be used in place of RRI Mixture Magnesium M, 
but the nutrient contents must first be adjusted accordingly: 
Total nutrient % in RRI Mixture Magnesium M = 30.0
 =
 g 75 
Total nutrient % in NPK Yellow = 40.0 
To determine the quantity of NPK Yellow to be applied can be calculated by 
multiplying the quantity recommended for RRI Mixture Magnesium M by the factor 0.75. 
For example, 168 g of RRI Mixture Magnesium M is recommended for a ten-month old 
rubber, but only 126 g of NPK Yellow (168 x 0.75) is required. Because of the higher 
nutrient contents in compound fertiliser, less quantity is used. This may reduce labour 
in manuring and transport cost of fertilisers. 
In terms of growth, there is not much difference between the mixture and the 
compound fertilisers, as rubber is a perennial crop. This proves that both have the same 
nutritional value. Therefore, fertilisers should be compared more in terms of costs, from 
the time of procurement until it is finally applied. 
149 
Placement of Fertiliser 
For the first round of manuring, 113 g rock phosphate is incorporated into the planting 
hole at the time of planting. For the second and subsequent rounds, fertiliser is broadcast 
evenly around the base of the plant in a full circle, the radius of which depending on its 
age (7ab/e 6.11 and Figures 6.2 to 6.5). 
a) Fertliser is broadcasted around the 
base of the plant 
b) Fertiliser is raked through the ground 
in full circle 
Figure 6.2 Fertiliser application for young trees less than 15 months (circle broadcasting) 
150 
15 months 
Figure 6.3 Diagram showing method of fertiliser application on young rubber 
Figure 6.4 Diagram showing placement of fertiliser on mature rubber trees 
151 
(a) Broadcasting fertiliser along 2 m width strip for immature rubber 
152 
TABLE 6.11: MANURING SCHEDULE FOR IMMATURE RUBBER IN THE FIELD 
Month after planting Amount of fertiliser (g/tree) 
2 150a 
5 150 a 
8 150 a 
11 150 a 
15 300 a 
19 300 a 
23 300 3 
28 450 a 
33 450 a 
39 700 b 
45 700 b 
52 700 b 
60 700 b 
a = Mix. Mag X (8.4 % N, 14.5 % P2 0 5, 7.2 % K20, 2.1 % MgO) 
b = Mix. Mag Y (10.7 % N, 10.4 % P2 Os, 7.2 % Kfi, 2.1 % MgO) (Alternative fertiliser is NPK Yellow) 
Schedule of Manuring 
Manuring young rubber on inland soils. For inland soils, the schedule of manuring 
for young rubber is a general one. The types of fertiliser are dependent on the age 
of plants and the soil type. Low-potassium soils are usually the sandy soils, while 
medium-potassium soils are usually the loamy soils. In areas where legume cover 
crops are planted, large quantities of nitrogen are returned to the soil, thus no additional 
N fertiliser, such as ammonium sulphate is needed. In the early stages of growth, 
Magnesium X containing soluble phosphate should be applied to both types of soil. 
After that a change is made to RRI Mixture Magnesium M for the medium K soils and 
RRI Mixture Magnesium X for the low K soils for thirty four months. From thirty eight 
months onwards. RRI Mixture Magnesium C2 and RRI Mixture Magnesium Y are used 
for the medium K and low K soils respectively. Manuring of young rubber normally ends 
at sixty-two months, during which time the trees should be ready for tapping (Table 
6.12). 
153 
TABLE 6.12 GENERAL MANURING SCHEDULE FOR YOUNG 
RUBBER ON INLAND SOILS 
Time of 
application 
(month after 
planting) 
Type of fertiliser Quantity per plant (g) 
Medium K soils Low K soils 
Areas with 
legume 
covers 
Areas 
without 
legume 
covers 
1 RRI Mixture Mag X* RRI Mixture Mag X* 57 57 
2.5 RRI Mixture Mag X* RRI Mixture Mag X* 85 85 
4 RRI Mixture Mag X* RRI Mixture Mag X* 85 85 
5.5 RRI Mixture Mag X* RRI Mixture Mag X* 113 113 
7 RRI Mixture Mag X* RRI Mixture Mag X* 113 113 
9 RRI Mixture Mag X* RRI Mixture Mag X* 113 113 
11 RRI Mixture Mag X* RRI Mixture Mag X* 170 170 
12 Ammonium sulphate Ammonium sulphate - 113 
13 RRI Mixture Mag M RRI Mixture Mag X 170 170 
14 Ammonium sulphate Ammonium sulphate - 113 
15 RRI Mixture Mag M RRI Mixture Mag X 170 170 
16 Ammonium sulphate Ammonium sulphate - 113 
18 RRI Mixture Mag M RRI Mixture Mag X 170 170 
19 Ammonium sulphate Ammonium sulphate - 170 
21 RRI Mixture Mag M RRI Mixture Mag X 227 227 
22 Ammonium sulphate Ammonium sulphate - 227 
24 RRI Mixture Mag M RRI Mixture Mag X 227 227 
25 Ammonium sulphate Ammonium sulphate - 227 
27 RRI Mixture Mag M RRI Mixture Mag X 284 284 
28 Ammonium sulphate Ammonium sulphate - 227 
30 RRI Mixture Mag M RRI Mixture Mag X 340 340 
31 Ammonium sulphate Ammonium sulphate - 284 
34 RRI Mixture Mag M RRI Mixture Mag X 340 340 
36 Ammonium sulphate Ammonium sulphate - 340 
38 RRI Mixture Mag C2 RRI Mixture Mag Y 340 340 
40 Ammonium sulphate Ammonium sulphate - 340 
42 RRI Mixture Mag C2 RRI Mixture Mag Y 454 454 
44 Ammonium sulphate Ammonium sulphate - 340 
46 RRI Mixture Mag C2 RRI Mixture Mag Y 454 454 
48 Ammonium sulphate Ammonium sulphate - 454 
50 RRI Mixture Mag C2 RRI Mixture Mag Y 454 454 
53 Ammonium sulphate Ammonium sulphate - 454 
56 RRI Mixture Mag C2 RRI Mixture Mag Y 454 454 
59 Ammonium sulphate Ammonium sulphate - 454 
62 RRI Mixture Mag C2 RRI Mixture Mag Y 454 454 
65 Ammonium sulphate Ammonium sulphate - 454 
'Use equivalent RRI Mixture Magnesium X that contains soluble phosphate 
Mag = Magnesium 
154 
During the sixty-two months period, a total of twenty one rounds of fertiliser 
application is scheduled. This may give rise to difficulties in remote areas, hilly terrain 
and those facing logistic labour problems. Table 6.13 gives an interim manuring 
schedule for young rubber on inland soils, in which the number of rounds have been 
reduced to seven. 
TABLE 6.13 INTERIM GENERAL MANURING SCHEDULE FOR YOUNG 
RUBBER ON INLAND SOILS 
Time of application Type of fertiliser Quantity per tree 
At time of planting* Woodace No 4 or 5 pellets 
Kokei Field King or 7 pellets 
Greenpile** 1 piece 
Months after planting 
12 Woodace No 4 or 10 pellets 
Kokei Field King or 7 pellets 
Greenpile** 2 pieces 
30 RRI Mixture Magnesium X 450 g 
36 RRI Mixture Magnesium Y 650 g 
42 RRI Mixture Magnesium Y 650 g 
48 RRI Mixture Magnesium Y 650 g 
54 RRI Mixture Magnesium Y 650 g 
* To be placed in the planting hole 
" Greenpile A Type 1 
RRI Mixture Magnesium X and Y or their equivalents 
Manuring young rubber on coastal clay soils. As usual 113 g of rock 
phosphate is incorporated in the planting hole at time of transplanting rubber. After that, 
fertiliser is not normally required, except when poor growth of rubber is encountered. In 
such cases, only nitrogenous fertiliser should be given, either ammonium sulphate or 
urea (Table 6.14). 
TABLE 6.14 MANURING SCHEDULE FOR YOUNG RUBBER 
ON COASTAL CLAY SOILS 
Time of application 
(month after planting) 
Type of fertiliser (g per tree) 
Ammonium sulphate or Urea 
2 56 28 
5 84 42 
8 170 85 
Note: After eight months, fertiliser application can be continued if necessary, following the schedule in Table 
6.12 but using ammonium sulphate at half or urea at one quarter rate that of the mixture fertiliser. 
155 
Manuring mature rubber. In principle, fertiliser is given annually right up to 
three years before replanting. The type and rate are dependent on the soil series and 
whether or not the clone is susceptible to wind damage (Table 6.15). 
TABLE 6.15 MANURING SCHEDULE FOR REPLANTED MATURE RUBBER (KG/HA/YEAR) 
Soil series Clones not prone to wind damage 
Clones prone to wind 
damage 
Rengam/Jerangau 400 (RRI Mixture J) 300 (RRI Mixture W1) 
Munchong/Prang 350 (RRI Mixture Y) 250 (RRI Mixture W2) 
Melaka/Gajah Mati/Tavy/Durian 300 (RRI Mixture Y) 200 (RRI Mixture W2) 
Serdang* 400 (RRI Mixture J) 300 (RRI Mixture W1) 
Telemong/Telega/Akob 400 (RRI Mixture Y) 275 (RRI Mixture W2) 
Manik/Sogomana/Sitiawan 350 (RRI Mixture Y) 250 (RRI Mixture W2) 
Klau 400 (RRI Mixture J) 300 (RRI Mixture W1) 
Holyrood/Lunas** 450( RRI Mixture J) 350(RRI Mixture W1) 
Selangor/Briah 50 (Urea + 50 (Potassium 
chloride) 
50 (Urea + 50 (Potassium 
chloride) 
Telok/Kranji/Linau 350 (RRI Mixture J) 280 (RRI Mixture W2) 
'Manuring in February/March and May 
'Manuring in February/March, May and August. 
In the meantime a general manuring schedule for mature replanted rubber can 
be used (Table 6.16). 
TABLE 6.16 GENERAL MANURING SCHEDULE FOR MATURE REPLANTED RUBBER 
(KG/TREE/YEAR) 
Inland soil Coastal clay soil 
RRI Mixture MM1 
1-1.125 
Ammonium sulphate or Urea 
0.25 0.125 
The recommendation in Table 6.16 can be implemented only if the trees, during 
their immaturity period, had received adequate fertilisers, including the rock phosphate 
applied to the legume covers. Otherwise, RRI Mixture Magnesium Y at 1-1.125 kg and 
ammonium sulphate at 230 g per tree should be applied annually. 
As Kuantan series soil is said to contain high quantities of N, P, Mg and Mn, it is 
sufficient to apply only potassium chloride at 0.25-0.5 kg per tree annually. 
The best time to apply fertiliser to mature rubber is during the wintering period, 
that is approximately 100 days after leaf fall, as uptake of nutrient by the plant is most 
active during this period. 
156 
Nutrient Cycle 
Nutrients constantly undergo numerous transformation processes, from the time of land 
clearing and initial establishment of rubber right up to the various stages of development 
of the rubber plantation. Although the individual processes may head in different 
directions, the nutrients generally move through a cycle. Basically, the cycle consists 
of two main phases - the plant phase and the soil phase. The inter-relationships of the 
two form the basis of the ecosystem in the rubber plantation. The transfer of nutrients 
between soil and vegetation, the transformation of nutrients in the soil, losses of nutrients 
from the cycle and gains of nutrients in the soil, losses of nutrients from the cycle and 
gains of nutrients by the cycle are illustrated in Figure 6.6. 
157 
REPLACEMENT AND THINNING OUT 
Among the maintenance work required in rubber cultivation are replacement of failed 
plants and thinning out. Brief descriptions of these two operations are given in the text 
below. 
Replacement 
During the early stages of growth, rubber plants which fail to survive are replaced. As 
the age of the rubber tree increases, all replacement work to be carried out must be 
balanced with thinning out. But when a group of nearby trees die, some have to be 
replaced, if not all. 
When carrying out replacement, trees of the same girth size are used, so that 
they too reach maturity at the same time as the rest, in the same area. This operation 
can easily be implemented if the 10% reserved planting materials were included in the 
original transplanting work. Replacement work should not be carried out at a failure 
point where the crowns of the two adjacent trees have touched each other. 
Thinning Out 
Thinning out is the removal of selected trees from a plantation. In the smallholding 
sector, thinning out work is minimal and limited, too. This is because of the limited 
nature of the smallholding area, where every tree counts. 
Previously, it has been the practice in the estates sector to implement a thinning 
out programme of as high as 20% from the original density. Estates which used clonal 
seedlings as the planting materials, used to thin out as high as 30% of the stand. This 
is due to the variations in characteristics of seedlings materials. Today, this operation is 
still carried out, but on a lower scale. The criteria for thinning out are as follows: 
• Poorly growing trees known as runts 
• Badly deformed trees 
• Diseased trees which are beyond treatment 
• Badly damaged trees which are beyond repair 
• Poor yielding trees (for clonal seedling materials only) 
158 
Thinning out can be done by uprooting, felling or poisoning. Thinning out results in 
more space for the rest of the tree population, and reduces inter-tree competition. It 
also reduces wastes on fertilisers and other tree maintenance work. In a mature stand, 
thinning out results in higher yield per tree and'better bark renewal. 
PRUNING 
A rubber tree does not normally require branches on the stem below a height of 3 
metres. This is because a clean smooth stem is needed to facilitate tapping when 
the tree matures. In the estates sector, this height may differ from estate to estate, 
depending on the exploitation policy of each company. To obtain a smooth clean 
stem, all the side branches are pruned off from time to time. Pruning is the removal of 
any part of the plant by physical cutting. In rubber, it is mostly done to the branches. 
The pruning technique is important so that very little disturbance is caused to the 
tree growth. It can be divided into two categories - corrective and controlled pruning. 
Objectives of Pruning 
The objectives of carrying out corrective pruning are to: 
• correct defective trees resulting from defective branchings 
• stabilise the tree 
• reduce wind damage incidence at a later stage of tree growth 
The objectives of implementing controlled pruning are to: 
• obtain a straight clean stem for tapping 
• retain leaves on the plant for as long as possible 
• enhance growth, thus, reducing immaturity period (Table 6.17) 
• improve yield (Table 6.18) 
TABLE 6.17 EFFECT OF CONTROLLED PRUNING ON GROWTH 
AND TAPPABILITY OF RRIM 600 
Experiment Treatment 
Five years later 
Girth (cm) Tappability (%) 
1 Estate pruning* Controlled pruning 
47.2 
49.6 
36.5 
53.4 
2 Estate pruning * Controlled pruning 
44.9 
46.1 
49.7 
59.1 
•Pruning of all branches as they appear to obtain a 300 cm clean straight stem 
159 
TABLE 6.18 EFFECT OF CONTROLLED PRUNING ON TAPPABILITY AND YIELD 
Treatment Tappability (%) First year average yield 
g/t/t kg/ha 
EP 34.5 35.9 630.8 
IL-4FP 47.3 34.8 812.0(129) 
IL-2WP 46.9 35.9 794.9(126) 
IL-3WP 39.1 32.5 603.3 (96) 
IL-PCP 48.7 38.3 829.8(132) 
IH-2WP 45.8 37.9 791.4(126) 
IH-3WP 53.7 36.4 880.1(140) 
IH-PCP 52.6 40.5 955.2(151) 
*Yield for the first half year tapping was from one replicate and subsequently yield from two replicates, tapping 
system used was 1/2S d/3 
EP = Estate pruning, IL = Induced low, IH = Induced high; 4FP = four flush pruning, 3WP = Three whorl-
branch pruning; 2 WP = Two branch pruning, PCP = Planter's Conference pruning 
Figures within brackets are percentages of treatment EP. 
Corrective Pruning 
For budded planting materials, it is important to ensure that only a single scion shoot 
(sprouting from the budpatch only) grows to form the required tree. Any other shoot that 
appears must be pruned off. From this, a strong straight and healthy stem with a central 
branch (which in fact is part of the stem) known as the leader branch must be allowed 
to develop. Side shoots which may appear from whorl to whorl are normally allowed to 
grow unless they are unsatisfactory and require correction, such as: 
• Heavy side branch 
• Vigorously growing side branch overtaking the leader 
• Multiple branches at the top with active leader 
• Multiple branches at the top with retarded or dead leader 
• V-fork branching at the terminal with retarded or dead leader (Figure 6.6). 
To remedy the above situations, the following steps are recommended: 
• Prune off the heavy side branch flush with the stem 
• Prune to shorten the vigorous side branch at a level lower than the leader 
• Prune the multiple branches at the terminal, except the leader, if it is still active 
• Remove the multiple branches at the terminal, if the leader is dead or retarded, 
leaving one that is likely going to become the leader 
• For V-fork branching with dead or retarded leader, remove one arm of the V-fork 
(Figure 6.6) 
160 
Controlled Pruning 
For controlled pruning, no pruning of side shoots or branches that appear on the first or 
second whorl is carried out. But when the third whorl of branches appears, all branches 
at the lowest whorl are removed. The plant continues to grow, and when there, are 
three whorls of branches on it, all branches at the lowest whorl are removed. Pruning 
trees with less than three whorls of branches can also be carried out if the ages of the 
trees reach seven months and branches at the lowest whorl have four flushes of leaves. 
Branches are induced on plants which have no branches and have attained a height 
of 2 metres. Meanwhile, the tree continues to grow, and the same pruning operation is 
repeated until 3 m of clean straight stem is achieved. This normally takes about eight 
to ten months (Figure 6.7). After that the tree is allowed to continue growing until it 
reaches maturity. 
(c) Too many branches at the top (d) Pruning all branches including the leader, 
with retarded leader leaving one to assume the leader branch 
Figure 6.7 Example of corrective prunings 
161 
(a & b) Pruning not required on plants with one or two whorls of branches 
(c & d) All lower branches need to be pruned leaving the plant with three whorls 
162 
(g & h) Pruning of plants with less than three whorls of branches after seven months, 
provided the lowest branches have four whorls of leaves on them 
163 
(i & j) Inducing branches on plants that do not develop branching after reaching a height of 2 m 
Figure 6.8 Various types of controlled pruning 
Pruning should be done to avoid emergence of unwanted side shoots. It must 
be done by a pair of sharp scateurs, pruning saw or rollcut to obtain a clean cut. All 
surfaces must be treated with suitable fungicidal wound dressing such as the Shell Tree 
Dressing (Figure 6.8). 
(a) Pruning a branch using a pruning saw (b) Applying wound dressing to the cut surface 
Figure 6.9 Pruning technique 
164 
It can be noted from Table 6.24 that the last treatment IH-PCP gives the best 
response in terms of yield (151% over control) and, to a certain extent, the tappability 
rate of 52.6%. But the pruning technique involved is too complex and is not very 
practical. The next best result comes from treatment IH-3WP which gives the highest 
tappability rate of 53.7% and the yield of 140% of control EP. This is the three-whorl 
branch pruning currently recommended. 
Controlled pruning can also be termed as delayed pruning. By delaying 
pruning of the side branches, leaves are retained for a much longer period on the 
tree, thus more efficient photosynthesis takes place. This in turn, enhances growth 
and later, the yield. 
BRANCH INDUCTION 
It has been established that leaves play an important part in the growth of plants, 
including rubber. This is because, the chlorophylll in the leaves is the medium for 
photosynthesis. The large number of leaves present on the plant results in large leaf 
area for more efficient trapping of sunlight and thus enhances photosynthesis. Leaves 
are found on branches. Therefore, the emergence of more and early branches result 
in the early emergence of large number of leaves on the plant. Early branching can 
be induced. 
Objectives of Branch Induction 
The main objectives of inducing early branching on the rubber tree, are to: 
• obtain large number of leaves at an early stage of growth 
• obtain large total leaf surface area for better trapping of sunlight 
• stimulate more efficient manufacture of plant food 
• enhance growth of rubber (Table 6.25 and Figure 6.9) 
• reduce the unproductive period of the rubber tree 
o reduce the overall tree height (Table 6.26 and Figure 6.10) 
165 
TABLE 6.19 EFFECT OF BRANCH INDUCTION ON GROWTH OF 
FOURTEEN MONTHS OLD TREES 
Treatment 
After induction (cm) 
0 month 6 months 9 months 12 months 
Without induction 9.4 13.9 16.1 18.1 
With induction 9.1 13.7 16.6 19.1 
Difference - +0.1 +0.8 +1.3 
TABLE 6.20 EFFECT OF BRANCH INDUCTION ON TREE HEIGHT OF FOURTEEN 
MONTHS OLD TREES 
Treatment 
Height after induction (m) 
0 month 12 months 
Without induction 4.5 7.4 
With induction 4.5 6.6 
Difference - 0.8 
a) Non-branching plant growing
 b ) induced-branching plants are shorter, stable and girth well 
tall and becoming unstable 
Figure 6.10 Effect of branching on the rubber tree 
166 
Method of Branch Induction 
Branch induction is normally carried out on trees with late branching habit such as 
RRIM 600. It is also done on other trees that do not branch on reaching a height of 2 
metres. The technique involves the covering of the terminal shoots by leaf capping or 
folding, depending on the condition of the terminal shoot. Terminal shoot conditions 
are divided into five stages of growth i.e. bud-break less than 2 cm, bud-break more 
than 2 cm, leaflet, pendant and hardened stages. 
For terminals with bud-break less than 2 cm, pendant and hardened stages, the 
top whorl of leaves are folded down to enclose the epical bud. The leaves are tied with 
a rubber band going round twice (Figure 6.10). This technique is called the leaf fold 
method. For terminals with bud-break more than 2 cm and leaflet stages, three pieces 
of matured rubber leaves are taken and folded to form a cap enclosing the epical bud. 
The cap is tied with a rubber band going round twice. This method is known as the leaf 
cap method (Figure 6.10). 
The folding and capping are removed after three to four weeks, during which 
time side shoots have started to appear (Figure 6.10). Success of branch induction can 
reach as high as 80% and as low as 60%. 
(a) Bud-break terminal (b) Pendant terminal 
167 
(c) Hardened terminal (d) Covering the terminals by leaf folding 
(e) Bud-break more than 2 cm terminal (f) Leaflet terminal 
168 
(g & h) Covering them by capping 
(i & j) Induced branchings five weeks later 
Figure 6.11 Inducing branches 
The ideal branching habit for the rubber tree is a strong straight stem extending 
right up to the tip of the tree. In other words, the existence of a main central branch 
known as the leader; the rest are only side branches, relatively smaller in size, well-
arranged along the leader, with wide angles. The leader is important to the rubber tree 
as its function is to balance the crown and to provide stability. 
169 
There are also other methods of inducing branches on to the rubber tree and 
they are listed below: 
• Pollarding the crown 
• Ringbarking the stem 
• Ringcutting the bark 
• Defoliating the leaf completely 
• Leaf trimming with chemical spraying 
In the first method, the tree loses its leader and this is not safe for the tree. 
Furthermore, the branches that emerge to take the place of the leader may not be 
desirable. At the same time, the shock to the tree is great. In the second and third 
methods, the success of inducing branches is low and they mostly produce unhealthy 
flushes. Defoliating the tree completely, which is the fourth method, gives high branching 
success, but will result in a severe shock to the tree. Therefore, it is not recommended. 
Defoliating the tree gives almost 100% success, but the chemicals used (Atrinal and 
Benzyladenine) are expensive. 
The leaf fold and the leaf cap methods described earlier in the chapter are still 
preferred. They are simple, fairly effective and cheap. 
REPAIRS AND GENERAL MAINTENANCE 
Apart from maintaining crops, there are a few other operations which are equally 
important and have to be executed. These can be considered as repair and general 
maintenance work. 
Materials, equipment, amenities, buildings, infrastructure and machinery which 
are damaged or worn out due to long usage need to be repaired when necessary. This 
is an on-going operation covering the whole economic life of the plantation. 
In hilly areas, terraces which are broken or defective must be repaired so that 
they are functional at all times. In the low-lying areas, drains that are silted, blocked 
and grown with weeds must be cleaned, cleared and deepened so that flow of water is 
always efficient. If there are roads on the plantation, they should be regularly graded 
with the side drains cleaned and desilted. Rotted fencing posts must be replaced and 
damaged fencing wires repaired. Besides these, maintenance of buildings, stores, 
factories, field equipment agricultural and factory machinery is equally important. 
170 
In normal management practices, worn out items are usually repaired or replaced 
when necessary. But there are other works that require regular periodic maintenance 
such as machinery and motorised vehicles. It is therefore important for the plantation 
to draw up schedules for executing such works so that they are carried out when the 
time comes. For that purpose, adequate spare parts of such machinery and other 
items must be made available as replacements. All these are part and parcel of good 
plantation management. 
TREE GROWTH CENSUS 
Rubber trees are measured for their girths from time to time to assess their performance 
in terms of growth. This is known as tree girth census or survey. This is considered as 
an important post-planting field operation. 
Objectives of Girth Census 
Like all other plantation activities, implementing tree growth census also has its own 
objectives, which are to: 
• monitor growth of the planted crops 
• make corrections where necessary 
• find out whether other inputs are required by the plants 
• determine the exact time when the trees can be brought into tapping 
• make preparations for tapping. 
Method of Girth Census 
Tree girths are measured from time to time, beginning twelve months from planting. It 
is repeated every six months until the girths reach 35 cm, which is approximately three 
and a half to four and a half years after planting. After that, census is done every three 
months. This is known as tapping census or survey. 
Measurements of girths of a large number of trees in an area give more accurate 
information of their growth status. In fact, if possible all the trees in an area should 
be surveyed. But this can entail a lot of work incurring additional cost. Therefore, 
only a few selected trees are taken to represent the whole tree population of an area. 
The same trees are again measured at subsequent survey rounds. Measurements are 
made in centimetres, taken at 150 cm for buddings and 75 cm for clonal seedlings, from 
ground level. A black band mark is made on the stem of trees measured and they are 
171 
subsequently numbered. This is to ensure that the same trees are measured at the 
height in subsequent surveys rounds. Details regarding the census, especially the girth 
measurements, are entered in a special record book. Below are some suggestions as 
to the selection of samples for tree girth census: 
• Eight to twelve trees per hectare from selected planting rows are surveyed 
• For every 10 ha area, a 0.25 ha block of trees is surveyed 
• Three to five percent of the total number of trees in an area surveyed are taken 
from selected planting rows of at least twenty consecutive trees per row 
• All trees along the diagonals of an area are surveyed 
• For smallholding area below 2 ha, all trees are surveyed. 
Girth measurements of trees approximately below half the average size should 
not be recorded as this can drastically bring down the average girth. A record of runt 
(R) should be entered instead. For the vacant points, an entry of V should be made. 
When completed, a rough plan of the area should be drawn, showing the position of the 
planting rows and the path or route taken in carrying out the census. This is to facilitate 
subsequent survey operations. This work can be made easy if the area already has a 
point plan as recommended in an earlier chapter. 
Benefit of Census Records 
All measurements taken are totalled up, and then divided by the number of trees 
measured. This gives the average girth of the trees measured in the whole area. This 
average should be compared with the previous one taken six months ago to obtain 
feedback on the growth situation of the trees. 
172 
CHAPTER 7 
WEEDS AND THEIR CONTROL 
WEEDS 
Weeds are defined as plants that grow where they are not wanted. They are not planted 
but self-grown. 
Advantages of Weeds 
There are several advantages for the existence of weeds on the rubber plantation, and 
among them are : 
• Weeds help to reduce soil erosion by reducing the direct impact of rainfall on 
the soil surface 
• They keep the soil surface cool by reducing the direct impact of sunlight on the 
soil surface 
• They help to preserve moisture in the soil 
• They add organic matter to the soil from their leaf litter 
• They provide food to animals 
• Certain weed species are used in traditional medicines 
Disadvantages of Weeds 
The disadvantages of weeds outweigh their advantages, and they are as listed below: 
• They compete with rubber for water, nutrients, sunlight, air and space (Table 7.1) 
• Certain weed species inhibit growth of rubber (Table 7.2) 
• They delay maturity of rubber (Table 7.3) 
• They affect yield 
• They increase cost of plantation maintenance 
• They provide sanctuaries for pests of rubber 
• They affect efficient flow of water in drains 
173 
TABLE 7.1 EFFECT OF WEED UNDERGROWTH ON GROWTH OF RUBBER 
Field block Age of rubber (Month) 
Girth of tree with 
undergrowth slashed (cm) 
Girth of tree with 
undergrowth unslashed (cm) 
I 36 34.01 30.40 
42 33.93 32.87 
II 36 30.02 29.03 
42 32.97 30.33 
III 36 37.69 35.53 
42 45.54 42.72 
TABLE 7.2 EFFECT OF WEEDS ON GROWTH OF RUBBER FIVE YEARS AFTER 
PLANTING (GIRTH OF TREE IN CM) 
Types of weed Inland soil Coastal clay soil 
Imperata cylindrica 18 24 
Grasses 36 40 
Legumes 40 41 
TABLE 7.3 EFFECT OF WEEDS ON IMMATURITY PERIOD OF RUBBER 
Types of weed Melaka series soil (month after field budding) 
Seremban series soil 
(month after planting) 
Mikania micrantha 80 63 
Grasses 68 59 
Legumes 61 56 
174 
Prevention of Weed Infestation on Rubber Plantation 
The current cost of weed control on a rubber plantation is very high, amounting to 25% 
of the total immature cost. Therefore, preventing weeds from dominating the plantation 
is very much cheaper. 
When clearing land for plantation development, the felled vegetations are burnt 
and the heat produced scorch the weed seeds in the soil, thus preventing them from 
germinating. The soil can be tilled (ploughed and harrowed or rotovated) so that roots of 
weeds are exposed to sunlight and finally dried. Cleared land must not be left exposed 
for too long. Entry of weed seeds from nearby areas must be prevented. Legume 
creeping cover crops must be established immediately. Before planting the legume 
cover crop seeds, make sure that pre-emergent herbicide is blanket-sprayed to the 
area. 
Method of Weed Control 
Weeds that are already on the plantation must be controlled regularly to keep them 
suppressed all the time. This can reduce their competitive effect on rubber. There 
are two areas where weed control is required - weeds growing in the inter-rows and 
weeds growing along the planting strips or terraces. In practice, the inter-rows are 
established with legume cover crops and weed control is limited to those weeds growing 
within them. This is taken care of by legume purification. Areas that are not planted 
with legume cover crops will certainly be infested with weeds that require minimum 
control. Such weeds should be controlled by slashing so that they are not taller than 60 
centimetres. Total eradication of inter-row weeds is not recommended, especially on hill 
slopes, except perhaps, for the very noxious one such as Imperata cylindrica. Weeds 
growing along the planting rows of two metres width or terraces must be controlled to 
the maximum. This can be done by manual hoeing (cangkul) or chemical herbicide 
spraying. Nowadays, manual hoeing is quite costly and the process is quite slow. 
Moreover, weed regeneration is very fast as the weed stumps left in the soil are able 
to reproduce new shoots within days. This method can also cause damage to rubber 
roots, and is therefore undesirable. Period of control by herbicide spraying is very much 
longer, and in some cases up to three months or more. Rubber roots are not damaged 
and the cost is very much cheaper. 
In the initial stage of rubber growth, weed control can be frequent, but as the 
trees grow older, the frequency becomes less and less. This is due to the shading effect 
of rubber on weed growth (Table 7.4). 
175 
TABLE 7.4 WEED CONTROL ROUNDS BY HERBICIDE SPRAYING 
Year Weeds along planting strips Weeds in the inter-
rows 
1 Four to six Six 
2 Four to six Four 
3 Four Three 
4 Four Two 
5 Four One 
6 Three One 
7 Two One 
8 Two One 
9 One -
Type of Herbicide 
There are various types of post-emergent herbicide available in the Malaysian market. 
Their mode of action is systemic as well as non-systemic. Systemic herbicides are 
either translocative or hormonal in action, while the non-systemic kills by contact. In 
Malaysia, hundreds of weed species are found on the rubber plantation and not all of 
them have similar growth characteristics. There is no single herbicide that can control 
all of them. Some herbicides are only effective on broad-leaved weeds while others 
on grasses and some on woody or shrubby growths. Thus, when mixed weed species 
exist on a plantation, a mixture of herbicides has to be used. Tables 7.5 & 7.6 are for 
treatment of weeds in young rubbr area and mature rubber plantations, respectively 
some noxious weeds are listed in Figure 7.1. 
Attention is to be given when spraying weeds along planting strips or terraces, 
the rate and volume should be reduced by using the following formula: 
. . . . . . . Rate per hectare x width of planting strip 
Volume per strip per hectare = Distance between planting rows 
176 
Example: 
3 litres 
5 metres 
2 metres 
3 x 2 = 1.2 litres 
5 
450 litres 
5 metres 
2 metres 
4 5 0 x 2 = 180 litres 
5 
TABLE 7.5 TYPE OF HERBICIDES FOR YOUNG RUBBER AREA 
Type of weeds Type of herbicides Rate per hectre 
Rate for 18 litre 
(knapsack sprayer) 
Broad and small leaves, 
e.g.: 
Mikania micrantha 
Asystasia gangetica 
2,4-DAmin 
Ally 20DF 
Basta 15 
30 litres 
0.75 kg 
3.3 litres 
120 ml 
3g 
132 ml 
Small grass, e.g.: 
Paspalum conjugatum 
Elicine indica 
Basta 15 
Roundup 
3.3 litres 
3.0 litres 
132 ml 
120 ml 
Mixed grass with broad 
and small leaves 
Roundup 
Basta 15 
Hat-Trick 
Starmix 
Roundup + Ally 20DF 
3.0 litres 
3.3 litres 
4.4 litres 
2.15 litres 
3 litre + 0.15 kg 
120 ml 
132 ml 
176 ml 
86 ml 
120 ml + 6 g 
Noxious Weeds, e.g.: 
Imperata cylindrica 
Penisetum polystachion 
Ischaenum muticum 
Round up 
Touchdown 
6.0 litres 
6.0 litres 
240 ml 
240 ml 
Woody weeds, e.g.: 
Chromolaena odorata 
Melastoma malabathricum 
Clidemia hirta 
Starane 200 
Gadon 250 
Banvel 400 
Tordon 101 
Ally 20DF 
1.0 litres 
1.25 litres 
2.0 litres 
2.0 litres 
0.15 kg 
40 ml 
50 ml 
80 ml 
80 ml 
6 kg 
Ferns, e.g.: 
Dicranopteris linearis 
Stenochlaena pelustris 
Basta 15 
2,4 - D Amine + 
Sodium chlorate 
6.0 litres 
3.0 litre + 20 kg 
240 ml 
120 ml + 800g 
Rate of Roundup per blanket hectare = 
Distance between planting rows = 
Width of planting strip = 
Rate of Roundup per strip hectare = 
Volume of water per blanket hectare = 
Distance between planting rows = 
Width of planting strip = 
Volume of water per strip hectare = 
177 
The rates of herbicide recommended in Tables 7.5 and 7.6 are for controlling 
weeds in unshaded or open areas, as in the case of very young rubber areas. Under 
shaded conditions, such as in mature rubber areas, the rates can be reduced by 25% in 
the same volume of water. 
TABLE 7.6 TYPE OF HERBICIDES FOR MATURE RUBBER AREA 
Type of weeds Type of herbicides 
. 
Rate per hectare 
Rate for 18-litre 
knapsack sprayer 
. ... 
Mixed grass with broad 
and small leaves 
Roundup 
Basta 15 
Hat-Trick 
Starmix 
Roundup + Ally 20DF 
3.0 litres 
3.3 litres 
3.0 litres 
1.5 litres 
1.5 litre + 0.075 kg 
120 ml 
132 ml 
120 ml 
60 ml 
60 ml + 3 g 
Noxious Weeds, e.g.: 
Imperata cylindrica 
Penisetum polystachion 
Ischaenum muticum 
Roundup 
Touchdown 
Assault 100A 
3.0 litres 
3.0 litres 
5.0 litres 
120 ml 
120 ml 
200 ml 
Woody weeds, e.g.: 
Chromolaena odorata 
Melastoma 
malabathricum 
Clidemia hirta 
Garlon 250 
Starane 200 
Banvel 400 
Tordon 101 
Ally 20DF 
2.0 litres 
1.25 litres 
2.0 litres 
2.0 litres 
0.15 kg 
80 ml 
50 ml 
80 ml 
80 ml 
6g 
Ferns, e.g.: 
Dicranopteris linearis 
Stenochlaena pelustris 
Basta 15 
2,4-D Amine + 
Sodium chlorate 
6.0 litres 
3.0 litres + 20 kg 
240 ml 
120 ml + 800 g 
(a) Assystasia gangetica (b) Dicranopteris linearis 
178 
(c) Stenochlaena palustris (d) Chromolaena odorata 
Figure 7.1 Several noxious weed species 
179 
Technique of Spraying 
Spraying of herbicide must be carried out systematically so that its effect on weeds 
is almost total, avoiding at the same time wastage of the spray solution. For blanket 
spraying, the area should first be demarcated into blocks, the width of which is double 
the spray swath of the nozzle, and this is usually four metres. When spraying weeds in 
planting strips or terraces, just walk along the strips, releasing the spray solution at the 
same time. A knapsack sprayer of 18-litre capacity (Figure 7.2) fitted with fanjet nozzle 
248 5/64 (Figure 7.3a) for blanket spraying and floodjet nozzle 148 5/64 (Figure 7.3b) 
for strip spraying is used. The herbicide solution can be prepared in bulk using a 200-
litre drum or in small volume of 18 litres using a kerosene tin of 20-litre capacity. When 
preparing herbicide solution, water must first be ready and measured, and if more than 
one chemical is used, they should be diluted one by one to avoid precipitation. The 
solution should be well stirred and then transferred into the knapsack sprayer through 
a strainer. 
Figure 7.2 Knapsack sprayers of 18 litres capacity - brass (left) and PVC (right) 
180 
c 
(c) Hollow conical jet (d) Solid jet 
Figure 7.3 Various types of nozzle 
Pressure of one kg per square centimetre is given into the sprayer body. This 
can be obtained by pumping it six times. The speed of walking during spraying is two 
km per hour. To obtain a spray swath of two metres, the nozzle is raised 60 cm above 
ground. It is very important to have a uniform spraying pressure all through, by giving a 
pump for every step taken. Contact of herbicide solution with the tree must be avoided 
(Figures 7.4 and 7.5). Continue spraying until the sprayer is empty. Refill the sprayer 
and continue spraying until the area is fully covered. All equipment should be washed 
clean immediately after use. 
To obtain good result, spraying should be carried out in the early hours of the 
morning or late afternoon to avoid evaporation of the spray solution. The period of 
control is two to three months, depending on the shade condition. However, respraying 
is only carried out when the regeneration of weeds has reached 60 percent. 
181 
Figure 7.5 Planting strip after spraying of herbicide 
182 
Precaution in Handling Herbicides 
In the course of handling herbicides, precautions must be taken with regards to safety 
to the planted crops, as well as animals and human beings. The following are some 
guidelines: 
• Keep herbicides in safe place 
• Before using herbicides, read and understand the labels thoroughly 
• Use suitable protective clothing (Figure 7.6) 
• Do not eat, drink or smoke when handling herbicides 
• Avoid inhaling concentrated herbicides 
• Do not mix herbicides near crops, fire or waterways 
• Do not blow or suck by mouth blocked sprayer nozzle; use other tools and 
methods to clear it 
• Do not reuse empty herbicide containers; destroy and bury them 
• Immediately wash body and clothing after handling herbicides 
• Consult a doctor immediately if you feel unwell. 
Figure 7.6 Use suitable protective clothing when spraying 
183 
Chemical weed control is not only costly, but also hazardous to health; and, to 
a certain extent, it pollutes the environment. Therefore, where possible, this operation 
should be kept to the minimum. When only one weed species is present on a plantation, 
use the type of herbicide that is effective on it. Avoid the general herbicide mixture. 
Sometimes, repeated use of a particular herbicide on certain weed species may result 
in the colonisation of tolerant or resistant species. This needs careful observation and 
corrective action must be taken to avoid wastage. Another point to consider is to go for 
very low volume spraying, using the controlled droplet applicator (CDA) or motorised 
spraying for the larger areas. Experiments have proved that there are substantial 
savings in cost. 
During the 1980's, RRIM carried out studies on sheep rearing and grazing on 
rubber plantation and found that sheep can be an important and effective agent for 
biological weed control. There was a saving of 17-30% in weed control cost and at the 
same time girthing of rubber improved by 11 percent. Income from the sale of sheep 
reduced the hardship faced by the farmers during the immaturity period, while during 
the maturity period of rubber it became an added income. 
Establishment and maintenance of pure legume cover crops, and the planting 
design of rubber itself can also reduce weed problems on a plantation. The triangular 
and square-shaped planting designs encourage early closure of the rubber canopy, 
resulting in less transmission of light into the plantation and hence less vigorous growth 
of weeds. All these finally lead to the reduction in the use of chemical herbicides and 
consequently the cost of weed control. 
184 
CHAPTER 8 
TREATMENT OF MALADIES AND INJURIES AND CONTROL OF PESTS 
ROOT DISEASES 
Root diseases are considered as the most serious of all diseases in rubber cultivation, 
because they can kill the tree. They are caused by fungi, which initially infect the 
root surface only. After some time, they penetrate the wood tissue, causing the root 
to rot and eventually kill the tree. Root diseases can spread from tree to tree by 
root contact. They can also be spread by the spores which enter the roots through 
any exposed tissue in the stem or branch resulting from wounds. Root diseases 
originally came from jungle trees and spread to the cultivated crops like rubber, when 
plantations started to develop. Besides rubber, a number of other perennial crops are 
hosts to root diseases, too. 
Types of Root Disease 
Six types of root disease are known to infect rubber, out of which three are the major 
ones. They are white, red and brown root diseases. The names are given according 
to the colour of the causal fungi. 
White root d i sease . The name of the fungus is Rigidoporous lignosus. It 
is white in colour. The rhizomorphs are firmly attached to the root. The rhizomorphs 
are threadlike rounded structures, but become flattened towards the end. After some 
time, the colour changes to reddish-brown. The fruit body is usually found growing 
at the base of diseased-dead tree or decaying stump. The upper surface of the fruit 
body bracket is orange-yellow, while the underside is reddish or brownish in colour 
(Figure 8.1a). This disease is very common in young rubber. It is the most serious of 
the three as it spreads very fast. 
Red root d i sease . The name of the causal fungus is Ganoderma philippi. 
The fungus is in the form of mycelium skin covering the root surface. Soil adheres 
to the root and only after washing away the soil can the red mycelium be visible. As 
usual, the fruit body grows at the base of diseased-dead plants or decaying stumps. 
The upper surface of the bracket is dark red, while the underside ash grey in colour 
(Figure 8.1b). 
185 
Brown root disease. The causal fungus is the species known as Phellinus 
noxius. The nature of the fungus is just like the red root disease; only the colour is 
brown which darkens with age. Soil also sticks to the infected root. The root surface 
becomes rough. When it is split open, brownish zig-zag lines can be seen in the wood 
tissues. When the rot is at an advanced stage, the wood becomes friable, light and dry, 
penetrated with sheets of fungal material, forming a honeycomb structure. The fruit 
body is a hard but smaller bracket with dark brown colour on the upper surface and grey 
on the underside (Figure 8.1c). This disease is not so common and usually infects old 
rubber trees. 
(c) Brown root disease 
Figure 8.1 Major root diseases 
186 
Prevention of Root Diseases 
Treating trees infected by root diseases is very difficult and expensive. Therefore, it is 
important to prevent them. Before an old rubber area is cleared for replanting, all root 
disease sources must be removed and burnt. The sources can be located from vacant 
patches or vacant planting points resulting from dead trees. Clearing methods such as 
uprooting and poisoning of old trees have been found to reduce root disease incidence 
in replantings. Even if the trees are manually felled by cutting, the stumps must be 
poisoned and the cut surfaces painted with creosote. All these will deprive the root 
disease fungi of food sources. Establishing and maintaining pure legume cover crops 
can also reduce root diseases as they cause roots and stumps to rot faster. During 
transplanting of rubber, 226 g of powdered sulphur should be incorporated into the 
planting hole. Sulphur is known to promote the growth of fungi which are antagonistic 
to the root disease fungi. Painting of collar protectant chemicals to the collar region of 
the plant can also prevent root disease infection for two years. As the trees grow, there 
are bound to be damages caused to the tissues from time to time. Such open wounds 
on any part of the tree should not be left untreated. Suitable fungicidal wound dressing 
should be applied immediately. This is because root disease spores can enter the tree 
through such wounds. An isolation trench is dug between the infected and healthy trees 
to prevent spread. 
Method of Treatment 
The infected tree must first be located and identified. This can be done by foliage 
inspection at three-monthly intervals, beginning from six-month old plants. Trees with 
unhealthy and deformed leaves should be suspected as root-diseased. This is confirmed 
by collar inspection. The collar region of the infected plant is exposed by digging 
a cavity around the base of the plant; the depth of opening should be about 5 cm 
for a year old to about 20 cm for a four-year old plant. A sharp flat-ended hardwood is 
used for this purpose to prevent unnecessary damage to the roots. When a diseased 
tree is found, the neighbouring trees in the row must also be collar-inspected, although 
they may have been passed during foliage inspection. They may have been infected 
but have not shown symptoms on the leaves. This procedure is continued along the 
row until a disease-free tree is found. 
On the infected tree, part of the root system is exposed. The size of the exposure 
can be from 30 cm for a one-year old plant to 60 cm for a four-year old one, while the 
depth is 20-45 centimetres. All dead roots are removed including the dead portion of the 
tap root and the debris collected and burnt. Any soil found attached to the roots must 
be removed. When the root surfaces have dried, suitable collar protectant is painted 
187 
over the exposed tap root and 15 cm of the lateral roots (Figure 8.2). For white root 
disease use Shell Collar Protectant, while for red and brown root diseases use Calixin 
Collar Protectant. The hole is then refilled by digging the soil from the sides. This is to 
ensure that no diseased roots are left behind to cause reinfection later on. The treated 
tree is marked with the name of the disease and the date of treatment. Trees that are 
collar-inspected and found to be uninfected should also be painted with the protectant. 
The treated tree is reinspected after two years. 
Figure 8.2 Applying collar protectant to diseased roots 
Treatment of White Root Disease by Chemical Drenching 
Plants infected by white root disease in their initial stages can be treated by drenching 
the collar region with fungicides such as Bayleton 25WP (10 g +1 litre water). Procedure 
of locating the trees and identifying the disease is the same as described earlier. The 
collar region of the infected tree is exposed, the size of the cavity being 20 cm wide and 
5 cm deep (Figure 8.3). One litre of the diluted fungicide is poured into it. The cavity 
is then refilled with soil. It must be emphasized that this method of treatment is only 
effective where the infection is at the initial stage, that is, before the fungus penetrates 
into the wood tissues of the root. 
188 
(a) Opening up the collar (b) Pouring in the fungicide 
Figure 8.3 Treating white root diseased-tree by chemical drenching 
Control of Root Diseases in Mature Rubber Area 
The aim of controlling root diseases described earlier is to remove their sources when 
the trees are still young, so that the remaining trees will not be infected with the disease 
when they mature. However, infection can occur from other sources. Therefore, 
preparations must be made towards their control. The principle of root disease control in 
mature rubber is the same as for immature rubber. Tappers normally know the locations 
of the diseased trees and this simplifies work of locating them. Treatment of diseased 
tree is aimed at preventing the spread of the disease. But, as the trees grow older, the 
cost of treatment also increases and the time will come when the infected trees are left 
to their fate and isolated by trenches, so that the diseases do not spread to other trees. 
Details of the isolation trench are given in the following paragraph. 
Isolation Trench 
A trench of 30 cm wide and 60 cm deep is dug all round the infected tree at half the 
distances of the neighbouring healthy trees. All roots found crossing the trench are 
pruned off and the debris collected and burnt. The trench is then refilled with loose soil 
to two-thirds its depth. The trench is reopened yearly and any roots found crossing the 
trench are pruned off and the debris collected and burnt. This procedure is repeated 
several times until the fungus on the infected tree becomes inactive, thus depleting food 
source to the root disease fungus. This will only take place when the infected tree rots. 
Proper siting of the isolation trench is very important, as it is essential to ensure that 
there are no diseased trees outside the isolated area. The procedure is to inspect the 
189 
collars of trees around the infected one until a healthy tree is found and to site the trench 
between the healthy and the diseased trees. When constructing an isolation trench, all 
roots found must be carefully inspected. If diseased roots are found, the position of the 
trench may have to be shifted much further (Figures 8.4 and 8.5). 
Figure 8.4 Cross-section of isolation trench 
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Figure 8.5 Plan of root disease patch isolation 
190 
Other Root Diseases 
Besides the three major root diseases described earlier, there are three other minor 
ones which infect the rubber trees. They are Ustulina root rot, Poria root rot and stinking 
root rot (Figure 8.6). 
(c) Stinking root rot 
Figure 8.6 Minor root diseases 
Ustulina root rot, which is caused by Ustulina deusta can be controlled by pruning 
off any part of the roots that are penetrated by the fungus and the resultant wounds 
treated with suitable fungicidal wound dressing. For Poria root rot, caused by Porta 
hypobrunnea, the rotted roots are also pruned off and the resultant wounds treated with 
the same dressing. If the infected roots are still alive, the disease can be controlled 
by just scraping off the fungus. For stinking root rot, which is caused by Sphaerostilbe 
repens, the infected plants are removed together with the root system and burnt. At 
the same time, the drainage system in the area must be improved. 
STEM DISEASES 
The rubber tree stem, which includes branch, fork and tapping panel, is also subject 
to disease infection. Pathogenic dieback, pink disease, mistletoe, Ustulina stem rot, 
Phellinus stem rot, bark necrosis, mouldy rot, black stripe, panel necrosis and brown 
bast are some of the serious ones. Their causes, symptoms and treatments are briefly 
described below. 
192 
Pathogenic Dieback 
This disease which is caused by the fungus Colletotrichum gloeosporioides infects 
leaves and stems of young scion shoot terminals. The terminal leaves turn brown and 
fall. The stem dies up to the budpatch (Figure 8.7a). Such plants are removed and 
replaced. Stems of plants that suffer partial dieback, should be pruned off up to healthy 
tissues and the resultant wounds treated with suitable fungicidal wound dressing 
mentioned earlier. 
(a) Phatogenic die-back 
Figure 8.7 Types of Stem Disease 
193 
Pink Disease 
Pink disease infects the branch and the fork of rubber tree of three to eight years old. 
It spreads during wet weather. The causal fungus is Corticium salmonicolor and the 
spores are spread by air current. Clones RRIM 600, RRIM 701, RRIM 729, RRIM 901, 
RRIM 905, PB 255 and PB 28/59 are found to be susceptible to this disease. Its early 
symptom is the appearance of a cobweb-like film of silky white mycelium on the branch, 
usually near the fork. Later, drops of latex start exuding from it. As the mycelium 
penetrates the cortical tissues, it becomes more distinct and turns pink in colour. The 
disease spreads around the branch extending up to a metre and can also cross over 
the adjacent branch through the fork. More bleeding occurs which later result in open 
wounds of the bark. The branch dries up with black streaks of coagulated latex on 
it. Several side shoots from dormant buds appear just below it (Figure 8.7b). Pink 
disease can be controlled by fungicide known as Bordeaux mixture which is made up 
of (1 kg copper sulphate + 25 litres water) and (2 kg dehydrated lime + 75 litres water). 
The fungicide can be sprayed on to the infected branch. It can also be brushed on with 
the water content in the formulation reduced to 25%. The copper content in the mixture 
may affect latex properties. Therefore, for mature trees, Calixin should be applied neat 
by brushing or Daconil F500 at 3 litres in 97 litres water by spraying. 
(b) Pink disease 
Figure 8.7 Types of Stem Disease 
194 
Mistletoes 
Mistletoes are semi-parasitic plants growing on other plants such as rubber. They have 
their own leaves and are therefore able to prepare carbohydrates themselves, and are 
not fully dependent on their hosts for food. Two species are commonly found in Malaysia, 
namely Loranthus globasus (Figure 8.7c) and Loranthus pentandrus. Mistletoes are 
connected to the host plant by suckers that penetrate deep into the wood. The affected 
shoot beyond where the mistletoe is attached gradually becomes weak, leafless and 
dies. The infected host branch is pruned off and the resultant wound is treated with 
suitable wound dressing. This operation is best carried out during the wintering season, 
when the mistletoe is easily seen. 
(c) Mistletoe 
Figure 8 7 Types of Stem Disease 
195 
Ustulina Stem Rot 
This disease can infect any part of the stem that has open wounds, cracks in the fork, 
broken ends of large branches and even wounds caused by deeply inserted spouts and 
latex cup hangers, through which the fungus can enter. The causal fungus is Ustulina 
deusta. The early symptoms can be bleeding of latex from any part of the stem or large 
branch, followed by its coagulation resulting in foul-smelling pad beneath the rotted 
bark. Fructifications soon develop on the stem as velvety, greyish-white, flat plates. 
They later turn grey-black or charcoal or grow into a contiguous sheet covering a large 
portion of the wound. This is often followed by borer beetle invasion. The fungus can 
penetrate deep across, causing the stem to snap off {Figure 8.7d). The diseased tissue 
is completely pruned off to a healthy portion and fungicidal wound dressing is applied 
over it. This disease can be easily prevented. Any physical damage to the tree must be 
attended to immediately. Latex spout should not be fixed too deep so that it does not 
touch the wood. Only cup hangers with springs should be used. 
(d) Ustulina stem rot 
Figure 8.7 Types of Stem Disease 
196 
Phellinus Stem Rot 
Phellinus stem rot attacks mature rubber, the causal fungus being Phillinux noxius. 
It infects exposed cut surfaces of stumps, broken ends or branches and any other 
exposed tissue of damaged trees. The rot finally goes down to the roots causing brown 
root disease. The rotted wood is dry and penetrated with plates of brown mycelium 
which gives it the honeycomb-like appearance as in the case of brown root disease 
described earlier (Figure 8.7e). The diseased part should be pruned off to a healthy 
tissue and the wound treated with creosote. This disease can be prevented by giving 
immediate attention to any wounds occurring on the tree either by accidental damage 
or scheduled pruning. 
(e) Phellinus stem rot 
Figure 8.7 Types of Stem Disease 
197 
Bark Necrosis 
This disease infects the bark of the rubber tree, and clones PB 28/59, PB 28/83, PB 
5/51, GT 1, PR 107 and RRIM 605 are found to be susceptible to it. The causal fungus 
has not yet been identified. It spreads during wet season. The lower part of the stem 
below the tapping cut is infected the most. The disease starts as brownish necrotic spots 
on the tapping cut, which may extend to the renewed bark in patches. The disease may 
also start from the top, from cracks in the stem above the tapping panel. In fact, it can 
start from any part of the tree, from the fork right down to the collar (Figure 8. If). When 
the outer bark is scraped off, the disease is seen spreading into the cortex as purplish-
red or reddish-brown patch of moist tissue. During dry weather, the dead cortex drops 
off, the bark regenerates and the tree recovers. But if the wet season is prolonged, the 
cambium is affected, resulting in excessive bleeding of latex with large wounds. Borer 
beetles may attack and the tree eventually dies. The infected area on the tree is treated 
by weekly spraying or brushing with fungicide such as Difolatan at 2%. The infected 
tree should not be tapped for six months. 
r • • • • • • • • H M H i 
(f) Bark necrosis 
Figure 8.7 Types of Stem Disease 
198 
Mouldy Rot 
Mouldy rot infects the tapping panel. The causal fungus is known as Ceratocystis 
fimbriata. The susceptible clones are RRIM 600, RRIM 605, RRIM 501 and PR 107. 
The symptoms are depressed discoloured spots just above the tapping cut which later 
darken and become covered with greyish mould. As the infection spreads, an irregular 
band of infection is formed running parallel to the tapping cut. If not treated, patches 
of exposed areas can develop resulting in large tapping wounds (Figure 8.7g). Spores 
of the fungus are mostly spread by the tapping knives. The disease can be treated by 
fungicides such as Benlate at 0.5% or Difolatan at 2%. The fungicide is sprayed or 
brushed on to the infected panel at weekly intervals. The disease can be prevented by 
having free circulation of air in the plantation. Height of weeds should always be kept 
lower than 60 cm and the tapping knives should be regularly disinfected, especially 
during wet weather. 
(g) Mouldy Rot 
Figure 8.7 Types of Stem Disease 
199 
Black Stripe 
Black stripe is also a disease of the tapping panel. It is caused by the fungus Phytophthora 
palmivora. The disease can spread from tree to tree through the tapping knife. Clones 
AVROS 2037, RRIM 600, RRIM 605, RRIM 607 and RRIM 623 are susceptible to it. 
The symptoms are a series of sunken and discoloured areas just above the tapping 
cut, and later, vertical dark fissures are seen at the same place. The stripe widens and 
coalesces into a broad lesion which may cover the full length of the panel. When the 
bark is scraped, the underlying tissues become discoloured brown or black and narrow 
vertical lines on the surface of the wood (Figure 8.7h). The panel can be treated by 
spraying or brushing with fungicide, such as Difolatan at 2% or Ridomil 25WP at 0.8% 
three times per week. There are also other effective chemicals, such as Sandofan M, 
Fruvit and Caltan. The tapping knife must also be disinfected in the fungicide. The 
infected trees should not be tapped until the rainy season is over. 
h 
(h) Black stripe 
Figure 8.7 Types of Stem Disease 
200 
Panel Necrosis 
This disease, caused by Fusarium solani, infects newly opened tapping panel. It spreads 
during wet weather. The susceptible clones are PB 5/51, PB 28/59, PB 28/83, PR 107, 
RRIM 605, RRIM 612, RRIM 623 and RRIM 628. The disease infects the tapping and 
the panel boundary cuts. Slightly sunken lesions sometimes coalescing into a long 
chain, develop on the bark in the intermediate region of the panel guide markings. If the 
cambium and xylem are infected, the bark decays and splits open (Figure 8.7i). The 
infected tree can be treated by spraying or brushing with fungicide such as Difolatan at 
2% each time after tapping for four to five days. Avoid opening of new tapping panel 
during wet weather. 
(i) Panel necrosis. 
Figure 8.7 Types of Stem Disease 
201 
Brown Bast 
Brown bast (or tree dryness) is not yet considered a disease as it is not connected 
with any pathogen. It is a physiological disorder of the latex vessels in that no latex 
is produced when the bark is tapped away. Almost all clonal seedling materials and 
some of the high-yielding clones are susceptible to brown bast. Symptoms of trees that 
suffer from brown bast can be several, beginning from partial dryness of the tapping cut 
to total dryness of the tree, the most chronic of all being the flaking of the bark (Figure 
8.7}). There is no known cure for brown bast yet. The most effective method currently 
available is to stop it from spreading along the latex vessels, by creating a discontinuity 
between the dry and the yielding areas of the bark. Details of this isolation technique 
are described below. 
(j) Brown bast or tree dryness. 
Figure 8.7 Types of Stem Disease 
202 
Isolation of pre-tapping panel. Brown bast can be prevented by making pre-tapping 
isolation grooves, especially on clones susceptible to it. This is done three months 
before the commencement of tapping. A tapping panel must first be marked out on 
the tree to determine the position of the back and front panel boundary lines. Using a 
specially modified discarded tapping knife, a vertical cut to the wood is made along the 
back panel boundary channel and along the budding union or just above ground level 
(for a deep-planted tree) in the shape of a reversed letter L. This results in the physical 
discontinuity in latex vessels between the two lower panels. This is to ensure that if 
dryness develops on panel BO-1, it will be confined to this panel, without spreading to 
panel BO-2. 
Trees with partial dryness of the tapping cuts. The length of the tapping cut that 
is dry is marked. A vertical groove up to tapping depth is made extending below the 
tapping cut. The groove is continued until the yielding bark. Similar additional vertical 
grooves (1, 2, and 3) are made at 2 cm intervals to the right of the first vertical groove 
(Figure 8.8a). This is repeated till yielding bark is encountered as indicated by the 
presence of latex in test grooves 4 and 5. From this it is clear that dryness is only 
confined to the area ABCD (Figure 8.8a). A deep cut to the wood is made along ABCD 
to isolate it. Tapping is resumed along BC. 
Total dryness on panel BO-1. The whole tapping cut is dry. Two vertical cuts of tapping 
depth 1 and 2 are made downward to determine ten extent of dryness (Figure 8.8b). If 
it is proved from test cut 2 that dryness has spread beyond the left or panel BO-1 and 
into panel BO-2, test cuts 3, 4 and 5 are made upward from the union to determine the 
spread. A sixth test cut is then made on the right of BO-1, and if this shows that there is 
no dryness there, a horizontal cut 7 along the budding union below panel BO-2 is then 
made to prevent the upward spread of dryness form the roots. Tapping can resume by 
opening panel BO-2. 
Total dryness on panel BO-2. If there is complete dryness on panel BO-2, it is usually 
confined to that panel only. Vertical test cuts 1, 2 and 3 are made to find out the 
extent of dryness (Figure 8.8c). If it is proved that dryness has spread into the roots, a 
horizontal cut 4 is made to prevent the upward spread of dryness into panel BI-1 from 
the roots (Figure 8.8c). Tapping can resume on panel BI-1 if the renewed bark is thick 
enough for retapping; otherwise resume tapping on virgin bark above it. 
Total dryness on both the lower panels. For trees with total dryness on both the 
lower panels (BO-1 and BI-2), the virgin bark above them can be exploited by upward 
tapping. 
203 
Re-exploitation of dry bark. If the isolated dry bark is to be retapped later on, it must 
be removed by scraping. The depth of scraping is to remove the brownish discoloured 
bark to maximum of tapping depth. This is to allow new bark to regenerate with fresh 
latex vessels formed. The regenerated bark can be retapped when it is sufficiently 
thick. 
(a) Partial dryness on panel BO-1 (b) Total dryness on panel BO-1 (c) Total dryness on Panel BO-2 
Figure 8.8 Controlling brown bast or tree dryness 
LEAF DISEASES 
Rubber plants suffer from several leaf diseases which affect the well being of the plants. 
The most common leaf diseases in the nursery are Bird's Eye Spot and Colletotrichum 
leaf disease while on mature rubber, secondary leaf fall caused by Oidium heveae 
and Colletotrichum gloeosporioides are the most important leaf diseases followed by 
Phytophthora abnormal leaf fall, Corynespora Leaf Fall and Fusicoccum Leaf Blight. 
Their brief descriptions are given below. 
Oidium Secondary Leaf Fall 
This disease is also known as powdery mildew and caused by the fungus Oidium heveae. 
It infects mostly young shoots that refoliate after wintering. The presence of numerous 
leaflets on the ground is the sign of an attack. Unfolding leaflets of up to 5 cm in length 
204 
are shrivelled and progressively blackened from the leaf tip and fall, leaving the petioles 
attached to the branch for a while (Figure 8.9a). If the tree is shaken, a shower of leaflets 
will fall. Clones PB 217, PB 235, PB 255, PB 260, PB 28/59, PB 280, PR 255, PR 261, 
RRIM 701, RRIM 728, RRIM 901 and RRIM 905 are susceptible to this disease. 
a) Oidium or powdery mildew 
Figure 8.9 Type of Leaf Diseases 
This disease can be controlled by dusting the leaves with sulphur throughout the 
refoliating season at five to six weekly rounds. Fogging with fungicide tridemorph 
such as Calixin 75 EC at 0.5 a.i/ha also provides a good control of the disease. It is 
recommended to avoid planting of susceptible clones in areas prone to the disease. 
Colletotrichum Secondary Leaf Fall 
This disease is caused by fungus known as Colletotrichum gloeosporioides. Leaves 
are most susceptible during the period of budburst and for about ten days thereafter. In 
older leaves, the leaf margins, particularly the tips, are shrivelled, but they are covered 
205 
with small spots with narrow brown margins surrounded by yellow halos a millimetre or 
more in width. As the leaves become older, the spots become slightly raised (Figure 
8.9b). This disease may also cause dieback of green shoots. Susceptible clones are 
PB 28/59, PB 235, PB 255, PM 10, BPM 24, RRIM 712, RRIM 728, RRIM 937, RRIM 
2005 and RRIM 2026. 
b) Collectotrichum disease 
Figure 8.9 Type of Leaf Diseases 
Satisfactory control of this disease in the nurseries or shorter immature planting can 
be achieved using fungicide chlorothalonil and propineb such as Daconil and Antracol 
respectively at 0.2% in water using a knapsack sprayer or a back-pack power mist 
blower. Chemical treatment for mature rubber is not economical, except for very severe 
outbreak. It is recommended to avoid planting of susceptible clones in areas prone to 
the disease. 
206 
Phytophthora Abnormal Leaf Fall 
This disease is caused by the fungus known as Phytophthora botryosa and P. 
palmivora. However, the fungus, Phytophthora botryosa is more commonly observed 
from the Phytophthora leaf fall areas. The infected leaves are often shed with their 
three leaflets attached to the petiole where one or more black lesions with white spots 
of coagulated latex in the middle can be observed. Infected pods become blackened, 
malformed and unopened, but remain on the tree with the seeds inside shrivelled and 
rotten (Figure 8.9c). Infection on terminal twigs usually leads to dieback of green shoots. 
The susceptible clones are RRIM 600, PB 217, RRIM 623, RRIM 905, RRIM 936, PB 
255, PB 28/59 and PM 10. 
c) Phytophthora leaf fall 
Figure 8.9 Type of Leaf Diseases 
This disease can be controlled by spraying with fungicide copper oxychloride in 
oil (1.2 kg a.i/ha) using a mist blower about four weeks before the onset of rainy season. 
Avoid planting susceptible clones in areas prone to the disease is recommended. 
207 
Corynespora Leaf Disease 
The disease is caused by a fungus known as Corynespora cassiicola. It infects both 
young and old leaves, particularly along the veins. Initially, it appears as a greyish dark 
spots which enlarges into circular or irregular papery lesions, surrounded with yellow 
halo ranging from 1 -8 mm in diameter and dark grey in colour. The veins are discoloured, 
giving the characteristic fish-bone appearance. The leaves turn yellow and later drop 
(Figure 8.9d). One lesion is enough to cause defoliation, especially, if it is sited on the 
main vein. Clone RRIM 600 is severely infected by the disease. 
d) Corynespora Leaf Disease 
Figure 8.9 Type of Leaf Diseases 
Satisfactory control of Corynespora leaf disease can be obtained by spraying 
with fungicide benomyl such as Benlate at 0.3%. 
208 
Bird's Eye Spot 
This disease is caused by the fungus known as Bipolaris heveae. This fungus mainly 
attacks poorly growing nursery seedlings. The infection causes refoliation and retards 
the plant growth. Infection on older leaves causes only small dark specks while on 
leaves at fully-green stage, yellow halos are observed around the shot holes (Figure 
8.9e). Younger leaves shrivel before falling off. It can be controlled by weekly spraying 
of fungicides propineb and mancozeb such as Antracol and Dithane M-45 respectively 
at 0.2%. At the same time the seedlings must be given adequate manuring. 
I m m 
e) Bird's eye spot leaf disease 
Figure 8.9 Type of Leaf Diseases 
209 
Fusicoccum Leaf Blight 
Fusicoccum leaf blight, which is caused by a fungus of the Fusicoccum sp., was first 
reported in 1987. Among the susceptible clones are RRIM 600, RRIM 2023, RRIM 2024 
and RRIM 2025. The symptoms are most prominent on expanded leaves. The lesions 
resemble those of anthracnose described earlier but they are larger with concentric 
brownish zones which stand out against the uninfected area. Initial infections appear as 
rusty-brown pin-head size spots which later become large. Lesions are most common 
at leaf tips and margins. Within lesions numerous dark pustules barely recognizable to 
the naked eyes, are found and are abundant on the upper leaf surface. Infected leaves 
gradually turn bronze in colour before abscission (Figure 8.9f). Laboratory evaluation 
showed that fungicides propiconazole, carbendazim, prochloraz and penconazole are 
effective against the fungus. 
f) Fusicoccum Leaf Blight 
Figure 8.9 Type of Leaf Diseases 
210 
PHYSICAL INJURIES 
Rubber trees also suffer from injuries. There are several among them that need attention. 
The following describe briefly the important injuries and their treatments. 
Flooding and Water-logging 
Excess water in the soil surrounding the planted crops can cause breathing difficulties 
to their roots. This can retard growth. The leaves turn yellow-green or total yellow. The 
lenticels of smaller plants become swollen (Figure 8.10a). Prolonged flooding can kill 
smaller plants, while on older trees, it can cause the bark to crack and ooze out latex, 
which later turns to pads of coagulum beneath it. This is usually followed by borer 
beetles attack which finally kills the tree. The roots may later be infected by stinking root 
rot (Sphaerostilbe repens). Its remedy is to remove excess water from the affected area 
by contructing efficient drainage system. 
(a) Flooding and water-logging 
Figure 8.10 Type of Physical Injuries 
211 
Drought 
Plants need water for their general growth. Due to the nature of their structure, sandy soils 
are unable to retain water, thus causing stress to planted crops during drought. Drought 
causes the leaves of young plants to wilt, shrivel and finally die. The green stems are 
also affected and this is followed by dieback. Prolonged drought can also affect older 
plants (Figure 8.10b). Newly wilted plants can recover if watered immediately. Stems of 
plants that have suffered dieback are pruned off to healthy tissues. Field transplanting 
should be avoided during dry season. 
(b) Drought 
Figure 8.10 Type of Physical Injuries 
212 
Sunscorch 
Although plants generally need sunlight for their growth, excessive heat from it can 
cause radiation. As a result the leaves are bleached, severely wrinkled and die. Stems 
of young plants are also affected, in which the bark around the base gets killed. This 
usually happens on sandy soil and where there is no ground cover crops (Figure 8.10c). 
The renewing bark on the tapping panel can get scorched too by direct intense sunlight. 
Newly transplanted materials must be mulched. When transplanting advance-aged 
planting materials, the stems should be lime-washed to enable them to reflect sunlight. 
Plants already affected by sunscorch should be removed and replaced. 
(c) Sunscorch 
Figure 8.10 Type of Physical Injuries 
213 
Fire Damage 
Damage by fire is quite a common incident in rubber cultivation, especially during 
the wintering season, as the condition is dry and there are a lot of dry leaves on the 
ground. The cause of the fire is mostly accidental. Young plants can be killed outright. 
Leaves of older trees become scorched, turn brown and eventually fall. The affected 
bark bleeds, and later is invaded by borer beetles which eventually kill the tree (Figure 
8.10d). Trees affected by fire damage must be immediately (before the borer beetles 
come in) white-washed with a mixture of 500 g dehydrated lime in 1 litre of water and 
2 ml insecticide such as Mitac 20. This is to reduce the radiation effect of sunlight on 
the already scorched bark and at the same time keeps away the borer beetles. Later, 
the affected dead tissues are removed and the resultant wounds treated with suitable 
wound dressing. 
(d) Fire damage 
Figure 8.10 Common physical injuries 
214 
Lightning Strike 
Direct lightning strike can kill the tree instantly, but less severe ones only cause wounds. 
Lightning usually strikes a group of about half a dozen trees, and on one side of the 
trees only. If the strike is on the upper part of the tree, green leaves will fall with the 
petioles attached to the plants. The bark splits and latex oozes out. The bark dies from 
the cambium outwards and finally peels off (Figure 8.10e). Treatment is the same as 
for trees damaged by fire. 
(e) Lightning 
Figure 8.10 Common physical injuries 
215 
Poisoning 
Poisoning of trees usually happens during herbicide spraying, when the spray drifts 
come into contact with the planted crops such as rubber. Large patches of whitened 
dead tissues are seen on the leaves which are later invaded by saprophytic fungi, and 
finally drop. The bark is killed in irregular patches, followed by exudation of latex and 
invasion by borer beetles. Damage can also be caused by uptake of herbicides spilt 
on the ground by the roots (Figure 8.10f). Damages by hormone type of herbicides 
are general in nature, from dieback of the terminal to the roots. All dead tissues are 
removed and the resultant wounds treated with suitable wound dressing. Preparation of 
herbicide mixtures should not be done near the planted crops. Spray drifts should not 
be allowed to get into contact with planted crops. Sprayer shields should be used when 
spraying is done in areas where the plants are still very young. 
(f) Poisoning 
Figure 8.10 Common physical injuries 
216 
Wind Damage 
Rubber trees are also subject to injuries by strong winds. Such damage is common in 
low-pressure areas of Peninsular Malaysia and on susceptible clones such as RRIM 
623, RRIM 701, RRIM 728, RRIM 905, PB 235, PB 254, PB 280, PB 28/59, Nab 17, 
BPM 24 and RRIC 110. Injured trees must be treated immediately before the dead 
tissues become extensive and cause other problems such as fungus infection or insect 
invasion. There are several types of injury resulting from wind damage, namely, branch 
breakage, branch split, crown snap, trunk snap, trunk split and uprooting (Figure 8.11). 
(a) Branch breakage 
Figure 8.11 Types of wind damage (left) and their treatments (right) 
217 
(b) Crown split 
Figure 8.11 Types of wind damage (left) and their treatments (right) 
218 
(d) Trunk snap 
Figure 8.11 Types of wind damage (left) and their treatments (right) 
(e) Crown snap 
Figure 8.11 Types of wind damage (left) and their treatments (right) 
219 
The injured part of the tree must be pruned off. Pruning must be done by 
a sharp pruning saw to obtain a clean cut. Ensure that no crack is seen on the cut 
surface. The cut surface is treated with suitable wound dressing. For the uprooted 
tree, if a reasonable length of the tap root is still good, its end is neatly pruned off and 
wound dressing applied. All the branches, including the main ones, are also pruned 
off and wound dressing applied. The tree is then reinstated. The trunk is immediately 
lime-washed to prevent scorching of the bark. If the affected tree is in tapping, it must 
be rested for six months. 
PESTS 
The rubber tree is also subject to attack by animal pests, which are grouped into three 
- insects, molluscs and mammals. Their brief descriptions, the nature of damage they 
cause and their control are given in the following paragraphs. 
Insects 
Insects, which are defined as small animals from the Insecta class, are made up of three 
body parts, namely head, thorax and abdomen, and three pairs of legs. Those causing 
serious problems to rubber are described below. 
Grasshoppers . Grasshoppers eat away the leaves of legume covers leaving 
only the veins and the young shoots of germinating rubber seedlings. They are active 
during the day. The species Valanga nigricornis is the most destructive. Other common 
species are Xenocatantops humilis, Stenocatantops splendens and three other species 
of Atractomorpha (Figure 8.12a). They can be controlled by spraying with insecticides 
such as Orthene 75S at 1 g + 1 litre water, Tamaron 600 at 1 ml + 1 litre water or 
Malathion LV al 1 kg per hectare applied neat by ultra-low volume (ULV) spraying. 
Crickets. The species of Brachytryptes portentosus and Acheta testacea attack 
rubber. They are active at night, and eat away from the terminal shoot right down the 
base of young rubber seedlings including the collar region. Acheta testacea eat away 
the regenerating bark on the tapping panel (Figure 8.12a). They can be controlled by 
insecticides such as Lindane 20 at 2.5 ml + 1 litre water, Tamaron 600 at 5 ml + 1 litre 
water, Orthene 75S at 1 g + 1 litre water or Malathion LVa\ 1 kg per hectare applied neat 
using the ULV spraying. 
220 
221 
Termites. The species Coptotermes curvignathus can cause serious damage 
to rubber. This species can be identified by its soldier ant that exudes a white fluid 
through an opening in the head, if it is disturbed. They eat away the tap root and into the 
trunk of the tree. They build mudwork over the trunk, and from beneath the casing of the 
mudwork they feed on the bark. Young plants are killed outright, while the older ones 
may survive for some time until blown over by strong winds (Figure 8.12b). Termites 
can be controlled by insecticides such as Dursban EC at 20 ml + 5 litres water, Lorsban 
40 at a 25 ml + 5 litres water, Stedfast at 330 ml + 5 litres water or Fastac at 200 ml + 5 
litres water. The insecticide is poured over the trunk of the affected tree and allowed to 
slip down and into the soil. 
b) Termites 
Figure 8.12 Major insects 
222 
Scale insects. The two types of scale insects that are known to attack rubber 
are the unarmoured scale species of Saissetia nigra and Pulvinaria maxima, and the 
armoured scale species of Lepidosaphes cocculi, Pinnaspis aspidistrae, Phenacaspis 
dilatata, Aspidiouts destructor, Hemiberlesia palmae, Hemiberlesia cyanophylli, 
Parlatoria proteus and Pinnaspis theae. They stick on the stems to suck the sap from 
the plants, weaken them and cause dieback. Very young plants can be killed (Figure 
8.12c-e). They can be controlled by insecticides such as Albarol White Oil at 28 ml + 5 litres 
water or kerosene-soap emulsion at 28 ml + 5 litres water. Kerosene-soap emulsion 
can be prepared by mixing 500 g soap, 4.5 litres water and 28 ml kerosene. 
c) Scale insects 
Figure 8.12 Major insects 
223 
5 mm 
1 mm • r n m 
d) Scale insects 
Figure 8.12 Major insects 
224 
225 
Mealy bugs. Mealy bugs are also sucking insects. The species Ferrisiana 
virgata attacks young shoots, thus causing dieback. Another species Planococcus citri, 
attacks terminal buds, causing distorted stems and crinkled leaves. Both species also 
attack legume covers. The species Icerya, Rastrococcus iceryoides and Dysmicoccus 
sp. attack the under surface of leaves (Figure 8.12f). Control measures are the same 
as those for scale insects. 
f) Mealy bugs 
Figure 8.12 Major insects 
226 
Thrips. Thrips of Sericothrips dorsalis species cause severe defoliation of 
tender leaflets of both young and old rubber. It is common during the annual refoliating 
season, thus contributing to secondary leaf fall. Affected leaflets curl downward like an 
inverted scoop and drop while the petioles are still attached to the plant. Another species, 
Taeniothrips minor, occasionally infests the region of the terminal buds concealed among 
the expanding leaves. Its feeding punctures cause patches of corkiness on the tender 
stem and on the upper surface of the petiole base. Thrips of Heliothrips haemorrhoidalis 
species eat the under surface of older leaf, while Dinothrips sumatrensis are commonly 
found below dead bark (Figure 8.12g). These can be controlled by insecticides such 
as Mitac 20 at 10 ml + 5 litres water, but is rarely required, as the attack usually passes 
with change of weather. 
g) Thrips 
Figure 8.12 Major insects 
227 
Caterpillars. A caterpillar has thirteen body segments and a strong chewing 
mouth. The species Tiracola plagiata, Amsacta lactinea, Orgyia turbata, Mods 
undata, Prodenia litura, Clania variegate, Crematopsyche pendula, Thosea sinensis, 
Adoxophyes privatana, Hyposidra talaca and Euproctis subnotata are known to attack 
rubber. Young leaves are consumed entirely, and the older ones skeletonised. Nacoleia 
(Lamprosema) diemenalis is a serious pest of legume covers. It feeds within folds or 
rolls of leaflets which it binds together (Figures 8.12h and /'). They can be controlled by 
insecticides such as Dipterex sp. at 10 g + 5 litres water or Sevin 85S at 10 g + 1 litre 
water. They rarely need chemical control as they have a lot of natural enemies. 
b, 
h) Caterpillars 
Figure 8.12 Major insects 
228 
229 
Cockchafers. Cockchafer grubs of the species Lachnosterna (Holotrichia) 
bidentata, Psilpholisvestita, Leucopholisrorida, Leucopholis nummicudens, Leucopholis 
tristis, Exopholis hypoleuca and Lepidiota stigma attack rubber. They are voracious 
feeders, nibbling away roots of young rubber and legume covers. As root destruction 
progresses, the leaves turn yellow and fall, shoots dieback and the young tree dies 
(Figures 8.12j-l). They can be controlled by insecticides such as Dursban EC at 20 ml 
+ 5 litres water, Lorsban 70EC ata 25 ml + 5 litres water or Stedfast at 330 ml + 5 litres 
water. Holes are punched in the soil around the plants and the insecticide is poured into 
them. 
j) Cockchafers 
Figure 8.12 Major insects 
230 
5 mm 
k) Cockchafers 
Figure 8.12 Major insects 
231 
232 
Weevils. The species Hepomeces leporinus attacks leaves of young rubber 
and legume covers. Lepropus lateralis eat away leaves of legume covers, while 
Phytoscapus leporinus eat rubber flowers (Figure 8.12m). They can be controlled by 
Tamaron 600 at 25 ml + 5 litres water. 
Smm 
S mm 
s mm 
m) Weevils 
Figure 8.12 Major insects 
233 
Ladybird beetles. The species Epilachna indica destroys legume covers, 
especially Entrosema pubescens, eating away the tissues between the veins, thus 
skeletonising them (Figure 8.12n). They can be controlled by spraying with Sewn 85S 
at 20 g + 5 litres water. 
1 mm 
n) Ladybird beetles 
Figure 8.12 Major insects 
234 
Leaf-eating beetles. Beetles of the Adoretus compressus species eat away 
older leaves until skeletonised, and the species Pagria signata eats away leaves 
of Pueraria phaseoloides and Calopogonium mucunoides, while the Nodostoma 
aeneipenne species attacks Moghania macrophylla (Figure 8.12o). They can be 
controlled by spraying with insecticide, such as Sevin 85S at 25 g + 5 litres water. 
o) Leaf-eating beetles 
Figure 8.12 Major insects 
235 
Mites. The yellow tea-mite of the species hemitarsonemus latus is a common 
insect pest of rubber nurseries. It attacks young rubber leaves, causing severe distortion 
and defoliation whenever new flushes appear. In mature rubber, the newly refoliating 
leaves that appear after wintering are attacked, causing another leaf fall. This pest is 
therefore an agent of secondary leaf fall (Figure 8.12p). They have several natural 
enemies that can help in controlling them. For chemical control, insecticide such as 
Mitac 20 at 25 g + 5 litres water can be used. 
f 
I 
\ 
fy 1 1 A 
I K 
p) Mites 
Figure 8.12 Major insects 
236 
Molluscs 
Molluscs are soft-bodied animals with sole-like feet on which they glide with distinctive 
heads bearing two pairs of tentacles, the longer rear pairs bearing the eyes at the ends. 
They are present in great numbers during the wet season. They attack by night and 
hide during the day, where low vegetation and leaf litter such as the legume covers, 
provide them with good shelter. Their brief descriptions are given below. 
Snails. Snails have protective shells over them. The species Achatina fulica, 
Eulica similaris, Subulina octona and Xestina striata are pests of legume covers and 
rubber, as they eat away the leaves. Snails also climb up tapped trees to suck the latex 
along the tapping cuts, and also cause spillage (Figure 8.13a). They can be controlled 
by poisoned baits consisting of powdered metaldehyde, hydrated lime and rice bran, in 
the ratio of 1:4:6 by weight. The ingredients are mixed together with about the same 
volume of fresh rubber latex diluted in equal volume of water. The mixture is then 
kneaded throughly into crumbs which are air-dried under shade. The poisoned baits 
are spread all over the plantation, especially at the borders of places where they are 
expected to take shelter. 
Slugs. Slugs do not have protective shells over them. The species Mariaella 
dussumieri and Parmarion martensi are capable of damaging young plants. They climb 
up the stems to eat the terminal buds, and when the side shoots appear, these too 
are eaten away. Repeated attacks result in stunted clustered shoots (Figure 8.13a). 
Another slug, Vaginula bleekerie, is more of a legume cover pest, causing extensive 
damage to the foliage and shoots. Slugs also suck latex from tapping cuts of tapped 
trees. Control measures are the same as those described above. 
Mammals 
Mammals are group of animals which are warm-blooded. There are nine of them which 
are pests in rubber cultivation. Brief descriptions of them are given below. 
237 
238 
Deer and mousedeer. There are two deer species namely, Cerva unicolor (the 
sambur deer) and Muntiacus muntjac (the barking deer), while there are also two species 
of mousedeer, Tragulus javanicus (kancil) and Tragulus napu (napuh). They live in the 
jungle but roam the bordering plantation for food. The sambur deer feed on the bark, 
stripping it off from the trunk. Barking deer and mousedeer nibble away the foliage that 
they can reach (Figure 8.13b). They can be kept away by applying repellent substance 
such as Hinder on the trunk, especially on rubber trees bordering the jungle. 
(b) Damage caused by deers and mousedeers 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
239 
Wild boars. Two species are found in Malaysia, namely the common Sus scrofa 
and the bearded Sus barbatus. They eat the cotyledons of germinating seeds, uproot 
young plants and eat away the roots while the bark of older trees are often stripped off 
(Figure 8.13c). Wild pigs can be kept away by perimeter fencing with several strands 
of closely spaced barbed wires and wire netting. They can also be trapped or killed by 
poisoned baits such as zinc phosphide-inserted sweet potato. 
(c) Damage caused by wild boars 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
240 
Rats. Rats come under the group of pests known as rodents. There are two 
rats species attacking rubber, Rattus jalorensis and Rattus argentiventer. Damage 
caused by rats can be serious in areas where the undergrowth are not controlled. 
Rats eat cotyledons of germinating seeds, and nibble away the bark of young plants. 
They sometimes eat the terminal buds, too (Figure 8.13d). They can be controlled 
by rodenticide such as zinc phosphide mixed with suitable bait in the ratio of 1:19 by 
weight. They can also be trapped by applying tanglefoot preparation which is available 
under the trade name of Atom. 
(d) Damage caused by rats 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
241 
Bamboo rats. Bamboo rats are also rodents. Two species, Rhizomys 
sumatrensis and Rhizomys pruinosus, are pests of rubber. Bamboo rats live in burrows 
near thick bamboo clumps. Seedling trees of one to three years old are bitten around 
the collar region until they fall. Stems of smaller seedlings are sometimes cut into short 
lengths and carried into their burrows (Figure 8.13e). They can be caught in cage traps 
using young bamboo shoot or sweet potato as bait. Bamboo rats are protected animals. 
Once caught, they must be handed over to the Department of Wildlife and National 
Parks. 
(e) Damage caused by bamboo rats 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
242 
Porcupines. Porcupines also come under the rodent group. The species 
known as Hystrix brachyura is a pest of rubber. It has a short tail with long sharp pointed 
quills on the body. It lives in the forest but enters the plantation in search of food. It 
feeds on the bark of the rubber tree. Plants are sometimes pulled out of the soil and the 
tap roots eaten away (Figure 8.13f). It can be kept away by perimeter fencing or caught 
in cage trap using salted meat as bait. It is also a protected animal, and must be handed 
over to the Department of Wildlife and National Parks (DWNP). 
(f) Damage caused by porcupines 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
243 
Squirrels. Two species, Callosciurus notatus and Callosciurus caniceps 
are pests of rubber. They are frequently found in plantations where the inter-row 
undergrowths are not controlled. They eat away stems of young rubber seedlings which 
are cut into half way at the base and split upward to expose the pith, which are also 
eaten away. They also consume latex from two to four year old trees and cause bark 
injuries. The teeth mark injuries are spirally made on the stems. They also eat the 
seeds and renewed bark (Figure 8.13g). They can be shot or trapped. 
(g) Damage caused by squirrels 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
244 
Tree shrews. Two species, Tupaia glis and Tupaia minor, attack rubber. They 
closely resemble squirrels. Tender scion shoots are cut and partly eaten away. Similar 
damage to seedlings are also believed to be done by them (Figure 8.13h). They can be 
caught in cage traps or by applying tanglefoot preparation which is available under the 
trade name Atom. 
(h) Damage caused by tree shrews 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
245 
Monkeys. Five monkey species are known to attack rubber. They are 
Presbytis melalopos, Presbytis obscurus, Presbytis cristatus, Macaca nemestrina and 
Macaca irius. Young plantings bordering the forests are frequently attacked. They feed 
on shoots, foliage and young fruits. Branches are broken when they swing on them. 
Seedlings are also pulled out and the tops eaten away. They also bite away the bark 
(Figure 8.13i). They are controlled by shooting. 
(i) Damage caused by monkeys 
Figure 8.13 (a - i) Molluscs, mammalian and pest damage 
Elephants. Elephants cause damage to rubber by eating away the shoots. 
But much damage is caused by their tramplings on crops. They can be kept away by 
electric fencing such as the FELDA Felefence or reported to the Department of Wildlife 
and National Parks for action. 
246 
CHAPTER 9 
LATEX HARVESTING 
TAPPING 
Latex from the rubber tree had been used by the people of Brazil long before Columbus 
crossed the Atlantic. Demand for raw natural rubber started to increase after the 
discovery of the vulcanisation process in 1839. However, production of rubber did not 
increase significantly as there was no large-scale planting of the crop and the method 
of extracting latex from the rubber tree was not systemised. During the period, latex 
was extracted by making indiscriminate incisions on the tree. Such a method resulted 
in excessive wounds on the tree trunk and rendered the trees useless in a very short 
period of time. Conditions became better, when in 1889, H N Ridley discovered the 
excision method of tapping which is still in use until today. This discovery attracted 
large-scale planting of rubber. 
Direction and Slope of Tapping Cut 
Latex flows through latex vessels found in the bark of the rubber tree. Latex vessels run 
spirally from low left to high right at an inclination of 3.7-5° from the vertical. Latex will 
flow out of the bark, only if the latex vessels are severed or cut. The more latex vessels 
are severed, the more will be the flow of latex. Therefore, the tapping cut is made in the 
opposite direction of the latex vessels, that is, from high left to low right (Figure 9.1). 
(a) Position of latex 
vessels in the bark 
(b) Wrong direction 
of tapping cut 
(c) Recommended 
direction of tapping cut 
Figure 9.1: Direction of tapping cut 
247 
The slope of the tapping cut is made at such an angle that gives maximum 
yield with minimum bark consumption and a fast flow of the latex along the tapping cut 
into the latex cup. The tapping cut angle of the slope influences the length and bark 
consumption, which in turn is related to yield. Basically, an increase in the angle of 
slope of tapping cut gives higher yield. Based on experiments, for clonal materials, the 
slope of the cut is recommended at an angle of 30°, while for the clonal seedlings at 25° 
from the horizontal (Figure 9.2). This means that the slope of cut for clonal material is 
5° more than that for the clonal seedling. The bark of the clonal material is generally 
thinner due to less corky layer but contains more latex vessels. Its increased slope is 
to enable the latex to flow faster along the tapping cut, thus avoiding an overflow over 
the trunk. On the other hand, the bark of the seedling tree is thicker. The 25° slope is 
therefore adequate to cause an efficient flow of its latex along the tapping cut. 
(a) For buddings (b) For clonal seedlings 
Figure 9.2: Angle of tapping cut 
Height of Tapping Cut 
For the clonal materials, the recommended height for opening of tapping panel is 150 
cm, while the seedling materials it is 75 cm from the ground level (Figure 9.3). Clonal 
materials are opened much higher than seedlings because of their cylindrical shaped 
trunks. Furthermore, there is no significant variation in yield when opened tapped at any 
height on the trunk. Therefore, the tapping cuts are open as high as possible on the 
trunk. On the other hand, the trunks of seedlings taper upward, as a result, more latex 
vessels can be found lower down the trunk. The tapping cuts on seedlings are therefore 
opened as low down the trunk as possible. For both types of planting materials, the 
trunk girths must attain 45 cm at opening of tapping panels at their respective heights. 
(Figure 9.3). 
248 
—X 45 cm 
150 cm 45 cm -r— 
75 cm 
a b 
(a) For buddings (b) For clonal seedlings 
Figure 9.3 Height of opening of tapping panel and girth size 
Task Size 
Task size is the number of trees in a task given to a tapper to complete tapping at a 
specified time. The number is based on several factors such as girth size, density 
per hectare, tapping system and the topography of the area. Basically, when tapping 
alternate daily, at half spiral, a tapper is given 500-600 trees per day of tapping task. 
Time of Tapping 
Tapping is carried out as early as possible in the morning and that is why it is always 
referred to as dawn tapping. Though no time is specified, it starts as soon as the tapping 
panel is clearly visible without the use of aided light. As the full impact of sunlight is 
not yet present, transpiration rate is still very low. Thus the cells of the rubber trees are 
still in turgid condition and, therefore, effect an efficient flow of the latex in the vessels. 
The turgor pressure within the tree is also high during this period, thus resulting in a 
faster flow of the latex. When tapping is done along the tapping cut, the ends of the 
latex vessels are again severed and latex oozes out along the cut and drips into the 
cup. After some time, the drip stops due to the plugging of the latex vessel ends by 
coagulated latex (Table 9.1). 
249 
TABLE 9.1 QUANTITY OF LATEX FLOW BY TIME OF TAPPING 
Time of tapping Quantity of latex per tree (ml) 
0400 155 
0830 129 
1230 112 
Depth of Tapping 
The bark of the rubber tree is made up of several layers. The outermost is called the 
corky bark, which acts as a protective layer. In the second layer, which is the hard 
bark stone cells and several unorganised latex vessel rings can be found. The greater 
number of latex vessel rings are found in the soft bark, which forms the third layer. The 
latex vessels in the bark are in rings which are closer to one another as they reach the 
wood. Between the bark and the wood is the cambium layer, with the medullary rays 
running horizontally across the bark (Figure 9.4). 
HARD BARK SOFT BARK 
Consisting of stone cells, Consisting mainly of vertical 
parenchyma and disorganised rows of sieve tubes 
Figure 9.4 Three dimensional cross-section of the bark of the rubber tree 
250 
Tapping requires skill, which can be acquired by constant practice. The efficiency 
of the tapper can influence the yield obtained. As the number of latex vessel rings are 
greater towards the inside, tapping must be deep enough to sever as many latex vessels 
as possible (Table 9.2). However, to avoid contacting the cambium, 1 mm of bark 
should be left untapped. This will enable faster renewal of bark (Figure 9.5). Tapping to 
adequate depth can give three times the amount of yield compared to shallow tapping. 
On the other hand, too deep tapping results in lower dry rubber content (DRC) of latex, 
because the resultant latex gets mixed up with water from the cambium layer. Too deep 
tapping also damages the cambium and this result in wounds, and uneven renewed 
bark, rendering tapping difficult later on. If tapping has been done well, the regenerated 
bark is smooth and should be thick enough for retapping in six years' time. 
TABLE 9.2 RINGS OF LATEX VESSELS SEVERED BY DEPTH OF TAPPING 
Depth of tapping (mm from cambium) Number of latex vessel rings severed 
2.0 38 
1.5 48 
1.0 62 
0.5 80 
Figure 9.5 Cross-section of the bark showing depth of tapping 
251 
Thickness of Tapping 
Latex can only be found in the latex vessels, which have to be severed for the latex 
to flow out. This can be done by slicing away the bark. The same amount of latex is 
obtained irrespective of the thickness of the bark removed. But a thick slice definitely 
removes a lot of bark and this reduces the economic life of the tree. Therefore, good 
tapping is to just remove the plugs at the ends of the latex vessels severed during the 
previous tapping (Figure 9.6). It is estimated that, for alternate daily tapping, only 1 mm 
thickness of the bark is required to be removed in order to achieve a satisfactory flow 
out of latex. As a guide, the yearly bark consumption is given in Table 9.3. Spot marks 
can be made on the tapping panel on the first day of each month to show the thickness 
of bark consumed in a month. To prevent excessive consumption of bark, spot marks 
on the bark to be consumed monthly are placed on the untapped panel instead. This 
can be easily implemented by using a rollmarker (Figure 9.7). 
TABLE 9.3 YEARLY BARK CONSUMPTION GUIDE 
Frequency of tapping Type of bark Thickness of bark consumed (cm) 
Alternate daily Virgin 20-25 
Renewed 25-30 
Third daily Virgin 18-20 
Renewed 20-25 
Corky bark 
^ x : x : : : : : : : 
^ £ x x x - x : x -/^Avx-x-x-x-x-: 
Boundary of next tapping 
Cambium-
1 mm bark left untapped 
Plugs of latex 
ox':<:x-x:::x:x-x"::i::::::>-| 
::::x:X;::X:X:X:::x::::Jx:x::|: 
'•"•""'-"•'•••"•'""•"£^ XvX*X*Sv 
i i i i i i i i i i i i l i l * 
II 
Figure 9.6 Cross-section of the bark showing thickness of tapping 
252 
(a) Thickness of bark consumed 
(b) Thickness of bark to be consumed 
Figure 9.7 Monthly bark consumption guide markings 
Tapping Knife 
The tapping knife is considered a very important item, as it assists in determining the 
depth and thickness of tapping. It must be sharp enough so as to enable it to slice away 
efficiently optimum amount of bark. On the other hand, a blunt knife needs greater force 
to pierce it into the bark, rendering it difficult to control and finally causing damage to the 
cambium. Basically there are two types of tapping knife - the one that cuts by pushing 
known as gouge, while the one that cuts by pulling, known as jebong. The jebong knife, 
if sharpened at both ends has dual functions of pushing and pulling, and is also known 
253 
as bidirectional tapping knife. A modified gouge is needed for upward tapping and the 
controlled upward tapping (CUT) is suitable for this purpose. A prototype motorised 
tapping knife using battery power named Motoray was invented during the 1980's. 
However, it is not in use currently. Figure 9.8 shows the development of the tapping 
knife from the early U-shaped gouge to the modern battery-powered Motoray. 
Figure 9.8 Development of tapping knives in Malaysia 
Disturbance of Rain Towards Tapping and Yield 
In Malaysia, rainfall considerably upsets tapping and production. Rain water that flows 
down the trunk from the crown causes the panel to be wet and upsets the flow of latex 
along the tapping cut when tapping is done the following morning. Fixing a rain guard 
over the panel can overcome such problem (Tafo/e 9.4). This was introduced in 1989 
and given the trade name of RRIMGUD. Subsequently, another improved rain guard 
made from bitumen based material was introduced. This is called the raingutter and is 
currently available in the market. (Figure 9.9). 
254 
TABLE 9.4 ADDITIONAL TAPPING DAYS AND YIELDS OBTAINED 
WITH THE USE OF RRIMGUD 
Item 
Site A (2 months) Site B (2 months) 
Control RRIMGUD Control RRIMGUD 
Total no. rainy days 19 99 
Tapping days: 
Dry and tappable 31 29 185 185 
Saved from rain 
interference - 12 - 9 
Total 31 41 185 194 
Yield (kg): 
Dry and tappable 284 233 4,108 4,300 
Saved from rain 
interference - 85 - 247 
Total 284 318 4,107 4,547 
Site A : Clone PR 255, PR 261 and GT 1 
Site B : Clone PB 260 
Figure 9.9 Rainguard 
255 
TAPPING CENSUS 
Rubber tree girths are measured from time to time to determine the time of opening for 
tapping. This operation is in fact a continuation of the growth census which starts when 
the trees are one year old. Tapping census or survey commences when the girths have 
reached 35 cm, or approximately three and a half to five years after planting. 
The girth of each tree is measured at a height of 150 cm for budded clones and 
75 cm for seedlings, from the ground level. Trees with girths of 45 cm and above are 
given three dots, less than 45 cm but more than 40 cm two dots and those below 40 cm 
but more than 35 cm one dot. Using black paint, the dots are placed on the tree trunks 
at the height of measurement. They are circular in shape of 1 cm in diameter arranged 
vertically at 0.5 cm apart (Figure 9.10). The census is repeated every three months 
until the trees with two dots and one dot attain the girth of 45 cm or more (three dots). 
Usually, tapping can commence when 70% of the stand attain 45 cm girth. 
<35 cm 
I 
o 
"»" 
35-<40 cm 40-<45 cm 45 cm or more 
Figure 9.10: Girth size marking 
256 
OPENING OF TAPPING PANEL 
Rubber trees are opened for tapping when their trunks have attained 45 cm girth, 
measured at a height of 150 cm for clones and 75 cm for seedlings from the ground level. 
In determining the maturity of the rubber tree, age is not considered; the most important 
factor being that the trunk has attained the required girth size, which is estimated to be 
in five years or less. 
Girth Measurement 
If tapping census or survey had been carried out earlier, trees with 45 cm girth sizes 
are already known. Otherwise, the girths have to be measured. This is done using a 
piece of wooden 'beroti' 150 cm in length with a piece of wire of 45 cm in length fixed 
at one end. The 'beroti' is placed upright against the tree trunk with the bottom end 
at ground level and the wire wrapped around the trunk. If the ends of the wire do not 
meet, the girth of the tree is taken as more than 45 cm. Each tree is measured in the 
same manner to determine the minimum 70% of trees for the opening of tapping. For 
the seedlings, the procedure is the same (Figure 9.11). 
Figure 9.11 Girth measurement 
257 
Marking the Slope of the Tapping Cut 
To mark the tapping cut on the tree trunk, a template is required. This is done by using 
a piece of wooden 'beroti' of 150 cm in length for clones and 75 cm for seedlings, with 
a piece of zinc plate 40 cm long and 5 cm wide fixed at one end. The zinc plate is 
horizontally fixed at an angle of 30° for clones and 25° for seedlings. The 'beroti' is 
placed upright against the tree trunk with its bottom end at ground level and the zinc 
plate wrapped around the tree trunk towards the left. Using crayon or nail, a mark is 
made along the top edge of the template and continued down along the beroti right to 
the base of the trunk (Figure 9.12). The tapping cut is made on half the circumference 
of the trunk. This is done by wrapping a piece of string around the trunk at 150 cm or 75 
cm from the ground level, and folding it equally into two. The folded string is stretched 
across the trunk with one end at the corner of the slope and the left end of the string 
marked. This measurement is repeated at lower down the trunk to ensure that the trunk 
circumference is properly halved. A straight 'beroti' is placed against the tree trunk to 
meet both half circumference marks. Using crayon or nail, a mark is made along the 
'beroti', from the top edge right down to the base of the trunk. The temporary panel 
border line that has already been marked on the trunk is then made permanent by a thin 
shaving of the bark along it, using the tapping knife. Using the rollmark, the amount of 
bark to be consumed monthly is marked out on the panel for the first eighteen months. 
To complete the operation, a spout, hanger and cup are fixed in position (Figure 9.13). 
(a) Template (b) Determining the slope (c) Marking the slope 
Figure 9.12 Determining slope of tapping cut 
258 
(a) Measuring half trunk circumference 
H 
(b) Measuring half trunk circumference 
at the bottom of the tree 
(c) Shaving bark along slope 
259 
(d) Shaving bark along slope 
and boundary marking 
The spout is normally fixed at 20 cm below the tapping cut. This serves as an 
indication of a year's bark consumption for 1/2 Sd/3 tapping system. It is moved 20 cm 
downward again when the tapping cut reaches the spout. The spout should not be hit 
too hard into the wood to avoid damaging the cambium. The hanger is placed below 
the spout; the distance should be convenient enough to remove the latex cup without 
knocking the spout. Cup hangers with springs are preferred. 
RRIMCAP 
RRIMCUP 
Figure 9.14 PVC latex cup fitted with lid and funnel 
known as RRIMCUP 
Leaning trees are sometimes present in the plantation, especially in peat soil 
areas. Unlike in the case of the normal upright trees, there are certain procedures to be 
followed when leaning trees are opened for tapping. This is to prevent spillage of the 
latex. These procedures are illustrated in Figure 9.16. 
261 
(a) Leaning to the right (b) Leaning to the left (c) Too much leaning 
Figure 9.15 Position of tapping panels and latex cups for leaning trees 
TAPPING AND COLLECTION 
Good tapping and collection procedures are essential to obtain maximum yield. In 
addition, cleanliness is also important in obtaining clean raw materials and finally high 
quality finished products. 
Procedure of Tapping 
Tapping commences as early as possible in the morning. When the rubber tree is not 
in tapping, the latex cup should preferably be in the inverted position so that is does 
not collect dirt and water. Otherwise, the tapper must first clean the cup by removing 
scrap rubber and whatever foreign materials present in it. The cup is then replaced on 
its hanger in the inverted position. The tree lace is then removed from the tapping cut 
and spout, and placed in a special container. Using the sharp tapping knife, a thin slice 
of the bark is removed along the full length of the tapping cut until latex is seen oozing 
out. The cut of the bark must be deep enough without affecting the wood. The latex cup 
can now be put in its proper position for the latex to drip into it. The same procedure is 
applied to the rest of the trees. Tapping is carried on until all tappable trees in the task 
have been tapped (Figure 9.16). The latex is allowed to drip until it stops. 
262 
Figure 9.16 Tapping a rubber tree. A pulling cut is made right down to the bottom corner of the panel 
263 
Collection of Latex 
Generally, latex is only collected when it stops dripping. This may take two to three 
hours, depending on various factors. Collection commences when the first few tapped 
trees cease dripping. During collection, the latex is completely scooped out of the cup 
and poured into the collecting bucket. The cup is then replaced on the hanger in the 
inverted position, unless late drip is anticipated. Collection is continued until latex from 
all tapped trees in the task is collected. The collected latex is immediately sent to the 
collecting centre or factory for processing. (Figure 9.17). 
(a) Collecting of latex only when dripping stops 
(b) Pouring latex completely into a collecting tank 
Figure 9.17 Collection of latex 
264 
In tapping and collection, cleanliness must always be practised to avoid 
contamination of the latex. This can be achieved by ensuring that all pieces of equipment 
used, such as tapping knife, spout, cup, polybag, bucket and churn are clean. From 
time to time, the trees also need cleaning from moss and bits of dried bark. Scrap 
rubber collected in the field must not be mixed with the latex . The collected latex must 
always be kept covered. All these steps are necessary to avoid contamination of the 
latex with dirt and also to prevent the latex from precoagulation which makes further 
processing almost impossible. If necessary, anticoagulants are used to keep the latex 
in stable condition before processing. 
EXPLOITATION SYMBOLS 
Symbols can be defined as abbreviations of words, especially for the long ones. 
Exploitation symbols are abbreviations used for describing the methods of exploitation 
system. These symbols have been agreed to by the international rubber planting 
community, to facilitate communication. They were first introduced in 1939, but the 
complete set of symbols was established only in 1982 by the International Rubber 
Research and Development Board (IRRDB). 
Cut Symbols 
Tapping by cutting involves the operation of slicing away the bark to release the latex 
from the vessels. The symbols used are in the form of letters as shown below: 
S = Spiral cut 
V = V cut (a tapping cut in the shape of the letter V) 
C = Circumference cut (a tapping cut, the type of which is not 
specified) 
Mc = Mini cut (a tapping cut the length of which is less than 5 cm) 
265 
Length of Cuts 
The length of a tapping cut is interpreted as the relative proportion of the trunk 
circumference that is embraced by the tapping cut and does not refer to the actual 
length. The length of cut is represented by a fraction before the symbol, except for a 
mini cut, the length of which is given in centimetres. 
s One full spiral cut 
V One full V cut 
c One full circumference cut 
1/2S = One-half spiral cut 
1/3V = One-third V cut 
3/4S = Three-quarter spiral cut 
1/2C = One-half circumference cut 
Mc2 = Mini cut with 2 cm length 
SR = One full spiral cut 15 cm less than one full circumference 
Number of Cuts 
A number of tapping cuts can be made on a tree. These are either tapped on the same 
day or on alternate tapping days. The number of cuts is represented by a figure written 
before the symbols as shown below. 
• 2x1/2S = Two half spiral cuts 
• 3x1/2V = Three half V cuts 
4xMc2 = Four mini cuts of 2 cm in length. 
Frequency of Tapping 
Forthe actual frequency, the symbol is a fraction of the time unit of day (d). The numerator 
of the fraction is d without any number before it and denotes the tapping period (day), 
while the denominator denotes the tapping interval of the actual frequency in days or in 
fraction of a day as listed below: 
• d/1 = Daily 
d/2 = Alternate daily (one day in two) 
d/3 = Third daily (one day in three) 
d/4 = Fourth daily (one day in four) 
• d/6 = Sixth daily (one day in six) 
d/0.5 = Twice daily 
266 
Fot the practical frequency, a fraction is written after the actual frequency, where 
continuous tapping is broken by regular day or days of rest. This fraction showing the 
frequency as a numerator as the number of days tapped in the period denoted by the 
denominator. 
Periodicity 
The symbol of periodicity may consist of one or more fractions in the time unit of weeks 
(w), month (m) and year (y). The numerator of each fraction denotes the tapping period 
and may be with or without numeral before the symbol, while the denominator of each 
fraction denotes the length of the cycle (tapping period + rest). Each succeeding fraction 
in the periodicity symbol modifies the period of operation of the previous fraction, the 
denominator of the trial fraction gives the full cyclic period of the system. 
• 2w/4 = Two weeks in tapping followed by two weeks of rest 
6m/9 = Six months in tapping followed by three months of rest 
2w/4 6m/9 = Two weeks in tapping followed by two weeks of rest 
Bark and Panel 
The tapping panel is the area of bark where the tapping cut is made. The panel symbols 
describe the location of the panels and the type of bark as listed below: 
d/2 6d/7 
d/1 2d/3 Daily tapping , two days in tapping followed by one 
day of rest 
Alternate daily tapping, six days in tapping followed 
by one day of rest 
during six months followed by three months of rest 
O Virgin bark 
First renewed bark 
Second renewed bark 
Third renewed bark 
Base panel (150 cm and below) 
High panel (150 cm and above) 
Base panel, virgin bark, first panel 
Base panel, first renewed bark, third panel 
Base panel, second renewed bark, second panel 
High panel, virgin bark, fourth panel 
II 
III 
B 
H 
BO-1 
BI-3 
BII-2 
HO-4 
267 
Direction of Tapping 
The direction of tapping can either be downward or upward. For tapping downward, no 
direction symbol is used. For upward tapping, an upward arrow (|) sign is shown after 
the cut symbol. When two directions of tapping are applied on a tree, both direction 
symbols ( | | ) are shown after the cut symbols. 
i 
t 
Ti 
1/2 S 
1/4ST 
2x1/2Vt| 
3/4C1/2VT1/4VJ = 
Change-over System 
Downward tapping (usually not written) 
Upward tapping 
Upward and downward tapping 
One half spiral cut tapped downward 
One quarter spiral cut tapped upward 
two half V cuts, one tapped upward and the other one 
tapped downward 
Three-quarter circumference cut, one half V cut tapped 
upward and one quarter cut tapped downward. 
Tapping may continuously be done on one panel or a group of panels, tapped on the 
same tapping day. It can also be done on several panels or on several groups of panels, 
each tapped on alternate tapping period. The latter is known as change-over system 
and is denoted by the cycle of changes of each tapping panel given within brackets. The 
first figure within brackets indicates the cycle of change of the second tapping panel. 
A comma (,) is inserted between a cycle of change of the tapping panels. The cycle 
of change tapping is denoted by the tapping panels. The cycle of change tapping is 
denoted by the symbol t (tapping), w (week), m (month) and y (year). 
• (t,t) = Two cuts, each tapped alternately at every tapping 
(w,2w) = Two cuts the first tapped for one week followed by the 
second cut tapped for two weeks 
(6m, 6m) = Two cuts, each tapped alternately at every six month 
Combination Tapping 
Combination tapping describes the use of different length and types of cut on the same 
tree. Such tapping can be done on the same tapping day or on alternate tapping days. 
268 
When the trees are tapped by the combination tapping system on the same 
tapping day, the symbols for the system are joined by a plus (+) sign. 
1/2S+1/4S t = A half spiral cut downward, tapped on the same 
tapping day with a quarter spiral cut upward. 
1/4S+1/4V = One quarter spiral cut downward, tapped on the same 
tapping day, with one quarter V cut downward. 
When the trees are tapped by combination tapping on alternate tapping day, the 
symbols for the system are separated by a comma (,) sign. 
1/2S.1/8S t = One half spiral cut downward, tapped on alternate 
tapping day with one-eighth spiral cut upward. 
1/4S.1/4V = One quarter spiral cut downward, tapped on alternate 
tapping day with one quarter V cut downward. 
Stimulation Symbols 
Stimulation also has its symbols in terms of active ingredients, concentrations, quantity 
applied, method and frequency of application. They also form part of the tapping 
symbols. 
ET Ethephon 
ET 5.0% Ethephon at five percent concentration 
Ba Bark application 
Pa Panel application 
Ga Groove application 
La Lace application 
m = Monthly application 
y Yearly application 
4/y Four yearly applications 
Examples of Full Exploitation System Symbols 
• 1/2S d2 
One half spiral cut downward, tapped alternate daily 
269 
• 1/4f d/2 8m/12ET5.07o8/y 
One quarter spiral cut upward, tapped alternate daily for eight out of twelve 
months, stimulated with ethephon at five percent concentration, eight times 
a year. 
• 1/4S d/1 (t,t) 2d/3 8m/12 ET2.5% 2/y 
Two one quarter spiral cuts downward, tapped daily on alternate tapping two 
out of three days, eight out of twelve months, stimulated with ethephon at two 
and a half percent concentration, twice yearly. 
• 1/4St+1/2Sd/3ET5.0%12/y 
Two cuts tapped on the same tapping day, one quarter spiral cut upward and 
one half spiral cut downward tapped third daily, stimulated with ethephon at 
five percent concentration, twelve times a year. 
LATEX YIELD STIMULATION 
Efficient latex harvesting systems are prerequisites to obtaining high and sustainable 
tree productivity, tapper productivity and land productivity with minimal deleterious 
effect on latex production and tree growth throughout the economic life of the Hevea 
trees. The most effective chemical as latex stimulant was found in the late sixties with 
the discovery of 2-chloroethylphosphonic acid that has the property of decomposing 
gradually in the presence of water, releasing ethylene gas as an active ingredient. In 
Malaysia, ethephon was introduced for commercial adoption in the early 1970s. In the 
late eighties, another development took place. A low intensity tapping system (LITS) 
concept was introduced to address low rubber production mainly because of tapper 
shortage, productive rubber areas left idle and low tree productivity, tapper productivity 
and land productivity issues. In general, LITS consists of exploitation systems with 
tapping intensity less than that of the conventional tapping system and where stimulation 
is one of the most critical components. Stimulation is a method to increase tapping yield 
of Hevea trees by prolonging latex flow with or without the use of chemicals. Increasing 
land to man ratio is an effective approach adopted in the LITS concept, to reduce the 
requirement of tappers and to increase tapper efficiency. 
Subsequently, gaseous stimulation was developed and introduced to the NR 
industry during the 1990s in combination with "short cut" tapping system. At present, 
270 
conventional ethephon stimulation has its limitations whilst gaseous stimulation is 
recommended only for 15 year-old and older Hevea trees where tapping on both BO-1 
and BO-2 panels have been completed. The various latex stimulation techniques 
recommended by MRB are described in detail below. 
Ethephon (ET) and Ethephon-Based Formulations 
Ethephon 
Currently, ethephon is intensively used and is mixed with carriers such as palm oil and 
water. Ethephon, through the ethylene it releases, delays the plugging mechanism in 
latex vessels, thereby enabling longer latex flow (Table 9.5). 
TABLE 9.5 EFFECT OF ETHEPHON STIMULATION ON YIELD 
Clone Tapping 
system Panel 
Period 
(year) 
Yield (kg/ha) 
Control Bark Groove Lace 
RRIM 600 1/2S d/2 BO-2 4 8,885 12,798 9,988 9,196 
RRIM 701 1/2S d/2 BO-1 4 7,824 7,296 9,553 8,536 
GT 1 1/2S d/2 BO-1 3 4,121 7,261 8,418 7,998 
GT 1 1/2S d/3 BI-2 3 4,609 6,562 6,435 6,819 
PB 5/51 1/2S d/3 BI-1 9 11,490 13,239 14,327 13,556 
RRIM 623 1/2S d/3 BI-1 10 16,474 22,608 25,106 23,640 
RRIM 605 1/2S d/3 BI-1 10 14,015 20,932 22,842 22,836 
Note: Ethephon @ 5.0% was applied on the bark bi-monthly, on the groove and lace monthly. 
The stimulant has to be in contact with the bark for a stated period of time 
to attain the effective response. Once a response has been initiated, immediate re-
application of ethephon has no effect, except after a lapse of a few days between the 
first and subsequent application. 
271 
ET2.5% ET5.0% ET10% 
Figure 9.18 Concentration of ethephon available in the market 
Apart from that, weather also influences the effectiveness of ethephon. 
Moderate to heavy rain after application affects the yield response because it removes 
the stimulant from the site on the tree. Therefore, it is advisable to re-apply if it rains less 
than 6 hours after stimulation. Less frequent stimulant application is suitable for younger 
trees tapped on virgin bark and more frequently on older trees tapped on renewed bark 
and for upward tapping. 
Ethephon is available in the market at concentrations of ET 2.5% (blue), ET 
5.0% (green) dan ET 10% (red) (Figure 9.18). 
Method of Application 
There are several methods of stimulant application. They are the bark, panel, groove, 
lace and the combined application methods. Brief descriptions of each method are 
given below. 
Bark application. A 3.8 cm strip of bark is scraped below the tapping cut just 
to remove the corky layer (no latex should ooze out), ethephon at 1.0-1.5 g is brushed 
on evenly over the scraped bark. The treated bark is tapped away within two months. 
(Figures 9.20). 
Panel application. Ethephon at 0.5-1.0 g is brushed on evenly over 1.25 cm 
strip of bark just above the tapping cut (Figure 9.19). Such application lasts for one 
month. This method can only be recommended if the panel is not to be retapped. 
272 
Groove application. After removing the thick tree lace, ethephon at 0.5-1.0 g 
is brushed evenly only over the tree lace along the tapping cut and part of the tapping 
panel (Figure 9.20). This application lasts for one month. 
Lace application. Ethephon at 0.5-1.0 g is brushed on evenly over the tree lace 
along the tapping cut and part of the tapping panel (Figure 9.19). This application lasts 
for one month. 
Bark and lace application. This combination method is specially recommended 
for trees tapped on the ultra low frequency tapping system of sixth daily (d/6). Ethephon 
is applied over the lace as usual and on a 6-mm strip of scraped bark below the tapping 
cut. A total of 1 g of stimulant is used per tree. The application also lasts for a month. 
Stimulation by applying ET on the rubber lace. 
Recommendation: For conventional tapping system 
(1/2S) with tapping intensity d/3 dan d/4. 
Stimulation by applying ET on the 
scraped bark (Ba), tapping slope (La) and 
tapping panel (Pa). Recommendation: 
For the Low Intensity Tapping System 
the tapping frequency is once every six 
days (LIT d/6). 
Figure 9.19 Ethephon application techniques 
Rate of Ethephon Usage 
The rate of ethephon usage is between 0.5 to 1.0 g per tree for each application, except 
for the LIT d/6 system. For the LIT d/6 system, a higher amount is applied, i.e. between 
0.75 to 1.5 g per tree. However, one should bear in mind that a higher rate of application, 
i.e. above the recommended amount will not give any incremental effect to the rubber 
yield since the yield is influenced by other activities such as tapping, physiology of the 
tree, chemical concentration and rate of application of ethephon. 
273 
Preparation of Low Concentration of Ethephon 
Low ethephon concentrations such as ET 1.5% dan ET 3.3% are still not available in 
the market. 1.5 % ET concentration is recommended for young rubber trees which 
have recently been opened for tapping and for tapping on panel BO-1 (Table 9.8). On 
the other hand, a 3.3% ET concentration is recommended for tapping on panel BI-1 
while 5.0% ET for panels on BI-2 and HO. The items required for the preparation of 
ET 1.5%, 3.3% and 5.0% concentration are commercial ethephon (ET 2.5%, ET 5.0% 
dan ET 10.0%) and clean water. 
TABLE 9.6 THE PREPARATION OF LOW CONCENTRATION ETHEPHON 
Required 
concentration of 
ET(%) 
Rate of mixing commercial ET 
with water 
Number of trees that can be 
stimulated from 500 ml ET 
1.5 ET 2.5%: Water (3:2) 800 
2.5 ET 5.0%: Water (1:1) 1,000 
3.3 ET5.0%:Water (2:1) 700 
5.0 ET 10%: Water (1:1) 1,000 
Note: Concentration of ET 5.0% to ET 1.5% or ET 10% to ET 1.5% and ET 2.5% is not recommended since 
the concentration will be too thin and wil easily flow out from the tapping cut/groove. 
Important Points to Remember: 
i. The amount of ET 1.5%, ET 3.3% and ET 5.0%, must be prepared in accordance 
to the number of trees to be stimulated. For example, in the preparation of ET 
1.5% for 500 trees: the amount of ET 2.5% required is 300 g while the quantity 
of water is 200 ml. Hence, one 500 g bottle of ET 2.5% can be reduced in 
concentration from ET 2.5% to ET 1.5% and applied for 800 trees. 
ii. Low concentrations of ET (ET 1.5%, ET 3.3% and ET 5.0%) must be prepared 
on the same day just before application. It is not encouraged to keep prepared 
low concentrations of ET for the following next application. 
iii. The chemical cost of low concentration ET for each application is less than or 
up to 1 sen. For example, assuming the cost of ET 2.5% is at RM 5.00 per 500 
g bottle. Once the concentration is reduced to ET 1.5%, the cost of application 
per tree is 0.6 sen. In the case of ET 5.0% reduced from ET 10% concentration, 
the cost is 1 sen per tree (based on price of ET 10% at RM 10.00 per 500 g 
bottle). 
274 
Table 9.7 provides the guidelines for ethephon stimulation in terms of tapping system 
and schedule which need to be adhered to for optimum results. 
TABLE 9.7 GUIDELINE FOR ETHEPHON STIMULATION 
Tapping 
system 
Stimulation schedule 
Panel Initial 
Option 
Option 1 Option 2 
1/2S d/2 ET1.5%La2/y ET1.5%La 3/y ET 2.5% La 2/y 
1/2S d/3 ET1.5%La3/y ET 1.5% La 4/y ET 2.5% La 3/y 
BO-1 1/2S d/4 ET 1.5% La 6/y ET 1.5% La 8/y ET 2.5% La 6/y 
1/2S d/6 ET1.5%La 12/y - ET 2.5% La 12/y 
1/2S d/2 ET 2.5% La 3/y ET 2.5% La 4/y ET 3.3% La 3/y 
1/2S d/3 ET 2.5% La 4/y ET 2.5% La 6/y ET 3.3% La 4/y 
BO-2 1/2S d/4 ET 2.5% La 8/y 
- ET 3.3% La 8/y 
1/2S d/6 ET2.5% La 12/y - ET3.3% La 12/y 
1/2S d/2 ET 3.3% La 6/y ET 3.3% La 8/y ET 5.0% La 8/y 
1/2S d/3 ET 3.3% La 8/y - ET 5.0% La 8/y 
BI-1 1/2S d/4 
1/2S d/6 
ET 3.3% La 12/y - ET 5.0% La 8/y 
ET 5.0% La 12/y 
HO-1 to 
HO-3 
1/4Sf + ET, 
1/2S d/2-ns 
(8:4) 
ET 5.0% La 8/y - -
1 year 
before 
felling 
1/4ST + ET + 
1/2S + ET or 
1/2S| + ET + 
1/2S + ET 
ET 10% La 12/y 
ET 10% La 12/y 
- -
Option 1 : If the yield response is less than 10% of targeted yield (yearly) 
Option 2 : If the yield response is less than 15-20% of targeted yield (yearly) 
Clones That Respond Positively to Stimulation 
Generally most of the RRIM 900 Series clones (except RRIM 921 and RRIM 916) give 
encouraging response to ethephon stimulation while the PB Series clones give less 
response. The PM 10 clone is categorised as giving medium response to ethephon. 
Clones such as RRIM 600, RRIM 605, RRIM 623, GT I dan PR 261 give medium to 
good responses. 
275 
Ethephon-Based Stimulant, MORTEX 
MORTEX 2.5% Increased and stabilised yield with 
MORTEX stimulated trees 
Figure 9.20 Ethephon-based stimulant, MORTEX 
In the year 2004, MRB launched an improved version of the ethephon-based latex 
stimulant (EBS) known commercially as MORTEX. The method of application is the 
same as that of ethephon but allows more frequent application (8-9 times/year) on young 
rubber right from the opening of tapping on panel BO-1 (Figure 9.20). 
Objectives 
MORTEX is used to obtain higher stable yields with minimum side-effects especially for 
young rubber trees tapped on base panels. It can also be used for premium trees. 
Application Technique 
Figure 9.21 Applying MORTEX on the groove 
MORTEX is applied on the groove along the tapping cut/slope covering <1.0 cm of the 
renewed bark on the upper end of the tapping slope using a suitable painting brush. 
(Only thick tree laces are to be removed prior to application) (Figure 9.21). 
276 
Rate of MORTEX Application 
The rate of MORTEX application is 0.5-1.0 g per tree. Any application above the 
recommended amount will not give any noticeable effect to latex yield. Hence, for 
economic and practical purposes, it is advised that MRB's recommendation is adhered 
to (Table 9.8). 
Important Points to Remember: 
• In order to ensure continuous high yields, trees stimulated with MORTEX must 
be maintained and fertiliser applied according to schedule while adopting the 
recommended tapping system. 
• Avoid using MORTEX during wintering months. 
• Do not mix MORTEX with other chemicals. 
Note: 
Clones that give good response to ethephon give the same response to MORTEX. 
TABLE 9.8 RECOMMENDATION OF MORTEX APPLICATION 
Tapping panel Frequency of annual application 
BO-1 Six to eight times a year and rest during the wintering months 
BO-2 Eight to nine times a year and rest during the wintering months 
BI-1 Nine to ten times a year and rest during the wintering months 
Gaseous Stimulation 
RRIMFLOW (RF) and REACTORRIM (RR) are stimulation techniques applying the 
concept of supplying gaseous stimulant (ethylene gas) into laticiferous tissue of 
the rubber tree with different kinds of equipment. RF adopts intermittent gassing 
with supply of ethylene gas carried out every ten days while RR adopts a slow but 
continuous release of ethylene gas from a reactor bottle. The release of ethylene 
gas from the RR canister is regulated by a microporous membrane (MPM). Both 
stimulation techniques produce comparable tree productivity, approximately two to 
277 
three times that of conventional tapping systems without any stimulation. These 
tapping systems are recommended for high tapping panels of premium Hevea trees 
(5 15 year old with both panels BO-1 and BO-2 already tapped) or older but are not 
suitable for younger Hevea trees, panels BO-1 and BO-2. 
There are many types of old clones that respond favourably to this technique. 
Among them are GTI, RRIM 600, RRIM 623, RRIM 605, PB 261 and PB 217. Clones 
PB 28/59, PB 310 and seedling stocks are found to be less responsive to gaseous 
stimulation. 
Currently MRB recommends three gaseous stimulation techniques using 
ethylene gas supplied directly into the laticiferous tissue of the rubber tree, viz. RR, RF 
and G-FLEX for trees that are 15 years old and above with both tapping panels (BO-1 
dan BO-2) completely tapped. These trees must fulfill the following criteria: 
• Healthy 
• Disease-free 
• Adequate fertiliser application as recommended 
• Clones that give positive response to ethephon 
• Good bark on panel HO 
• No indiscriminate tapping 
Normally with the use of ethylene gas, the DRC drops by 2-5% due to the latex 
becoming more fluid compared to conventional system. The duration of the flow of latex 
will also be longer. The incidence of dryness is comparable to conventional tapping 
system. 
REACTORRIM Stimulation Technique 
REACTORRIM is a latex stimulation technique using ethylene gas from a reactor 
bottle supplied directly into the laticiferous tissue of the rubber tree gradually and 
continuously through the MPM. This stimulation technique is combined with 1/8 
spiral short cut (1/8S) with d/3 or d/4 tapping frequency (Figures 9.22-9.24). 
278 
The button is fixed 15 cm above the tapping 
panel in the centre between two tapping 
panels 
The canister is fixed 8 cm on the right hand side 
of the border of the tapping panel 
The tapping panel is opened adjacent to the 
previous tapping panel with a 1/8 spiral tapping 
cut (10 cm) 
Figure 9.22 REACTORRIM stimulation technique 
279 
R E A C T O R R I M C O M P O N E N T S 
Button & canister bottle 
'IT Pin 
ADDITIONAL G A D G E T S 
Figure 9.23 REACTORRIM components 
280 
Fixing Procedures of REACTORRIM 
(i) 
Open a 1/8 spiral tapping cut (1/8S) on the HO tapping panel 
above panel BI-1 or BI-2. Tap a few times on the groove until 
the desired depth is achieved. The tapping utensils should 
be fixed beforehand (1.2-litre collection cup, spring, hanger, 
spout). Tapping system : 1/8ST d/3, d/4 + REACTORRIM. 
(ii) 
Fix the button 15 cm above the 1/8 spiral tapping groove 
(Do not hit too hard and ensure that the button is securely 
fixed). 
(iii) 
Fix the 'IT pin, 7.5 cm to the right of the tapping panel of 
1/8Sand 15 cm above the earlier Vi spiral base panel. 
281 
Hang the canister to the 'IT pin (Ensure that the PVC 
tubing does not get entangled). 
A completely fixed REACTORRIM set. 
Figure 9.24 Fixing procedures of REACTORRIM 
Note: The fixing of the REACTORRIM gadgets can be completed within 5 minutes/tree. The gas will be 
absorbed continuously into the bark as soon as step 3 is completed. 
Recommendation: Tapping can be done after 48 hours or 2 days after step 3. Upon regassing, tapping is to 
be carried out 24 hours after that. 
282 
Regassing REACTORRIM Canister 
Place the nozzle of the air-gun to the inlet valve. 
Press the trigger of the air-gun to fill gas into the canister. Fill 
up with gas up to a pressure of 50 p.s.i. (The hissing sound 
stops once the pressure reaches 50 p.s.i.; approximately 
in 10 seconds and the canister becomes firm and feels 
warm). 
Remove the nozzle from the inlet valve. 
(iv) 
On completion of filling gas into the canister, the valve of 
the gas tank should be closed using a spanner. 
Figure 9.25 Regassing the REACTORRIM canister 
283 
Important Points to Note (REACTORRIM): 
i. During the initial stage, the pressure in the canister must not be more than 50 
p.s.i. Avoid over-regassing into the canister. 
ii. Check the MPM, for the following : 
• The content or pressure of the gas in the canister is lower than normal. 
Change the MPM if it does not function well. 
• The canister is still firm after 2-3 months. Change the MPM if it does 
not function well. 
iii. If there is leakage of the plastic tube near the outlet valve, cut the portion away 
and refix it. 
iv. Shift the button to a new position (< 15 cm above the 1/8S tapping groove) if it 
is found to be loose or its position is in an awkward manner resulting in leakage 
of gas. 
RRIMFLOW Stimulation Technique 
fixed 15 cm 
tapping panel 
the right border 
Figure 9.26 RRIMFLOW stimulation technique 
RRIMFLOW is a latex stimulation method incorporating direct intermittent supply of 
ethylene gas into the bark of the rubber tree. This stimulation technique combines short 
cut tapping system that involves tapping panel of one-eighth circumferance (1/8S or 10 
cm length) with low intensive tapping d/3 or d/4 and direct ethylene gas supplied every 
10 days (Figures 9.26-9.28). 
284 
1. Applicator component 
PVC 
Applicator 
Cap 
One way 
gas valve 
Tubing 
2. Component to fix applicator 3. Component to refill gas 
Water sprayer 
Water reactive 
adhesive (to fix 
applicator onto 
the tree 
Adhesive (applied 
around applicator) 
Regulator Set 
High pressure 
PVC tube 
Air gun 
Gas cylinder containing 1.3 kg 
or 0.9 kg ethylene gas 
Harness 
Figure 9.27 RRIMFLOW components 
Open a tapping cut of 1/8 of the circumference (10 cm) on the 
high tapping panel (HO). Tap a few times on the groove until 
the desired depth is achieved. 
(ii) 
A * 
Clean the bark by scrubbing the area where the applicator 
is to be fixed i.e. 7.5 cm to the right of the 1/8S tapping panel 
and 15 cm above the old base tapping panel i.e. above the 
BI-2 (before this BO-2). After the bark is cleaned, spray 
water on the area to be fixed with the applicator. Tapping 
system : 1/8S d/3, d/4 + RRIMFLOW. 
285 
Apply water-reactive adhesive along the edge of the 
applicator and even it out with a clean stick. 
Place the applicator in the cleaned bark and staple it on. 
Make sure the edges of the applicator are properly sealed 
to the tree. 
Cut a suitable length of PVC tubing (usually 60 cm) and 
apply a bit of contact adhesive at one end of it that has a 
slant cut. 
Insert PVC tubing (with contact adhesive) into the applicator 
valve. 
286 
(vii) 
Insert the cap holder through the PVC tubing followed by 
plugging the one-way valve to the end of the tube. 
(viii) 
Close the one-way valve with the cap with the PVC 
tubing forming a hook. Note : Steps (i) to (viii) to be 
done on the same day. 
(ix) 
(X) 
The next day, prepare a mixture of contact adhesive (EA 
gum) and latex between ratios 99:1 and 9:5. Note : 
One tin of contact adhesive (EA gum) can be used for up 
to 400 applicators. 
Apply the contact adhesive (EA-gum) and latex mixture 
on the edge of the applicator. Ensure the edge of the 
applicator is properly sealed to the bark of the tree. 
Let the adhesive/latex mixture to cure between 24-48 
hours 
Figure 9.28 Fixing procedures of RRIMFLOW 
287 
Gassing for RRIMFLOW 
(i) 
(ii) 
(iii) 
Gas cylinder is carried using a harness. 
Remove the cap of the one-way valve with a slight turn. 
Insert the nozzle into the one-way valve. Apply a pulse 
of gas into the one-way valve by pressing and releasing 
immediately the trigger of the air gun. Replace cap of one­
way valve. One pulse is sufficient for one tree. One cylinder 
of gas is sufficient for approximately 15,000 trees. 
Figure 9.29 RRIMFLOW gassing procedures in the field 
288 
Important Points to Note (RRIMFLOW): 
i. After each installation, the first tapping is only carried out 48 hours after gassing 
into the applicator. Subsequently, tapping is done 24 hours after gassing. 
ii. Ensure that there is no leakage at the applicator. Usually it occurs between the 
applicator and the bark of the tree. 
iii. If minor damage is done to the applicator by insects or animals it can be repaired 
by sealing with masking tape and adhesives. But if the damage is beyond repair, 
then, the applicator is to be replaced with a new one. 
iv. If leakage is detected at the sides of the applicator, apply a mixture of adhesive 
and latex on it. Maintenance of the applicator has to be carried out at least 
twice a year (i.e. resealing). It is recommended that applicators be checked for 
leakage regularly, e.g. once in two months. 
v. It is advisable to detach the PVC tube from the one-way valve at the second 
tapping. This is to ensure that water does not accumulate at the applicator and 
this will also help in differentiating the gassed trees from the non-gassed trees. 
vi. During the wintering months, there is no stimulation. Tapping is reverted to the 
normal base panel until the wintering period is over. 
vii. To overcome the problem of volatile fatty acid (VFA), second collection has 
to be done so as to not to leave any residual latex in the cups or else add 
preservatives or coagulants such as ammonia or TMTD/Zno solution into the 
latex cups after tapping. 
G-FLEX Stimulation Technique 
G-FLEX which is a more user-friendly stimulation device, especially in terms of fixing 
and maintenance. It is an improved gaseous application technology combining several 
criteria from the RR and RF technology. This technology was developed to encourage 
more users, specifically the individual smallholders, to adopt gaseous stimulation. It 
was launched in 2004 by MRB. 
289 
15 cm 
Placement of G-FLEX 
container is between 
7.5 cm to the right of the 
tapping panel of 1/8S and 
15 cm above the BI-1 or 
BI-2 tapping panel. 
Figure 9.30 G-FLEX and its placement 
Sealant 
One way valve 
PVC tube Silicon paper 
Figure 9.31 Components of G-FLEX 
290 
291 
Procedures of Fixing G-Flex 
(i) 
Open a tapping cut of 1/8 of the circumference (10 cm) 
on the high tapping panel (HO). Tap a few times on the 
groove until the desired depth is achieved. 
(ii) 
Clean the bark surface of flakes and dirt and wipe the 
area where the G-Flex is to be placed (7.5 cm to the 
right of the tapping panel of 1/8 S and 15 cm above 
the BI-1 or BI-2) with a damp cloth. 
(iii) 
Remove the G-FLEX cover (silicon-coated paper). 
(iv) 
Once the bark surface has dried, place G-FLEX 
appropriately and press onto the sealant evenly. 
292 
Blow into container until it is well-expanded to 
check for leakage. 
Side view of well-expanded G-FLEX. 
Staple each corner while the container is still in 
expanded shape. 
Figure 9.33 Procedure of fixing G-FLEX 
293 
Gassing procedure for G-Flex 
(i) 
ABU 
- m Remove the one-way valve. 
(ii) 
(iii) Wt 
(iv) 
Empty the container by pressing and releasing the air slowly. 
Re-attach the one-way valve to the delivery plastic tubing. 
Fill in the gas. 
(v) 
J H B | 
Gas is filled into the container slowly until full (expanded) 
once in every 10 days. Each canister of gas is sufficient for 
gassing up to 2,000 trees. Tapping to be carried out 48 
hours after the first installation and gassing. Subsequent 
tappings could be done 24 hours after each re-gassing. 
Figure 9.34 Procedure of gassing in the field 
294 
Do-it-Yourself (D.I.Y.) Maintenance Technique of G-Flex 
(i) 
If wrongly placed or sign of gas leakage suspected or slightly 
damaged, remove G-FLEX from the tree and detach the 
sealant. {G-FLEX sealant is re-usable) 
Re-use the container (If badly damaged get a new 
container) 
Re-shape the sealant to its original form. 
(iv) 
Place the sealant back properly and re-attach the container 
on the tree 
Figure 9.35 Do-It-Yourself techniques of G-FLEX 
295 
Characteristic of G-FLEX 
User friendly 
method of fixing has been simplified due to simple gadgets used. 
Easy to manage and maintain 
the most critical aspect of maintenance is pressing the sealant before re-
gassing. 
Flexible 
G-FLEX can be used on high tapping panels combined with a short tapping 
cut and tapped on d/3 or d/4 tapping frequency. The sealant allows G-FLEX 
to be repositioned without changing the components. The formulation allows 
the sealant to accommodate the growth expansion which reduces the problem 
of gas leakage and maintenance of the components of G-FLEX. 
• Do-it-yourself (D.I.Y.) 
users can fix the G-FLEX components on their own. 
Gassing 
simplified method of gassing. 
Important Points to Note (G-Flex): 
(i) Presently, all gaseous stimulation techniques i.e. RRIMFLOW, REACTORRIM 
and G-FLEX, are recommended for application to premium rubber trees only 
(i.e. 15 years and above with both panels BO-1 and BO-2 consumed). 
(ii) The tapping system recommended is 1/8S| d/3, d/4 with upward opening of 
tapping panel (HO). The gaseous stimulation technique produces optimum 
yield when combined with the 1/8Sf d/3, d/4 tapping system. Longer cuts do 
not result in increase of yields. 
(iii) At the initial stage, the rubber tree is tapped 48 hours or 2 days after gassing is 
done. After that, the tree can be tapped 24 hours or one day after gassing. 
(iv) It is very important to make sure that there is no leakage of gas at the container 
or button as this may result in a drastic reduction in yield. 
(v) The proper installation, scheduled tapping, regular gassing and maintenance 
as recommended coupled with good agronomic practices are very important 
factors in obtaining high yields in rubber. 
296 
CONTROLLED UPWARD TAPPING 
High panels, especially on trees with straight clean stems (without branches) up to the 
height of 3 m, can provide additional areas of bark panel which is equally important in 
terms of yield. If the high panels are to be tapped downward, a ladder has to be used 
and this creates additional burden to the tapper. A bark island will also be formed, where 
eventually, as the tapping goes down, the yield gets lesser and lesser. This is because 
the latex vessels have been severed and the vessel network is being cut off. Therefore, 
the bark has to be tapped upward, using a modified tapping knife. Actually, upward 
tapping had been practised since the 1950's. Due to various problems encountered, 
the technique became unpopular and later abandoned. The upward tapping technique 
described in this chapter is the controlled upward tapping (CUT), which is an improvement 
of the old one. It is controlled in respect of the slope of the tapping cut and the bark 
consumption. 
The Tapping Knife 
The knife is a modified gouge, with V-shaped blade of 60° angle. The width of the blade 
is 1.8 cm, tapering inward of 60°. The length of the blade is about 10 cm and bent away 
from the handle at 30°. It is fitted to a wooden handle, the length of which depends on 
the height of the tapping cut (Figure 9.36). 
Figure 9.36 The controlled upward tapping (CUT) knife 
Opening of the Tapping Panel 
Controlled upward tapping can commence when tapping on panel BI-1 has been 
completed. Its first panel (HO-1) is opened at 1/8 S, 150 cm from the ground level and 
in line with panel BI-1. The angle of slope is 45° to effect a faster flow of the latex along 
297 
the cut. Four panels can be obtained from the trunk circumference (HO-1, HO-2, HO-3 
and HO-4) to be tapped up to a height of 3 m at approximately two years per panel. 
To open the first panel, a vertical cut 60 cm long is made above the lower 
panel which has just been fully tapped. A string is wrapped around the trunk and 
folded equally into four. The four-folded string is stretched across the trunk to obtain a 
quarter circumference, and the right end of the string is marked. Another vertical cut is 
made on the bark 60 cm long at this quarter circumference mark. A pre-prepared 45° 
template is placed over the trunk with its right edge in line with the right vertical cut, and 
the template is wrapped around the trunk towards the left. Using crayon or nail, a mark 
is made along the top edge of the template. A 45° slope is now marked on the trunk. 
The bark along the marked slope is tapped away. This is repeated several times until a 
2.5 cm panel is opened to fit in the blade of the controlled upward tapping knife. Then, 
an upward cut is made on the upper cut of the panel using the upward tapping knife. 
A spout, hanger and cup can now be fixed on the tree. Using the rollmarker, the bark 
to be consumed monthly can be marked for eighteen months' consumption. Ethephon 
at 5.0% is applied along the groove of the tapping cut. The tree is ready for upward 
tapping the following day (Figure 9.37). 
(a) Tree suitable for CUT (b) CUT panel succession 
Figure 9.37 CUT system for the upper panel 
298 
(a) Marking panel (b) Measuring one quarter (c) Marking the slope 
boundary lines circumference 
299 
Technique of Tapping 
To tap the tree, the tapper stands facing the tree where the upward panel is located. 
His feet are 30 cm apart and 45 cm away from the base of the tree. His left hand holds 
the upper part of the wooden handle gently, while his right hand grips the lower end 
of the handle to push the knife. Starting at the right lower corner of the tapping cut, 
the blade is pushed into the bark, slightly tilting the inner blade away from the panel 
to avoid wounding it. The cutting is continued and when it reaches half way along the 
cut, his right leg is lifted off the ground passing behind his left leg. At the same time the 
cutting is continued to reach the left hand corner of the tapping cut and his left leg is 
simultaneously moved to the left. The whole tapping cut is completed in two steps only. 
Throughout the tapping operation, both the tapper's arms must be below the shoulder 
level to prevent tiredness. The latex should be guided to flow along the cut and the 
vertical channel to avoid spillage (Figure 9.38). The depth of tapping is as usual, but the 
thickness can be slightly more than the downward tapping, and 25-30 mm per month on 
alternate daily is permissible. 
After some time, the tapping cut gets higher and higher and there can be 
difficulty in getting the latex into the cup. This can be overcome by fixing two spouts, 
connected by a tightly fixed piece of fine wire or tree lace. 
Ethephon stimulant is applied along the lace monthly. Upward tapping with a 
quarter cut does not yield well without stimulation. As stimulation is not recommended 
during the wintering months, tapping should be on panel BI-2 without stimulation. When 
panel HO-1 is completed, tapping should be changed to panel HO-2 and so forth until 
the whole trunk circumference above 150 cm is completely tapped. 
Controlled upward tapping of high panels generally gives much higher yields 
than downward tapping, at the same time doing away with the ladder climbing system. 
However, there are variations in clonal responses to yield (Table 9.9). Tapping the high 
panels also results in longer economic life of the trees. 
TABLE 9.9 CLONAL RESPONSE ON YIELD FROM CONTROLLED UPWARD TAPPING 
Response Clone 
Good (> 50%) GT1, RRIM 600, RRIM 614, RRIM 605, PR 107 and RRIM 501 
Moderate (30-50%) RRIM 623 and PB 5/51 
Poor (<30%) LCB 1350 and Tjirl 
300 
TASKING AND RETASKING 
The number of trees allocated to a tapper for tapping within a specified time, usually a 
day's work, is called a tapping task. The work of allocating the task is known as tasking, 
while retasking means reorganising or reviewing existing tasks. 
Approach to Tasking 
The size of a tapping task is based on a number of factors, namely, the planting density 
per hectare, topography of the area, size of the tree trunks and length of the tapping 
cut. Avery high task size gives higher yield to the tapper but a lower yield to the hectare 
basis. This is because the tapper takes a much longer time to complete his task and 
therefore quite a large number of trees are tapped during the late morning. A very low 
task size results in the tapper completing his task early, thus higher yield to the hectare 
basis, but lower yield to the tapper. The number of tappers required is also high, which 
can also lead to higher tapping cost (Table 9.10). 
The number of tappers required for a particular area can be calculated by the 
following formula : 
Number of Tappers _ Planting density per hectare x size of the area (ha) 
Required Frequency of tapping x task size 
Example: 
Planting density per hectare = 480 trees 
Size of the area = 100 ha 
Frequency of tapping = d/3 
Task size (per tapper) = 600 trees 
480x100 
3 x 6 0 0 
= 27 tappers 
The area (ha) covered by each tapper can also be calculated by the following 
formula: 
Area Covered = Frequency of tapping x task size 
Planting density per hectare 
301 
Example: 
Frequency of tapping 
Task size (per tapper) 
Planting density per hectare 
Area covered per tapper 
TABLE 9.10 MAPA-NUPW TAPPING TASK SIZES 
Topography 
of area 
Height of 
tapping 
Length of Years of tapping 
tapping 
cut <5 5-10 10-15 15-20 20-25 >25 
Flat and Low 1/2S 600 575 530 510 465 450 
undulating SIR 552 529 488 469 428 414 
S 480 460 424 408 372 360 
High 1/2S 390 374 345 332 302 293 
High and 
low 
1/2S or 
1/2V and 
1/2S 
- - 225 217 198 191 
1/2S or 
1/2V and S - - 201 194 177 171 
Terraced hill Low 1/2S 564 541 498 479 437 423 
S/R 519 497 459 441 402 389 
S 451 432 399 384 350 338 
High 1/2S 371 355 328 315 287 278 
High and 
low 
1/2S or 
1/2V and 
1/2S 
- - 218 210 192 185 
1/2S or 
1/2V and S - - 195 188 172 166 
Note: Where upward tapping is carried out without the use of the ladder, the task size is 90% of the normal 
task tapped downward. 
For hilly areas where the terraces are less than a metre wide, the task size must be agreed upon at the 
plantation level. For special or experimental tapping, the task size is also to be agreed upon at plantation 
level. 
d/3 
600 trees 
480 trees 
3 x 6 0 0 
480 
3.75 ha = 3.8 ha 
302 
Method of Tasking and Retasking 
Tasking can become simpler if a particular area or plantation has a point plan prepared 
during the development stage. If there is none, the whole area that is to come under 
tapping must be thoroughly studied for this purpose. There must be separate tasks for 
the flat and hilly areas. If possible, all tasks must have a road frontage to facilitate latex 
collection. For a flat area, the allocation of tasks must be according to the row, while 
for the hill slopes according to the terraces. Avoid roads, rivers, streams and swamps 
from separating tasks. They should be used as boundaries for the tasks instead. Task 
boundaries must be clearly marked with task numbers painted on the border trees. 
Retasking may be necessary from time to time. This takes place when more 
new trees come into tapping or there is a reduction in density due to losses by diseases 
or pest attacks or other physical injuries. Sometimes, a change in the tapping system 
also necessitates the existing task size to be reviewed. 
TAPPING SYSTEMS 
A tapping system refers to the manner in which a rubber tree is exploited. It consists of 
the length and type of cut, frequency of tapping and stimulation. All these are given in 
symbols. The following are a number of tapping systems and their descriptions, which 
have been in use in Malaysia. 
1/2S d/2 
Half spiral tapping cut, tapped alternate daily. This has been the most popular tapping 
system. It is suitable on most clones, except those susceptible to brown bast or tree 
dryness. The annual bark consumption for this system is 20-25 cm. Yield obtained is 
high. This system is considered optimum in terms of growth, yield, tapping cost and 
bark renewal. 
1/2S d/3 
Half spiral tapping cut, tapped third daily. This system is grouped under the low 
frequency tapping system. It is suitable for seedling materials and clones susceptible to 
brown bast, and in areas where there is shortage of tappers. Yield is about 85% of 1/2S 
d/2. The annual bark consumption is 18-25 cm. The DRC of latex obtained is slightly 
higher, while the tapping cost is 15% lower than 1/2S d/2. A tapper can tap more trees 
using this system, hence less tappers are required. Stimulation is required to level up 
its yield with 1/2S d/2. 
303 
1/2S d/4 
Half spiral tapping cut, tapped fourth daily. This system is also a low frequency tapping 
system. It consumes 15-20 cm of bark annually. The yield is lower and must be 
enhanced with stimulation. The DRC of latex is much higher. It is designed for areas 
where there is shortage of tappers, as a tapper using this system can tap 100% more 
trees compared to 1/2S d/2. Tapping cost is much lower. 
1/2S d/6 
Half spiral tapping cut, tapped sixth daily or once a week. This is an ultra low frequency 
tapping system, specially designed for the period of acute shortage of tappers. A tapper 
can handle six tapping tasks with this system. Studies have shown that there is a 
difference in yield response according to clones. The good response in yield is only 
obtained by the modified method of stimulant applications, which is the lace combined 
with the bark application. This system requires the bark to be tapped up to 3 mm per 
tapping due to the dry bark tissue during the long rest between tappings. The monthly 
bark consumption is approximately 15 millimetres. It is best to start on this system 
from commencement of tapping. However when trees have been subjected to high 
frequency tapping of d/2 to d/3, d/4 and d/6 over a period of one to two years and if the 
present cut is nearing the ground level (30 cm and below), start on a new panel when 
changing to low frequency. 
1/2S d/2 9m/12 
Half spiral tapping cut, tapped alternate daily for nine months, followed by three months 
of rest. This system is known as the periodic tapping system. Using this system, a 
tapper can handle a larger tapping area. 
1/2S d/3 9m/12 
Half spiral tapping cut, tapped third daily for nine months, followed by three months of 
rest. The number of tasks that can be handled by a tapper with this system of tapping 
304 
is higher. The three months rest to the trees in a year reduces tapper requirement by 
25%. There is also a good deal of reduction in bark consumption. Yield of PB 235 and 
PR 255 on this system is comparable to 1/2S d/3. 
Other Alternative Sys tems 
Actually there is no perfect single tapping system suitable to all rubber trees. Tapping 
systems are recommended according to clones and ground situations. The current 
tapping systems are geared towards the low frequency ones, such as d/3, d/4, d/6, 
periodic and even the Division of Labour (DOL) system where a tapper only carries 
out tapping, while collection of latex is done by other workers. This enables a tapper 
to tap up to two tasks a day, thus overcoming shortage of tappers. 
EXPLOITATION SCHEDULES 
Exploitation schedules can be defined as the systematic procedures and stages of 
harvesting the latex yield of the rubber trees, panel by panel, from the time tapping 
commences up to the completion of the tapping cycle. A full exploitation schedule 
takes around thirty years to complete, and this time period is considered as the 
economic life of the rubber tree. 
Schedule and Sys tems 
Seven exploitation schedules are suggested, six are for clones and one for clonal 
seedling materials. The first one (Table 9.11 and Figure 9.40) describes the normal 
standard exploitation schedule for buddings with a panel-changing system (Table 9.12 
and Figure 9.41) as an alternative. To reduce bark consumption in smallholdings, a third 
system (Table 9.13 and Figure 9.42) is suggested, while the panel-changing system 
(Table 9.14 and Figure 9.43) is given as an alternative. The fifth and sixth (Tables 9.15 
and 9.16 and Figure 9.44) are low frequency schedules specially designed for areas 
with acute shortage of tapping labour. Table 9.17 and Figure 9.45 is a schedule for 
exploitation of clonal seedling materials. 
305 
TABLE 9.11 EXPLOITATION SYSTEM FOR BUDDINGS (I) 
1 
Phase Tapping 
(Figure 9.39) panel 
r r r _ : . 1 
Tapping system 
All clones Period (year) 
Brown bast 
clones 
Period 
(year) 
I (a) BO-1 1/2S d/2 ET2.5%2/y 6 1/2S d/3 ET2.5% 2/y 7 
II (b) BO-2 1/2Sd/2 ET3.3%4/y 6 1/2S d/3 ET3.3% 4/y 7 
III (c) BI-1 1/2S d/2 ET5.0% 4-6/y 5 1/2S d/3 ET5.0% 4-6/y 6 
IV (d) HO-1, 1/4ST d/2 8m/12 ET5.0% 8/y 2 
1/4ST d/3 8m/12 
ET5.0% 8/y 2.5 
BI-2 1/2S d/2 4m/12 ET5.0% 1/y* 
1/2Sd/3 4m/12 
ET5.0% 1/y* 
V(e) HO-2 1/4ST d/2 8m/12 ET5.0% 8/y, 2 
1/4Sf d/3 8m/12 
ET5.0% 8/y 2.5 
BI-2 1/2S d/2 4m/12 ET5.0% 1/y* 
1/2S d/3 4m/12 
ET5.0% 1/y* 
VI (f) HO-3 1/4ST d/2 8m/12 ET5.0% 8/y, 2 
1/4ST d/3 8m/12 
ET5.0% 8/y, 2.5VI 
B1-2 1/2S d/2 4m/12 ET5.0% 1/y* 
1/2S d/3 4m/12 
ET5.0% 1/y* 
VII (g) HO-4+BI-2 1/4S| +1/2Sd/3 ET5.0% 12/y 2.5 1/4ST + 1/2S d/3 ET5.0% 12/y 3 
Total 25.5 30.5 
"Tapping system during wintering period 
Except in phase I, throughout the tapping schedule up to phase III, the use of stimulant is on staggered 
basis (1/2:1/2), phase IV onwards to all trees and on both cuts during the final phase VII. 
c d e 
| Virgin bark | | First renewed bark ^ 
Figure 9.39 Succession of tapping panels I 
306 
TABLE 9.12 EXPLOITATION SYSTEM FOR BUDDINGS (II) 
Phase Tapping Panel-changing tapping system for all Period 
(Figure 9.40) panel clones except those prone to brown bast (year) 
I (a) BO-1, BO-2 1/4S d/2 (t,t) 8m/12 ET3.3% 4/y, 8 
BO-1&BO-2 1/2S d/2 4m/12* 
II (b) BO-3, BO-4 1/4S d/2 (t,t) 8m/12 ET5.0% 4/y, 8 
BO-3&BO-4 1/2S d/2 4m/12* 
III (c) BI-1, BI-2 1/4S d/2 (t,t) 8m/12 ET5.0% 6/y, 8 
BI-1&BI-2 1/2S d/2 4m/12* 
IV (d) HO-1, 1/4ST d/2 8m/12 ET5.0% 8/y, 2 
BI-3&BI-4 1/2S d/2 4m/12 ET5.0% 1/y* 
V(e) HO-2 1/4Sf d/2 8m/12 ET5.0% 8/y, 2 
BI-3&BI-4 1/2S d/2 4m/12 ET5.0% 1/y* 
VI (f) HO-3 1/4ST d/2 8m/12 ET5.0% 8/y, 2 
BI-3&BI-4 1/2S d/2 4m/12 ET5.0% 1/y* 
vii (g) HO-4+BI-3&BI-4 1/4S| + 1/2Sd/3 ET5.0% 12/y 2.5 
Total 32.5 
•Tapping system during wintering period 
Except in phase I, throughout the tapping schedule up to phase III, the use of stimulant is on staggered 
basis (1/2:1/2), phase IV onwards to all trees and on both cuts during the final phase VII. 
| | Virgin bark First renewed bark jj^/jj Second renewed bark 
Figure 9.40 Succession of tapping panels for buddings (II) 
307 
TABLE 9.13 EXPLOITATION SYSTEM FOR BUDDINGS (III) 
Phase 
(Figure 9.41) 
Tapping 
panel 
Daily tapping system but not exceeding Period 
twenty tappings per month (year) 
I (a) BO-1 1/4S d/1 2d/3 ET2.5% 2/y 
II (b) BO-2 1/4S d/1 2d/3 ET2.5% 2/y 3 
III (c) BO-3 1/4Sd/1 2d/3 ET3.3%4/y 3 
IV (d) BO-4 1/4S d/1 2d/3 ET3.3% 4/y 3 
V(e) BI-1, BI-2 1/4S d/1 (t,t) 2d/3 8m/12 ET5.0% 6/y, 5 
BI-I&BI-2 2x1/4S d/1 2d/3 4m/12* 
VI (f) HO-I 1/4ST d/1 2d/3 8m/12 ET5.0% 8/y, 1.5 
BI-3&BI-4 2x1/4S d/1 2d/3 4m/12* 
VII (g) HO-2 1/4S| d/1 2d/3 8m/12 ET5.0% 8/y, 1.5 
BI-3&BI-4 2x1/4S d/1 2d/3 4m/12* 
VIII (h) HO-3 1/4ST d/1 2d/3 8m/12 ET5.0% 8/y, 1.5 
BI-3&BI-4 2x1/4S d/1 2d/3 4m/12* 
IX (i) HO^+BO-3&BO-4 1/4St+2x1/4S d/2 ET5.0% 12/y 2 
Total 23.5 
* Tapping system during wintering period 
Except for phase I, throughout the tapping schedule up to phase V, the use of stimulant is on a staggered 
basis (1/2:1/2), phase VI onwards to all trees and on both cuts during the final phase IX 
308 
TABLE 9.14 EXPLOITATION SYSTEM FOR BUDDINGS (IV) 
Phase 
(Figure 9.42) 
Tapping 
panel 
Panel changing tapping system daily, but 
not exceeding twenty tappings per month 
Period 
(year) 
I (a) BO-1, BO-2 
BO-1&BO-2 
1/4S d/1 (t,t) 2d/3 8m/12 ET2.5% 2/y, 
1/2S d/1 2d/3 4m/12* 
5 
II (b) BO-3, BO-4, 
BO-3&BO-4 
1/4S d/1(t,t) 2d/3 8m/12 ET3.3% 3/y, 
1/2S d/1 2d/3 4m/12* 
5 
III (c) BI-1, BI-2, 
BI-1&BI-2 
1/4S d/1 (t,t) 2d/3 8m/12 ET5.0% 4/y, 
1/2Sd/1 2d/3 4m/12* 
5 
IV (d) HO-1, 
BI-3&BI-4 
1/4S| d/1 2d/3 8m/12 ET5.0% 8/y, 
1/2S d/1 2d/3 4m/12* 
1.5 
V(e) HO-2, 
BI-3&BI-4 
1/4St d/1 2d/3 8m/12 ET5.0% 8/y, 
1/2S d/1 2d/3 4m/12* 
1.5 
VI (f) HO-3, 
BI-3&BI-4 
1/4ST d/1 2d/3 8m/12 ET5.0% 8/y, 
1/2S d/1 2d/3 4m/12* 
1.5 
VII (g) HO-4+BI-3&BI-4 1/4St+1/2S d/2 ET5.0% 12/y 2 
Total 21.5 
* Tapping system during wintering period 
Except for phase I, throughout the tapping schedule, the use of stimulant is on a staggered basis (1/2:1/2), 
phase VI onwards to all trees and on both cuts during the final phase VII 
Figure 9.42 Succession of tapping panels for buddings (IV) 
TABLE 9.15 EXPLOITATION SYSTEM FOR BUDDINGS (V) 
Phase 
(Figure 9.43) 
Tapping 
panel 
Ultra-low frequency tapping 
system Period (year) 
I (a) BO-1 1/2S d/6 ET1.5-2.0% 12/y 8-10 
II (b) BO-2 1/2S d/6 ET2.0-2.5% 12/y 8-10 
III (c) BI-1 1/2S d/6 ET5.0% 12/y 6-8 
IV (d) BI-2 1/2S d/6 ET5.0% 12/y 6-8 
Total 28-36 
Ethepon stimulant application must be by the modified method of lace or groove plus 0.64 cm of scraped 
bark below the tapping cut 
TABLE 9.16 EXPLOITATION SYSTEM FOR BUDDINGS (VI) 
Phase 
(Figure 9.43) 
Tapping 
panel Periodic tapping system 
Period 
(year) 
I (a) BO-1 1/2S d/3 9m/12 ET1.5-2.0% 9/y 7-8 
II (b) BO-2 1/2S d/3 9m/12 ET2.0-2.5% 9/y 7-8 
III (c) BI-1 1/2S d/3 9m/12ET5.0%9/y 6-7 
IV (d) BI-2 1/2S d/3 9m/12ET5.0%9/y 6-7 
Total 26-30 
Ethepon stimulant application must be by the modified method of lace or groove plus 0.64 cm of scraped bark 
below the tapping cut 
Figure 9.43 Succession of tapping panels for buddings V and VI 
310 
TABLE 9.17 EXPLOITATION SYSTEM FOR CLONAL SEEDLINGS 
Phase 
(Figure 9.44) Tapping panel Tapping system Period (year) 
I (a) BO-1 1/2S d/3 ET3.3% 2/y 4 
II (b) BO-2 1/2S d/3 ET3.3% 4/y, 6 
III (c) BO-3 & BI-1 1/2S d/3 ET5.0% 4-6y 6 
IV (d) HO-1, 1/2Sf d/3 8m/12 ET5.0% 8/y 3 
BI-2 1/2S d/3 4m/12 ET5.0% 1/y* 
V(e) HO-2, 1/2ST d/3 8m/12 ET5.0% 8/y, 3 
BI-2 1/2 d/3 4m/12ET5.0%1/y* 
Total 22 
"Tapping system during wintering period 
Figure 9.44 Succession of tapping panels for clonal seedings 
It can be noted from the fifth and sixth exploitation schedules (Tables 9.15 and 
9.16) that only the lower panels (BO and BI) are exploited. As such larger volumes of 
good quality timber can be recovered for downstream usage during replanting later on. 
311 
From experiments carried out, there was evidence showing that different 
clones respond differently with regards to tapping systems and stimulation. The above 
recommendations are therefore general in nature and can be modified accordingly 
depending on the situation. 
If the trees have been stimulated from commencement of tapping, there may 
be marked drop in yield when the tapping cuts approach the base of the trees, unless 
the trees had been deeply planted during transplanting (deep planting technique). If 
this happens the panels should be changed immediately. 
TAPPING MANAGEMENT 
Besides the systematic development of the plantation, the usage of high quality 
planting materials and good plantation maintenance, the management and 
maintenance of the tapping operation are also important in determining the maximum 
yield return of the crop. The functions of the tapping management, therefore, can be 
considered as ensuring that the following are strictly implemented. 
Attendance 
The first thing that is required in a tapping operation is to ascertain whether tapping 
for the day can be carried out. If this is not possible, then recovery tapping must be 
arranged, either later in the day or tapping on a rest day. This is important to achieve 
maximum yield as well as to maintain the minimum number of tapping days in a month 
or year. 
Attendance of tappers should be duly recorded and for those who are absent, 
replacement must be made to ensure that no tasks which have been scheduled to be 
tapped for the day are left untapped. It is also important to see that the tappers reach 
their tasks quickly and safely. 
Tapping Equipment and Utensils 
The supply of good equipment and utensils should also be ensured. This includes 
tapping knives, cups, spouts, buckets and others. They should be replaced immediately 
when found defective. The tapping knife is the most important item in effecting good 
tapping. Suitable ones should be supplied and must always be ensured that they are 
reasonably sharp. 
312 
Tapping Technique 
Tapping should commence as early in the morning as possible. Scrap rubber such as 
the tree and spout laces and cuplumps are removed before tapping is done. The full 
length of the tapping cut within the panel boundary must be tapped away. The depth 
of tapping should be up to the maximum. However, contact with the cambium must be 
avoided. The thickness of tapping is kept to the minimum. It must be ensured that the 
latex actually flows into the cup. All tappable trees in the task are tapped. 
Collection 
Latex is only collected when it stops dripping, unless late dripping occurs. It is 
completely removed from the cup into the collecting bucket. Latex is collected from 
all trees tapped in the task for the day. Scrap rubber is also collected and placed in 
separate utensils. 
Latex Stability and General Cleanliness 
The stability of the latex must be maintained until it reaches the collecting station 
or factory. This means that the latex must be retained in its liquid condition. A high 
standard of cleanliness must be maintained to achieve this. This includes cleanliness 
of all equipment and utensils used and at the same time keeping the latex covered 
during transportation. Latex preservative must be used, if necessary. The latex cup 
should be placed in the inverted position when the tree is not tapped. All equipment 
returned to the store after tapping must first be cleaned. 
Maintenance of Tapped Trees 
All forms of injuries to the trees must be avoided. The slope of the tapping cut of either 
20°, 30° or 45° must always be maintained. Its direction must always be at high left 
to low right. Steps to control bark consumption must also be carried out. The front 
and back vertical channels marking the panel boundary must be regularly serviced 
(deepened). If the trees are under stimulation programme, the application of stimulant 
must be properly carried out when due. The position of the latex cups and spouts 
must always be at suitable distance. The trunks of trees must be cleaned of mosses 
and scrap rubber from time to time. Trees reaching tappable size must be opened for 
tapping. Retasking must be implemented when the number of tapped trees in the task 
has either increased or decreased markedly. All defects and malfunction occurring to 
the trees or in the field that affect the tapping function must be duly reported. 
313 
Tappers ' Welfare 
It is also necessary to keep a complete record of the tappers' daily crops, especially 
if it is going to be used as the basis for payment of their wages. All tappers must 
be promptly and accurately paid for work done when due. Incentives must also be 
considered for those showing exemplary work. Tappers must be thoroughly trained; 
this includes in-service training when there are changes in the tapping systems or 
methods. No deviation of any form must be allowed to take place. 
Task Census 
The above information can be used in carrying out monitoring exercises when there 
is a drop in the yield of a plantation. Such an exercise is known as the task census. 
Each tree in the reported low yielding task is inspected and remarks are entered in 
the questionnaire. The results are then summarised and compared with the standard 
performance of a task. The information obtained may assist the management to 
improve the task concerned. This trouble-shooting exercise has in the past proved to 
be very useful to the management of plantations and substantial yield increases have 
been reported as a result of such census. 
314 
CHAPTER 10 
NATURAL RUBBER PROCESSING 
PROCESSING FIELD LATEX AND COAGULA 
Processing of natural rubber itself covers quite a large part of rubber technology. This is 
because several processes can be made possible from the raw materials of the rubber 
tree, namely, latex and field coagula. Approximately 80% of the rubber tree yield is in 
the form of latex, while the other 20% is the lower grade field coagula, which includes 
cuplumps, tree laces and other forms of solid rubber. The field coagula are also known 
as scrap rubber. This chapter deals briefly with what can be done with the field latex 
and the field coagula. 
Field Latex 
Field latex, which is in liquid form, can be concentrated on coagulated. There are certain 
rubber products which require latex as their raw material. They are grouped under 
latex products, which consume some 20% of the world's rubber production. Thus, to 
facilitate transportation and storage, field latex which contains considerable amount of 
water must be concentrated, and this alone is a major process. However, most rubber 
products require solid rubber as their raw material. This necessitates the coagulation 
of field latex. Coagulation process is also necessary for the production of conventional 
sheet rubber, such as Unsmoked Sheet (USS), Ribbed Smoked Sheet (RSS), Air-dried 
Sheet (ADS) and crepes and the modern block Standard Malaysian Rubber (SMR). 
The powdered rubber process also comes under this category. 
Field Coagula 
Processing field coagula is simpler as the raw materials are already in solid form. It is 
mainly used for the production of lower grade crepe and block rubbers because of their 
higher dirt content compared to latex. 
Superior Processing Rubbers 
There are certain rubber products of fine quality which require rubber of special quality and 
properties. These come under the special or superior process which produces special 
rubbers, such as Deproteinised NR (DPNR), Epoxidised NR (ENR), Oil-Extended NR 
(OENR), Methyl-methacrylate Grafted Rubber (MGR) and Thermoplastic NR (TPNR). 
315 
A summary of the various processes of natural rubber is illustrated in Figure 10.1 below: 
Latex (± 80%) Field coagula (± 20%) 
Concentration Coagulation 
I I 
Evaporation Creaming Centrifugation 
I 
Latex Glove, Foam Rubber 
Condom, ENR, DPNR, MGR 
Skim rubber Skim latex • 
Acid coagulation Heat coagulation 
Sheet Block 
I I 
Crumbs Comminuted 
1 
General uses 
Crepe 
General uses 
Blending — SMR GP General uses 
Block rubber Powdered 
Rubber 
Sheet rubber 
Crumb Comminuted 
L 
r 
General Special 
uses uses 
Crepe ADS SPADS SPRSS USS 
I I I I RSS 
Special uses 
General uses 
TPNR, SMRCV 
Figure 10.1 Natural rubber processing 
CLEANLINESS IN PROCESSING 
Cleanliness is an important factor in the processing of natural rubber, as it determines 
the quality of the rubber produced. The value of rubber depends very much on its 
quality, and a high quality rubber gives a high return of income to the planter, as the 
316 
price paid by the consumer is according to its quality. Besides, good quality rubber has 
a much wider range of uses. At the consumers' end, it eliminates processing difficulties 
usually encountered with low quality rubber. Hence, high quality rubber is more readily 
marketable. There is also a premium in terms of price for good quality latex. 
Everyone involved in the handling of latex, starting from the time it oozes out of 
the bark of the tree until it is finally processed, must be made to realise the importance 
of cleanliness. The latex that comes out of the bark of the rubber tree is clean naturally. 
It is contaminated and polluted by the people who handle it. Therefore, cleanliness 
should be practical in all three stages, namely, in the field, in the processing factory and 
during post-processing operation. 
Field/Tapping Cleanliness 
Cleanliness starts in the field. The most important thing to remember here is to maintain 
the liquid condition of the latex until it reaches the processing factory. This can be 
achieved by preventing precoagulation of the latex. Latex becomes precoagulated when 
it is contaminated with dirt. Therefore, it is necessary to ensure that only clean tapping 
equipment and collecting utensils, such as cups, spouts, buckets and churns are used. 
All scrap rubbers removed from the field must be collected in a separate container. Latex 
collected must not be exposed and must be brought to the collecting centre or factory 
immediately. Latex preservatives must be used to prevent precoagulation, if necessary. 
Collecting centres must be kept clean and the work of weighing and transferring 
latex must be done with cleanliness in mind. There must be sufficient supply of clean 
water at the centre for necessary washings to be carried out. 
Factory/Processing Cleanliness 
General cleanliness must be maintained at the factory buildings and the surroundings. 
All equipment in the factory must be kept clean. There must be a sufficient supply of 
clean water for use at any time when the factory is in operation. The latex must first be 
strained to remove any dirt in it. A suitable strainer of twenty five mesh per centimetre 
made of monel-metal gauze should be used. The use of pure copper strainers should 
be avoided as this may contaminate the latex. 
Post-processing Cleanliness 
Rubber that has been processed must be washed clean and allowed to drip under 
shade in a clean place. Sheet rubber, such as USS, ADS and crepe must be hung 
317 
individually for at least four hours before putting them in the drying chamber. Rubber 
must always be stored in a clean, dry and well-ventilated area. As for latex concentrate, 
it must be kept in covered drums or closed tanks. 
PRESERVATION OF LATEX 
Latex from all types of rubber trees naturally self-coagulates after it oozes out of the bark. 
The only difference is the time it takes to coagulate. This difference depends on the 
type of clone, the stability of the latex and the condition of the environment. Latex that 
is unstable not only creates difficulties in handling, but also in processing. Sometimes, 
latex is required to be kept for a longer period. Thus, preservation is necessary. 
Single Preservative System 
Chemicals can be used to delay the coagulation of latex. Some examples are sodium 
sulphite, ammonia and formalin. Sodium sulphite and formalin are not very effective in 
preserving latex for long periods, while ammonia at a higher concentration can preserve 
latex for a much longer period. 
Sodium sulphite. Sodium sulphite is a white powder and marketed at 90-98% 
concentration. Before it is mixed with the latex, a stock solution of 3% is prepared by 
diluting 100 g sodium sulphite in 3 litres of water. For every 5 litres of latex, 75 ml of the 
stock solution is added. This chemical is only effective for a few hours. Excessive use 
of this chemical can cause defects in RSS and at the same time delays its drying. It is 
most suitable for latex that is to be processed into pale and sole crepes, but not block 
rubber. Sodium sulphite must be stored in airtight container in a cool place. 
Ammonia. Ammonia is marketed as gas as well as clear liquid of 30% 
concentration. A stock solution of 1% is prepared by diluting 1 kg ammonia gas in 
100 litres water or 160 ml ammonia liquid in 5 litres of water. For every 100 litres of 
latex, 100 ml of the stock solution is added. Ammonia liquid is very volatile; it must 
therefore, be kept in an airtight container. This also applies to ammonia gas which can 
escape easily. An unopened drum of ammonia liquid must first be placed inverted under 
water overnight, for use the next day. But the lid must be opened slowly to release the 
compressed air inside it. Concentrated ammonia is toxic to the skin. Therefore, parts 
of the body that come into contact with ammonia should be washed immediately. For 
safety, always use a face mask when handling ammonia. 
318 
Formalin. Formalin is available commercially in liquid form of 38-40% 
concentration. A 1% "stock solution is prepared by diluting 50 ml of formalin in 2 litres 
of water. For every 5 litres of latex, 100 ml of the stock solution is added. Formalin is 
most suitable in preventing precoagulation of latex caused by bacterial activity in the 
field. But, it is not suitable for latex in the production of block rubber. Formalin which 
has been kept for a long time can slowly oxidise and become an acid. But it can be 
neutralised by adding calcium carbonate or sodium sulphite. 
Composite Preservative System 
Normally, field latex has to be transported over some distance to central processing 
factories due to the location of the plantation and therefore time is taken before delivery 
is made. This gives rise to the problem of volatile fatty acid (VFA) formation in latex 
and causes processing difficulties. Although ammonia at very high concentration can 
overcome this problem, it is rather costly. A composite preservative system is therefore 
introduced. It is more effective and cheaper compared to using ammonia alone. 
HNS-Ammonia. This preservative system consists of two chemicals, hydroxylamine 
neutral sulphate and ammonia. It is most suitable for latex to be processed into block 
rubber of SMR CV and LV grades. Table 10.1 gives the chemicals to be used while 
Table 10.2, the preparation of the stock solution. 
TABLE 10.1 HNS-AMMONIA PRESERVATIVE SYSTEM 
Preservatives of DRC weight (%) Period of preservation (hours) 
HNS Ammonia Estate latex Smallholding latex 
0.15 0.03 11 5 
0.15 0.05 11-19 5-11 
0.15 0.07 19-30 11-20 
Boric acid-Ammonia. This preservative system is also made up of two chemicals, boric 
acid and ammonia. It is most suitable for use on latex that is to be processed into block 
rubber of SMR L grade. The chemicals and the preparation of the stock solution are 
given in Tables 10.3 and 70.4. 
319 
TABLE 10.2 HNS-AMMONIA STOCK SOLUTION 
DRC of 
latex (%) 
A B C 
NH3 HNS SS NH3 NHS SS NH3 HNS SS 
(kg*) (kg)* (litre) (kg*) (kg)* (litre) (kg*) (kg)* (litre) 
27 3.1 4.05 1.0 5.26 4.05 1.0 5.26 2.89 1.4 
28 3.1 4.20 1.0 5.26 4.20 1.0 5.26 3.00 1.4 
29 3.1 4.35 1.0 5.26 4.35 1.0 5.26 3.11 1.4 
30 3.1 4.50 1.0 5.26 4.50 1.0 5.26 3.22 1.4 
31 3.1 4.65 1.0 5.26 4.65 1.0 5.26 3.32 1.4 
32 3.1 4.80 1.0 5.26 4.80 1.0 5.26 3.43 1.4 
33 3.1 4.95 1.0 5.26 4.95 1.0 5.26 3.53 1.4 
34 3.1 5.10 1.0 5.26 5.10 1.0 5.26 3.64 1.4 
35 3.1 5.25 1.0 5.26 5.25 1.0 5.26 3.75 1.4 
36 3.1 5.40 1.0 5.26 5.40 1.0 5.26 3.86 1.4 
37 3.1 5.55 1.0 5.26 5.55 1.0 5.26 3.96 1.4 
SS = stock solution; NH3 = ammonia; HNS = hydroxylamine neutral sulphate 
* The weight of NH3 and HNS for 100-litre stock solution 
# Volume of stock solution to be added per 100 litres of latex 
TABLE 10.3 BORIC ACID-AMMONIA PRESERVATIVE SYSTEM 
Preservatives of DRC weight (%) Period of preservation (hours) 
Boric acid Ammonia Estate latex Smallholding latex 
0.2 0.03 16 11-15 
0.3 0.07 32-60 29-40 
0.5 0.03 34-44 20-27 
TABLE 10.4 BORIC ACID-AMMONIA STOCK SOLUTION 
System 
For 100-litre stock solution For 100 litres of latex 
Ammonia (kg) Boric acid (kg) Stock solution (litre) 
A 1.5 10 2.0 
B 3.5 15 2.0 
C 1.2 20 2.5 
320 
TMTD-ZnO-Ammonia. This preservative system consists of three chemicals, 0.025% 
tetramethyl-thiuram disulphide (TMTD) and zinc oxide (ZnO) in the ratio of 1:1 and 0.4% 
ammonia (Table 10.5). The percentage of the chemicals is based on the weight of the latex. 
This preservative system is suitable for field latex which is intended for latex concentrate 
production. A10% stock solution of ammonia is prepared and then mixed into the latex. 
This is followed by the TMTD-ZnO stock solution preparation by dispersion (Table 10.6). 
Mixing is done in a suitable plastic or stainless steel container (not aluminium) using 
an electric stirrer rotating at 500 rpm for ten minutes. For every 45.5 litres of the stock 
solution 45.5 litres of latex is added to form a masterbatch which can then be mixed with 
every 10,000 kg of latex that is to be preserved. 
TABLE 10.5 TMTD- ZnO-AMMONIA PRESERVATIVE SYSTEM 
Preservative (% on latex weight) Period of preservation(day) 
TMTD ZnO Lauric acid Ammonia 
2.0 
0.013 0.013 0.05 0.2 
TABLE 10.6 TMTD-ZnO-AMMONIA STOCK SOLUTION 
Material Part by weight* 
Water 75.000 
Sodium hydroxide 0.013 
TMTD 12.500 
Dispersing agent (e.g. Vultamol) 0.025 
ZnO 12.500 
* The resultant solids content is 25% 
In the preservation of field latex, it is of utmost importance to arrest the formation 
of VFA. Thus, preservatives must be added to the latex as early as possible. The 
rate of chemicals recommended earlier should serve as a guide. The user can make 
modification according to local conditions. 
321 
DRY RUBBER CONTENT IN LATEX 
Latex can be considered as a biological product of complex structure. A large part of it 
is water. Other substances that make up latex are shown in Table 10.7. 
Dry rubber content or DRC is referred only to the rubber particles found in 
latex. The DRC varies according to season, climate, soil condition, clone, age of trees, 
tapping system (length of cut and frequency of tapping), stimulation and other influences. 
Usually, the DRC of latex is within the range of 20-45% and 35% can be taken as an 
average. 
TABLE 10.7 COMPOSITION OF LATEX 
Content Percentage 
Total solids 20-48 
Rubber particles 20-45 
Proteinous substances 1.5 
Resinous substances 2.0 
Carbohydrates 1.0 
Inorganic materials 0.5 
Objectives of DRC Determination 
There are several reasons for determining DRC in latex. It is mainly used as a guide in: 
• Latex trading 
• Standardisation of latex for RSS and Block Rubber production 
• Payment of tappers' wages 
• Management of latex factories 
• Calculation of chemicals required for the processing of latex 
• Finding out the yield of an area 
Methods of DRC Determination 
There are no less than eight methods to determine the DRC of latex, from the least 
to the most accurate. However, in this book, only three are discussed, namely the 
standard laboratory method, the dipper method (previously known as the Chee method) 
and the hydrometer metrolac method. Brief descriptions of these are given below: 
322 
Standard laboratory method. Strain the latex the DRC of which is to be 
determined. Weigh the latex in kilogrammes. Stir the latex, and take about 45 ml of 
the latex into a conical flask. Weigh out 20 g of the latex into a clean dish for use as 
sample. Add slowly 150 ml of 0.5% acetic acid into the dish, at the same time rotating 
it gently. Place the dish over a steam bath until the latex sample coagulates with a 
clear serum formed over it. Remove the coagulum and press roll into a thin biscuit 
of 2 mm thickness. Dry the biscuit in an oven at 70 °C for sixteen hours. Cool the 
biscuit in a dessicator for a few minutes. Weigh the biscuit in grammes. Carry out the 
determination in duplicate. Duplicate results must check to within 0.2%. The formula 
for the calculation of the DRC is as follows: 
DRC = Weight of biscuit x 
Weight of latex sample 
DRC percentage in latex 
Weight of biscuit x Weight of whole latex 
100 
Example: 
Weight of flask + latex 
Weight of flask 
Weight of latex 
Weight of biscuit 
DRC percentage of latex 
First sample 
65.632 g 
44.873 g 
20.759 g 
6.572 g 
DRC weight of whole latex 
Second sample 
44.873 g 
23.410 g 
21.463 g 
6.768 g 
0
6
0
5 J 2 x 100 
20.759 
6- 768
 x 100 
21.463 
= 31.659% 31.533% 
Average DRC of latex = (31.659+ 31.533)/2 
= 31.60% 
Assume that weight of whole latex = 50 kg 
DRC weight of whole latex = 31 .60x50 
100 
= 15.80 kg 
This is the most accurate method of determining the DRC of latex with a total error of 
only 0.048. But it a slow method and requires high capital cost and trained personnel 
to perform the test (Figure 10.2). 
323 
Figure 10.2 Apparatus for the determination of DRC of latex by the laboratory method 
The Dipper (Chee) method. Strain the latex, the DRC of which is to be 
determined. Weigh the latex in kilogrammes. Stir the latex well, and using a special 
dipper take away 50 ml of the latex into a clean dish for use as sample. Rinse the 
dipper with some clean water and add the washing to the latex sample. Coagulate 
the latex sample with 25 ml of 1% formic acid. When a clear serum is formed, remove 
the coagulum and wash it carefully. Press roll the coagulum into a thin biscuit of 2 mm 
thickness. Dry the biscuit in an oven at 70 °C for sixteen hours. Weigh the biscuit in 
grammes. The formula for calculating the DRC is as follows: 
Weight of biscuit x 100 = DRC percentage in latex 
Weight of latex sample 
Weight of biscuit x weight of whole latex
 =
 QRC weight of whole latex 
100 
Example : 
Weight of whole latex 
Weight of latex sample 
Weight of biscuit 
35 kg 
50 g 
15g 
DRC percentage of latex 15 x 100 50 
30% 
DRC weight of whole latex 3 0 x 3 5 100 10.5 kg 
324 
This method is less accurate with a total error of 0.306. The capital cost is lower, but it 
is still a slow method (Figure 10.3). 
Figure 10.3 Apparatus for the determination of DRC of latex by the dipper or "chee" method 
Figure 10.4 Apparatus for the determination of DRC of latex by the hydrometer metrolac method 
325 
Hydrometer method. Strain the latex, the DRC of which is to be determined. 
Measure the latex in litres or weigh it in kilogrammes and then convert it to litres, based 
on 1 kg per litre. Stir the latex well. Using a long-handled dipper, and dipping it right down 
the latex, take away one measure of latex and pour it into a suitable container. Add two 
measures of clean water and mix them thoroughly by pouring from one measure into 
another several times. Transfer the latex into a cylinder until it overflows. Remove the 
froth formed on the surface of the latex by blowing it off. Dip the hydrometer metrolac 
slowly inside the latex and allow it to rest. Note the reading on the metrolac stem at 
the meniscus. Confirm this reading by slightly pushing in the metrolac in the latex and 
allowing it to rest again (Figure 10.4). The formula for calculating the DRC is as follows: 
Metrolac reading x 3 x volume of whole latex = DRC weight of whole latex 
DRC weiqht of whole latex
 x 1 0 0 = D R C percentage in latex 
Weight of whole latex a 
Example: 
Volume of whole latex = 100 litres 
Dilution = 1:2 = 3 parts 
Metrolac reading = 105 
DRC weight of whole latex = 105 x 3 x 100 
DRC percentage of latex 
31 ,500g 
31.5 kg 
3 1 5 x 1 0 0
 = 3 1 5 o / o 
100 
This method is very fast and the capital cost is very low. But it is less accurate 
with a total error of 4.053. This method is not recommended for latex trading purposes. 
The metrolac reading too can be influenced in several ways. There were cases of latex 
being adulterated to enhance the metrolac readings. Table 10.8 gives a summary of 
the effect of adulterants and external treatments of field latex determined by its metrolac 
method. 
Choice of Method 
The choice of method to determine the DRC of latex depends on the conditions and the 
facilities available at a particular location or situation and for the purpose it is intended. 
However, in the course of latex trading, in which fairness is very important, the most 
accurate method must be used. 
326 
TABLE 10.8 EFFECT OF SOME ADULTERANTS AND EXTERNAL 
TREATMENTS OF FIELD LATEX ON METROLAC DRC 
Adulterant Effect 
Wheat flour 
Significant depression of DRC 
Soap powder 
Tapioca starch 
Common salt 
Sodium sulphite 
Lime 
Formalin 
Very slight depression of DRC 
Fern juice 
Coconut water 
Pineapple leaf juice 
Alum 
Cup lump serum 
Pineapple juice 
Coconut milk 
No effect 
Rambutan leaf extract 
Calcium carbide 
Formic acid 
Aeration 
Ammonia solution 
Very slight elevation of DRC Boiling water 
Heat 
MICROWAVE RAPID METHOD FOR DETERMINING DRY RUBBER CONTENT OF 
CUPLUMPS 
The microwave rapid method for determination of DRC of cuplumps is developed to 
enable a quantitative analysis of DRC in the fields and at rubber processing factories. 
The method is simple, low cost and easy to operate which will provide reliable 
estimation of cuplump DRC to complement the existing standard method that can 
only be conducted in the laboratory. The development of microwave rapid method 
will make raw rubber trading particularly at the farm gate level more transparent and 
less susceptible to DRC manipulations particular during recent trend of high rubber 
327 
price. The method has been optimised by considering main factors influencing the 
determination of DRC including sample size, contamination by foreign materials, age 
and form of cuplumps. Laboratory and field trials of the method showed that the 
accuracy of DRC determination could be achieved within ± 2% accuracy compared 
to the standard laboratory method. The method has also been extended for DRC 
determination of creped cuplumps for factory applications which yielded high accuracy 
within a test period of less than 1 hour. 
Presently, the determination of DRC of cuplumps is mainly done qualitatively through 
visual observations by rubber dealers. The rubber content of a cuplump is measured 
based on DRC which varies from 45% to 75% depending on its age and dryness. This 
method is adopted since the standard method for determining DRC is only suitable to 
be conducted in the laboratory. The standard method requires a significant equipment 
investment and an average period of 2 to 3 days to be completed. The procedure 
for DRC determination in the laboratory based on the standard method begins with a 
cleaning stage of cuplumps using a creper equipped with a high pressure water spray. 
Cuplumps are simultaneously processed into a thin rubber sheet to facilitate drying 
process of the rubber in an oven. The DRC of cuplump is obtained by calculating the 
percentage of dry weight over the initial wet weight of the cuplump. 
Development of a rapid method for DRC determination of cuplump is to improve and to 
address problems of DRC determination. In principle, the rapid method incorporates 
a rapid rubber drying technique based on microwave technology. The rapid method is 
simple, low cost, fast, and can be readily conducted outside laboratory (Figure 10.5). 
Figure 10.5 Field trial using the rapid method at a rubber dealer premise 
328 
The procedure begins by cutting a cuplump into four equal portions and subsequently 
drying the samples using a suitable microwave oven for a specified time period 
(Figures 10.6-10.9). The drying period depends on size and weight of the cuplump 
samples. For example, microwave oven with a power output of 600 W is capable of 
drying 1000 g of rubber uniformly in less than 60 minutes. 
Figure 10.9 Uniformly dried cuplump samples to 
confirm complete drying 
329 
Microwave Rapid Method for Creped Cuplumps 
The microwave rapid method was further developed for creped cuplumps as a means 
to improve the current method for DRC determination of cuplumps at rubber factories. 
A common method to determine DRC of cuplumps by rubber processors is to obtain 
30 kg of random (grab) samples from every shipment of cuplumps. The samples are 
then cleaned and processed in creped form and dried in commercial dryer to enable 
determination of DRC. This method requires a period of 5 to 8 hours for completion. 
The microwave rapid method was extended to creped rubber by replacing the drying of 
samples in a commercial dryer with microwave drying; thus allowing the period of the 
DRC determination to be reduced to less than 1 hour. As creped rubber represents a 
homogeneous form of cuplumps, a sample creped cuplumps of with a minimum weight 
of 400 g was obtained to represent the cuplump samples to be dried using microwave 
(Figure 10.10) 
Figure 10.10 Preparation of creped cuplumps for microwave rapid method and 
creped cuplumps after drying 
The microwave rapid method rapid was able to provide a very accurate determination 
of DRC in comparison of the DRC obtained using the common dryer method. Also, 
the microwave rapid method could be used effectively for creped cuplumps as an 
improvement of the current method used at rubber factories. 
330 
National Guideline on Determination of Dry Rubber Content of Cuplumps 
Trading of cuplumps between rubber dealers and smallholders normally occurred 
in remote places around the country involving small quantities of cuplumps which 
weigh less than 50 kg per transaction. The price of the cuplumps is determined 
purely based on its dry rubber content (DRC) commonly through visual observation 
by rubber dealers and factories. This practice of determining DRC through visual 
observation combined with other price cut mechanisms imposed by rubber buyers 
has led to dissatisfaction among smallholders during rubber trading (Figure 10.11a 
and Figure 10.11b). Since there is no standard method available in the industry for 
farmgate determination of cup lump DRC, it has indirectly discouraged smallholders 
from producing good quality cuplumps as a consequence of their dissatisfaction 
during rubber trading. 
Figure 10.11(b) DRC determination 
through price cut mechanisms 
The guideline was developed with the main objectives to disseminate information 
on DRC of cuplumps produced by smallholders in Peninsular Malaysia and to 
stress the importance of producing high quality cuplumps to achieve high DRC 
values. The guideline provides an average DRC as functions of storage period 
and physical characteristics of the cuplumps. This guideline is suitable to be used 
as a guideline in the trading activities of cuplumps involving rubber dealers and 
smallholders to improve transparency of rubber transactions. The target groups for 
the usage of this guideline are smallholders, rubber dealers and also the rubber 
processing factories (Figure10.12). 
331 
Figure 10.12 Usage of guideline in rubber plantation 
The sampling was carried out throughout Peninsular Malaysia and covered all 
three seasonal variations in rubber growth period {Figure 10.13).The factors that 
influencing the dry rubber content determination were the drying period, size of the 
cuplump that been produced, impurities in cuplumps, multi layered cuplumps from a 
few tapping session, coagulum from rain contaminated latex and storing area under 
shade/without shade (Figure 10.14 and Figure 10.15). 
Figure 10.13 Sampling areas for national guideline on determination of dry 
rubber content of cuplumps throughout Peninsular Malaysia. 
332 
Day 8 
Day 12 
Figure 10.14 Examples of good quality cuplumps 
333 
Figure 10.15 Examples of low quality cuplumps 
All in all, this guideline will increase revenue and socio economic status of 
smallholders as main rubber producer and improve rubber transaction and 
transparency of DRC determination based on accurate scientific method. In 
addition, the guideline will encourage production of quality raw material to ensure 
Malaysian rubber industry remains productive, superior and competitive. 
PRODUCTION OF USS 
USS is one of the many forms of rubber processed from latex. Considered a 
conventional process, some 6.2% of Malaysia rubber is presented in this form. 
Most of the USS produced come from the smallholdings sector, where the latex is 
processed in small quantities individually or in groups at government sponsored 
processing centres. On the other hand, bulk production of USS is carried out in 
large plantations or estates and other centralised processing agencies, in which 
large volumes of latex are dealt with. Whatever it is, the most important thing to 
remember in USS production is cleanliness, from the field right up to the end of the 
production line. 
334 
Bulk USS Production 
Stages in bulk USS production normally carried out in a central processing factory are 
described below: 
Bulking and standardisation. First of all, make sure that the factory building and 
all its equipment are in clean condition. There must be sufficient amount of clean water 
available at all times. When field latex arrives at the factory, it is transferred into the 
bulking tank to obtain uniformity of the latex as well as the finished product. The DRC 
of the latex is estimated for standardisation purpose. Latex is normally standardised 
to 12.5, 15 or 20% DRC, depending on the practice of each factory. This is achieved 
by diluting the field latex with sufficient volume of clean water, which can be calculated 
according to the following formula: 
Volume of _ Volume of field latex x DRC% . . .
 r „ . . . . 
water required " DRC % to be standardised " Volume of field latex 
Example: 
Volume of field latex = 2, 000 litres 
Its DRC = 35% 
DRC to be standardized = 15% 
_ 2,000 x 35 - 2 , 0 0 0 = 2,667 litres 
15 
After the addition of correct volume of water, a few minutes rest is allowed for 
the impurities to settle. 
Coagulation and sheeting (milling). The standardised latex is then transferred 
into the coagulating tank. The latex is made to pass through sixteen to twenty four 
mesh per centimetre monel-metal gauze strainer to separate dirt and any other foreign 
particles that may be present in it. The coagulating tank comes in various sizes, 
accommodating between 900 and 1,000 litres of latex (Table 10.9). The number of 
tanks required in a factory depends on the volume of latex to be processed. 
Latex is coagulated by formic acid at phi 4.5-4.8. Table 10.10 gives the 
approximate quantity of acid and water to be added to coagulate 500 litres of diluted 
latex. The exact amount can be calculated by titration and confirmed by the pH paper. 
The latex should be well stirred, and all froth removed. The required amount of diluted 
acid is poured into the coagulation tank and thoroughly stirred with the latex. The 
partition sheets are then placed in position and the tanks covered. 
335 
TABLE 10.9 DILUTION OF FORMIC ACID 
Acid-water 12.5% DRC 15% DRC 20% DRC 
Acid 220 ml 250 ml 344 ml 
Water 20 litres 23 litres 30 litres 
The latex is considered coagulated when a clear serum is seen over the coagulum. 
The tank is then flooded with clean water to submerge the coagulum, thus preventing 
oxidation. Milling (sheeting) is normally carried out the following day, when the coagula 
are firm enough for easy handling. The partition sheets are removed, and the coagulum 
slabs taken out and allowed to pass through three to four pairs of motorised smooth-
surfaced roller presses, popularly known as the sheeting battery, to reduce the thickness 
to 4 mm. The sheets are then passed through a pair of groove-surfaced roller presses 
to give the sheets the ribbed appearance as well as to quickly drain off surface water. 
During milling, ensure that sufficient running water is dripped over the sheets. At the end 
of the milling line, the sheets are again washed. The long sheets are then cut into shorter 
lengths before being hung individually on a trolley and allowed to drip in a clean shady 
area for four hours prior to drying them in the smokehouse (Figure 10.16). 
TABLE 10.10 DCL-ALL-ALUMINIUM LATEX COAGULATING TANKS 
Separate sheet tank with smooth sides Continuous sheet tank with V-shaped sides 
Approximate 
inside 
dimension in 
cm or (inch) 
Number 
of 
partition 
Maximum 
working 
depth in 
cm or 
(inch) 
Total 
working 
capacity 
in litre or 
(gallon) 
Approximate 
inside 
dimensions 
cm or (inch) 
Number 
of 
partition 
Maximum 
working 
depth in 
cm or 
(inch) 
Total 
working 
capacity 
in litre or 
(gallon) 
304.80 X 
91.44X40.64 75 34.3 918 
304.80 X 
91.44X 
40.64 
75 37.5 968 
(10'X3'X 
16") (13.5") (202) 
(10'X3'X 
16") (14.75") (213) 
304.80 X 
91.44X40.64 90 34.3 909 
304.80 X 
91.44 X 
40.46 
90 37.5 968 
(10'X3'X 
16") (13.5") (200) 
(10'X3'X 
16") (14.75") (213) 
304.80 X 
91.44 X 45.72 75 39.4 1,054 
304.80 X 
91.44X 
45.72 
75 42.5 1,100 
(10'X3'X 
18") (15.5") (232) 
(10'X3'X 
18") (16.75") (242) 
304.80 X 
91.44X45.72 90 39.4 1,045 
304.80 X 
91.44X 
45.72 
90 42.5 1,100 
(10'X3'X 
18") (15.5") (230) 
(10'X3'X 
18") (16.75") (242) 
Source: DCL = Diethelm Malaysia Sdn. Bhd (Engineering Division) 
336 
337 
USS Production from Smallholdings 
More than 70% of the Malaysian rubber production comes from smallholders. Some 
of them sell their latex to MARDEC and other commercial factories to be processed 
in bulk, either as USS, block or concentrates. However, a small number of them 
still process their latex into USS individually. There are two methods of processing 
smallholders' latex into USS - the coagulating pan and the mini coagulating tank. 
Procedures of both techniques are described below. 
Coagulating pan method. As usual, the processing area and all its equipment 
must be in clean condition, with adequate supply of clean water available. The field 
latex is first diluted with equal volume of clean water. The diluted latex is passed 
through a pair of sixteen mesh per centimetre monel-metal gauze strainers into 
another bucket. The latex is then transferred into the coagulating pan at 5 litres each. 
Formic acid is diluted at 2.5%, that is, 15 ml (equivalent to one table spoonful) in 560 
ml (or two milk tins equivalent) of clean water. The latex is stirred and all the froth 
formed over its surface removed. Diluted acid at 280 ml (equivalent to one milk tin) is 
poured into each pan and thoroughly stirred. The pan is then covered. Coagulation 
takes place in about half an hour. When a clear serum is seen in the pan, clean water 
is poured in to flood the coagulum. Once the coagulum is firm enough to handle, it is 
removed from the pan on to a table and pressed to a thickness of about 2 cm using 
the palm of the hand or a clean iron pipe. The coagulum is then passed through a 
pair of smooth-surfaced rollers three to four times to reduce the thickness to about 4 
millimetres. After that, the rubber sheet is passed through a pair of groove-surfaced 
rollers once. They are then washed and hung individually to drip before drying them 
in the smokehouse (Figure 10.17). 
Mini coagulating tank method. As usual cleanliness is to be emphasised. The field latex 
is first diluted with equal volume of water. The diluted latex is then transferred into the 
mini coagulating tank (40-litre capacity) through a pair of sixteen mesh per centimetre 
monel-metal gauze strainers. Formic acid is diluted to 2.5%, 60 ml in 2.25 litres of 
clean water. The latex is stirred and the froth formed over its surface is removed. The 
diluted acid is poured into the latex and thoroughly stirred. The partition plates are then 
placed in position and the tank is covered. Coagulation usually occurs in about half an 
hour. When a clear serum is seen, the coagulum is flooded with clean water. Once the 
coagulum is firm enough for handling, the first partition plate is removed. 
338 
(a) Gentle stiring to mix acid and latex in pans for coagulation 
(b) Milling of coagulum through smooth roller on the left and 
groove roller on the right 
339 
(c) Dripping and drying of rubber sheets 
Figure 10.17 Processing of USS by pan coagulation method 
This is followed by removing the first coagulum slab. Then, the second plate 
is removed, followed by the coagulum slab. This procedure is continued until all the 
eight coagulum slabs are taken out. The coagulum slabs are passed through a pair 
of smooth-surfaced rollers three to four times until the thickness is reduced to 4 mm. 
The sheets are then passed through a pair of groove-surfaced rollers once. They are 
washed and hung to drip as previously described (Figure 10.18). 
The mini coagulating tank is an improvement over the conventional coagulating 
pan method. It is specially designed for use by smallholders, whose average crop per 
tapping is about 20 litres. It is made of thick aluminium sheet with a size of 43.2 cm x 
31.75 cm x 30.48 cm and a capacity of 40 litres. It offers several advantages over the 
conventional coagulating pan in terms of durability, portability, space, equipment used, 
time saved, and more important of all, quality control. 
SMOKEHOUSE AND THE DRYING OF USS 
The production of USS is incomplete until the sheets produced go through the drying 
process. USS is dried in a smokehouse. A smokehouse can be permanent or semi­
permanent. The permanent smokehouse is made of bricks, while the semi-permanent is 
made of plank or aluminium sheet wall with wooden structure. In the past, smallholders 
used to build small size temporary smokehouses, using easily available jungle rollers 
for the structures, with mud or bamboo stems as walls. But these are not seen anymore 
these days. 
340 
(a) Diluting latex (b) Straining latex 
(c) Coagulating (d) Stirring 
(e) Removing froth (f) Placing partition plates 
(g) Removing coagulum from tank (h) Preparing coagulum for roller 
Figure 10.18 Individual processing of USS by mini coagulating tank 
341 
Since the early thirties, the RRIM (now MRB) had developed a number of 
designs for smokehouses, and in 1964 a new improved series was introduced. They 
have designed RRIM Type 1100, 2200, 3300, and 4400 with capacities of 500, 1,000, 
1,500 and 2,000 kg, respectively. 
Site and Construction 
As the furnace is constructed below ground level, the smokehouse is located on higher 
ground to prevent water seepage. To facilitate transportation, it should preferably be 
built as near to the processing centre as possible. However, is should be sited at least 
15 m away from dwelling houses to reduce fire hazard. 
A smokehouse is almost like any other building, but minus the rooms and other 
amenities found in a normal dwelling. It is, therefore, an empty chamber, but with 
doors and windows known as ventilators. The ventilators are sited on the roof or on 
the upper part of the smokehouse wall, with their openings and shuttings that can be 
controlled from the ground level. The furnace is constructed underground and outside 
the smokehouse. The hot smoke is passed into the smokehouse chamber through a 
tunnel with several outlets along the central length of the floor. The furnace also has a 
door and baffle to facilitate the control of temperature. It is made of fire-bricks laid in an 
arch formation at the upper part (Figure 10.19a). 
In 1983, the RRIM (now MRB) designed another smokehouse (Drawing No 
PT 480). It has a capacity of 120 kg, and is most suitable for use by groups of 
three to five smallholders. The construction is of new concept using two layers of 
aluminium sheet walls for quick heat build-up in the smokehouse chamber. The 
furnace is made of metal cylinder, very much smaller in size than the normal one 
and located above ground level, in the smokehouse chamber itself. Such furnace is 
expected to provide direct heat into the chamber, and at the same time reduces fuel 
consumption (Figure 10.19b). 
In 1986, the RRIM (now MRB) introduced a smokehouse that uses solar 
energy during the day and firewood fuel during the night thus saving fuel cost. But 
such a smokehouse required solar panel and in high capital cost (Figure 10.19c). 
The structural plans of all the RRIM Type Smokehouses are available from MRB on 
request. 
342 
Objectives of Smoking USS 
USS can be dried by atmospheric air, but the process takes more than three weeks. 
As they have to be hung individually, they take a lot of space and cause a lot of other 
inconveniences, too. Furthermore, they get infected by mould (fungus) which brings 
down their quality. With the smokehouse, the drying time can be reduced by about 80% 
and at the same time mould growths can be prevented. USS dried in this way become 
translucent against light and this facilitates its grading. 
Operation of Smokehouse 
Freshly produced sheets that are to be placed in the smokehouse must first be dripped 
off the surface water. This is done by hanging the sheets individually on horizontal 
poles under shade, in a clean area for at least four hours. If they have been kept 
outside for a long period, it is likely that they have mould growing over them. Therefore, 
they should first be washed to remove the mould, hung to drip and later put in the 
smokehouse as previously described. In the smokehouse, the sheets are also hung 
individually on horizontal poles in tiers, the number depending on the size and capacity 
of the smokehouse. Rubber wood of 50-100% dry is usually used as fuel. It is cut to 
the required length of 75 cm with minimum diameter size of 15 cm. For the first round 
of firing, three logs are burnt, with one log added at intervals of four hours to obtain a 
constant temperature. The fuel should never be allowed to produce flame, as this will 
not only produce excessive heat and damage the rubber, but also consume a lot of fuel. 
What is needed is a constant supply of hot smoke. The temperature range required in 
the smokehouse is 50-65 °C, which can be determined by the use of a thermometer. 
The correct temperature can be obtained by using suitable fuel, topping it up at four 
hourly intervals and proper use of the ventilators. The rubber sheets will be dried in 
about 100 hours (Figure 10.20). It is estimated that 1 kg of firewood is required to dry 
1 kg or rubber. 
Rubber sheets can also be dried by other methods, such as heat from the 
burning of oil and electricity. However, at the final stage, the rubber must go through the 
smoking process to conform with the production requirement of RSS. 
343 
(a) RRIM Type smokehouse 
(b) RRIM aluminium-walled smoke cabinet 
(c) Solar-powered smokehouse 
Figure 10.19 Various designs of smokehouse 
344 
(a) Purling fresh USS into smokehouse 
o ^ t M v ^ i i t i i i w r « i 
• ' H « i r ^ ' i i l l i i | i ' ( % m 
(b) Smoking in progress 
T P 
(c) Removing RSS from smokehouse 
Figure 10.20 Smoking of USS 
345 
GRADING OF RSS 
RSS is graded to determine its quality. The different quality is based on the specifications 
of each grade agreed upon internationally. Quality depends on the defects found in the 
RSS that is being graded. This in turn determines its value in terms of price. 
Defects in RSS 
The defects that are found in RSS mostly occur during processing. However, this is not 
realised until the rubber sheet (USS) produced is dried by smoking. The quality of RSS 
is determined by the defects. The following are the types of defect found in RSS, their 
causes and remedies. 
Air bubbles. Small pinhead bubbles are found along the edge of the RSS and 
some are in patches or clusters anywhere over the sheet, while bubbles of irregular 
sizes are dotted all over the sheet. There are also the large bubbles. The small pinhead 
bubbles are caused by incorrect amount of acid not being satisfactorily mixed with 
the latex during processing. The clustered bubbles are caused by latex fermentation 
resulting from the use of contaminated utensils or dirty water. The irregular size dispersed 
bubbles are also caused by latex fermentation before and during latex collection, while 
the large bubbles originate in the smokehouse. The correct amount of formic acid must 
be ascertained to coagulate the latex after standardisation. The diluted acid is added to 
the latex very showly with even stirring. Avoid fermentation of latex by practising strict 
cleanliness and using anticoagulant where necessary. 
Dirt, specks, bark and sand. These can be seen when the RSS is held against 
light. These are due to non-observance of cleanliness requirements when handling 
latex. Latex may not have been strained properly or dirty water has been used. Latex 
must be diluted with clean water and allowed a few minutes rest for the impurities to 
settle and then strained through a suitable strainer, as described earlier. Latex must, at 
all stages, be kept covered. 
Rust. Brownish deposit is seen on the RSS. Sometimes, it is not clearly seen 
until the sheet is stretched or scratched. This is caused by keeping the freshly milled USS 
in poorly ventilated place overnight, or the sheets not being adequately washed during 
milling. It can also be due to low temperature and bad ventilation in the smokehouse 
during the early stage of curing or drying. During milling, the sheets must be washed in 
clean water. Freshly milled sheets or USS must be hung individually to drip in a shaded 
clean and well ventilated place. Proper temperature control and ventilation must be 
maintained during smoking. 
346 
Mould. Patches of greyish fungal growth can be seen on the rubber sheet. This 
is normally favoured by humid conditions. Rubber sheets that are to be dried in the 
smokehouse must be washed off any mould growth over them. If the mould infection 
occurs in the smokehouse, ventilation must be improved and the temperature should 
not fall below 50 °C. If the mould growth occurs during storage, ventilation of the store 
must be improved and the rubber sheets should not be stacked directly on the cement 
floor. Sometimes the poles where the USS are hung in the smokehouse have mould 
growing on them and this in turn infects the USS. Poles must be assured mould-free 
before use. 
Greasy sticky surface. The surface of the RSS is sticky when touched. This 
can be due to excessive use of acid or sodium sulphite in latex. Insufficient washing of 
the sheets during milling can also cause this. The use of firewood producing excessive 
smoke but low heat can also be a cause. Correct amount of acid or sodium sulphite 
should be used. There must be adequate washing of the sheet during milling or soaking 
at the end of the line. Suitable fuel must always be used when drying USS, such as 
rubber wood of 50-100% dry. 
Dark patches. Irregular shaped dark and light coloured patches can be seen 
over the RSS. This can be caused by surface oxidation brought about by the action of 
oxidising enzymes in the latex. Stacking of wet USS can also lead to these. As soon as 
latex coagulates, either in the coagulating tank or pan, clean water must be poured into 
them to keep the coagulum submerged. Wet USS should not be stacked, but should be 
hung individually to drip. 
Blisters. Cracks or microcracks can be seen over the sheet. This can be caused 
by the froth remaining on the surface of the latex during coagulation. They can also be 
due to defective roller presses. All froths formed on the latex surface must be removed. 
The surface of the roller presses must be in smooth condition at all times. 
Thickness or thick ends. Thick portions that are found on the RSS normally 
occur during machining due to overlappings and foldings. They usually do not respond 
to curing or drying in the normal period of time. The gap between the roller presses 
must be of adequate width so that the sheet can easily pass through them. The sheet 
must be rolled to 4 mm thickness. 
347 
RSS Specifications 
The value and price of RSS are influenced by its grade on quality. For example, the 
price of RSS at the Kuala Lumpur market in March 1995 is shown in Table 10.11. It 
shows that the higher the quality of the RSS, the higher is the grade and the higher 
is the price. The price difference between RSS No 1 and RSS No 5 is 17 sen per 
kilogramme. Both grades are processed from naturally clean latex obtained from the 
trees. Unsatisfactory handling and processing technique of the latex caused the drop 
in quality and grade and consequently, the income. 
TABLE 10.11 PRICE OF RSS (SEN/KG) 
Grade of RSS Price Difference Total Differences 
RSS No 1 462.00 
17.00 
RSS No 2 458.50 3.50 
RSS No 3 457.00 1.50 
RSS No 4 450.00 7.00 
RSS No 5 445.00 5.00 
RSS is graded according to its appearance of physical conditions which were 
described earlier. Currently, there are six grades of quality controlled by the International 
Rubber Quality and Packing Conference (IRQPC). They are RSS No 1X , 1,2,3,4 and 
5. The following are the specifications of the different grades. 
RSS No 1X. This type of rubber is produced under conditions in which the 
process is strictly controlled. The sheet must be dry, clean, strong and evenly smoked. 
There should be no oxidised spot, foreign substance, mould, blemish, speck, rust, blister, 
large bubble and translucent stain. Very slight traces of dry mould on the wrapping 
sheets during delivery are permissible. The sheet should not be sticky, undercured, 
oversmoked, opaque and burnt. Scattered pinhead bubbles are permissible. There is 
no international master sample for this grade. 
RRS No 1. The sheet must be dry, clean, strong, and evenly smoked. There 
should be no oxidised spot, foreingn substance, mould, blemish, rust, blister, large bubble 
and translucent stain. Very slight dry mould on the wrapping sheets are permissible. 
Scattered pinhead bubbles and slight specks are permissible too. The sheet should not 
be sticky, undercured, oversmoked, opaque and burnt (Figure 10.21a). 
348 
(a) RSS No 1 (b) RSS No 2 
(e) RSS No 5 
Figure 10.21 Grade of RSS 
RSS No 2. The sheet must be dry, clean, strong, and evenly smoked. There 
should be no oxidised spot, foreign substance, mould, blemish, blister, large bubble and 
translucent stain. The sheet should not be sticky, undercured, oversmoked, opaque and 
burnt. Scattered pinhead bubbles and slight amount of specks are permissible (Figure 
10.21b). If dry mould and rust are found on more than 5% of the bales inspected, they 
can become the basis for objection. 
349 
RSS No 3. The sheet should be dry, clean, strong and evenly smoked. 
There should be no oxidised spot, foreign substance, mould, blister, large bubble and 
translucent stain. The sheet should not be sticky, undercured, oversmoked, opaque 
and burnt. Scattered pinhead bubbles, slight amount of specks and blemishes are 
permissible (Figure 10.21c). If dry mould and rust are extensively found on more than 
10% of the bales inspected, they can become the basis for objection. 
RSS No 4. The sheet should be dry and evenly smoked. There should be no 
oxidised spot, foreign substance, mould, blister and large bubble. The sheet should not 
be undercured and burnt. Slight amount of stickiness, oversmoking, blemishes, specks 
and rusts are permissible. Opaque, pinhead bubbles and translucent stains are also 
permissible (Figure 10.216). If dry mould and rust are extensively found on more than 
20% of the bales inspected, they can become the basis for objection. 
RSS No 5. The sheet should be dry and evenly smoked. There should be no 
oxidised spot and foreign substance and mould. The sheet should not be burnt. Slight 
amount of stickiness, blemishes and blisters are permissible. Slightly undercured sheet 
is permissible too. Oversmoked sheet, specks, rusts, pinhead bubbles, large bubbles 
and translucent stains are also permissible (Figure 10.21e). If dry mould and rust are 
extensively found on more than 30% of the bales inspected, they can become the basis 
for objection. 
Method of Grading 
RSS is graded by visual means. The sheet is held against the light and grading is done 
by just looking at it, taking into account the amount of defects and foreign substances 
found on it, based on the above specifications. The grader is allowed to carry out limited 
removal of the foreign substances or defects on the sheet to raise its quality. The small 
pieces of rubber removed are known as cuttings and they are collected and valued at 
slightly below RSS No 5. Although there are official samples of all the grades (except 
RSS No IX), this method of visual grading can give rise to a lot of objections on the part 
of the consumers, as different graders may have different observations and findings. 
Baling of RSS 
RSS are packed without wrapping in bales of 53 cm x 48 cm x 48 cm with a maximum 
weight of 111.1 kg. After weighing, ten pieces of the RSS are set aside for use as 
wrappers. Talcum powder is spread inside the baling box or frame so that the sheets 
do not stick to it. RSS are arranged neatly in layers in the box and then placed under a 
half-tonne press for 10 minutes. The resultant bale is then wrapped with the ten pieces 
350 
of RSS previously set aside. They are stuck on by piercing a sharp metal piece into the 
bale. Being rubber, they stick very well. Each bale is painted with bale coating solution 
to facilitate labelling (Figure 10.22). The solution can be prepared by soaking 1 kg RSS 
(RSS No 1 cuttings can be used) in 17 litres mineral turpentine. When it is completely 
dissolved, further 8.8 litres of mineral turpentine is added to form a stock solution. At the 
time of application, the stock solution is further diluted with 54 litres of the same solvent. 
Then 7.8 kg of talcum powder is added and thoroughly stirred. This formulation is 
sufficient for 330 bales. 
(a) RSS packed into 111.1 kg bales 
(b) RSS bales coated, stencilled and ready for shipment 
Figure 10.22. RSS bales 
351 
PRODUCTION OF BLOCK RUBBER 
Block rubber production is another process of NR. Considered as modern as opposed to 
the conventional RSS, it was first introduced in 1965. It can be produced from both latex 
and field coagula, or a blend of both. The process involves the coagula to be broken 
up into small bits or crumbs, dried by hot air through a diesel-fired dryer, technically 
graded, baled and efficiently packed. The process facilitates the maximum removal 
of dirt content in rubber, guarantees cleanliness of the product at all stages (from the 
producing factory to the consuming factory) and offers a choice to the consumers as to 
the grade or type of rubber available. It has been gaining popularity from the consumers 
since 1990 and by 1993, 76.6% of the Malaysian rubber was produced in this form. 
Block rubber is exported under the SMR scheme, and currently there are nine grades, 
namely SMR CV60, SMR CV50, SMR L, SMR 5, SMR GP, SMR 10CV, SMR 10, SMR 
20CV and SMR 20. Unlike USS, block rubber is only processed in bulk. 
Block Rubber From Latex 
Field latex is bulked in a bulking tank and thoroughly stirred. Suitable monel-metal 
gauze strainer is used when transferring the latex. The DRC of the latex is determined 
to calculate the quantity of chemicals to be added (Table 10.12). 
TABLE 10.12 CHEMICALS USED IN BLOCK RUBBER (SMR) PRODUCTION 
(PERCENTAGE OF DRC WEIGHT OF LATEX) 
Types of 
chemical 
SMR 
CV60 
SMR 
CV50 
SMR 
L 
SMR 
5 SMR GP 
SMR 
10CV 
SMR 
10 
SMR 
20CV 
SMR 
20 
Latex 
RSS 
or 
USS 
Latex+RSS 
or USS-*- field 
coagulum 
Field coagulum 
Sodium 
metabisulphite 0.04 0.04 0.04 - - - - - -
Hydroxylamine 
neutral 
sulphate 
0.15 0.15 - - 0.16 0.2 - 0.2 -
The chemicals are first mixed with sufficient volume of water or latex and then 
poured into the bulking tank and thoroughly stirred. The latex is transferred into the 
coagulating tank or pit, and coagulated with 2% formic acid, the quantity depending on 
the titration value to coagulate the latex at pH 5.2. The diluted acid is slowly poured 
into the latex and evenly stirred. If a coagulating pit is used, the latex and the acid 
352 
can be released into it simultaneously, after making proper adjustment to their rates 
of flow. When a clear serum has been formed over the coagulum, the tank (or pit) is 
flooded with clean water to submerge the coagulum. Coagulum slabs produced by 
pit coagulation are thick and must first go through a machine to reduce the thickness. 
They are then passed through two sets of crepers, and then through a shredder or 
extruder to break them into fine crumbs. All through the milling process, water is 
continuously dripped over the crepes. The crumbs are again washed and then placed 
in dryer boxes for dripping and later put into the drying chamber for four hours. The 
crumbs are dried with heat at 110 °C in an oil- or gas-fired dryer. The dried crumbs 
are weighed to 33 1/3 kg lots. They are then pressed to form compact bales with 
dimensions of 675 mm x 330 mm x 170 mm. Samples from 10% of each day's 
production are taken to determine the grade technically (Table 10.13). The bales are 
wrapped in transparent polythene sheet of 0.03 mm to accommodate thirty bales with 
a total weight of 1 tonne or 1,425 mm x 1,100 mm x 1,080 mm for thirty six bales at 
1.2 tonne according to request. There are also request for special polythene shrink 
wrapping packings with wooden pallet used as the base (Figure 10.23). 
(a) Creping and crumbing of coagulum 
(b) Placing crumbs in dryer box 
353 
(d) Baling 
(e) Packing of rubber bales into pallet ready 
for export 
Figure 10.23 Processing of block rubber 
354 
Block Rubber from Field Coagula 
The field coagula are first soaked in water for some time to soften and pre-clean them, 
and then fed into size-reducing machine such as the prebreaker or granulator. The 
rubber is then passed through four sets of creping machines. During the last stage of 
creping, crumbing agent (at 0.05% of its DRC) is dripped over the crepes. The crepes 
are then put into the shredder or extruder. All through the milling process, clean water 
is continuously dripped over the crepes. The fine crumbs produced are washed, dried, 
graded and packed in the usual manner. Due to the higher dirt content of the raw 
materials, field coagula are only suitable for the SMR 10 and 20 grades. 
Block Rubber from Latex, USS or RSS and Field Coagula 
This is a blending and coagulation process. The raw materials are 30% latex, 30% USS 
(or RSS) and 40% field coagula. This ratio is according to their DRC weights. 
The percentage of USS (or RSS) and field coagula are only determined after 
creping them. The field coagula are pre-cleaned and milled into a blanket crepe. USS 
(or RSS) are also milled into a blanket crepe. Both types of blanket are then blended by 
passing them through four sets of creping machines. During the final stage, crumbing 
agent at 0.05% of its DRC weight is applied on the crepe. The crepe is then put through 
the shredder or granulator. The fine crumbs produced are washed and placed in 
the coagulating tank or pit. In the meantime, the 30% latex component is prepared 
in a bulking tank. Crumbing agent at 0.05% from the DRC weight of the latex and 
hydroxylamine neutral sulphate at 0.15% from the DRC weight of all the raw materials 
are mixed into the latex and thoroughly stirred. The latex is then transferred into the 
coagulation tank (or pit) containing crumbs of the other raw materials, together with 2% 
formic acid, the quantity of which has been adjusted. The resultant coagulum slabs are 
creped, crumbed, washed, dried, graded and packed in the usual manner. This type of 
rubber is graded as SMR GR 
PRODUCTION OF LATEX CONCENTRATES 
Not at all rubber products can be made from sheet or block rubber. There are also 
products, such as dipped, cellular or foam rubber goods and others that require latex as 
the raw material. This necessitates transport of latex to far away destinations to reach 
the consumers. To reduce packing, storage, and transportation costs, latex must be 
concentrated to reduce the water content which forms the bulk of the latex but having no 
monetary value. Besides, high DRC latex is also required for the manufacture of latex 
355 
TABLE 10.13 BLOCK SMR SPECIFICATIONS 
Parameter 
SMR 
CV60 
SMR 
CV50 SMR L SMR 5* SMR GP 
SMR 
10CV SMR 10 
SMR 
20CV SMR 20 
Latex USS, RSS or ADS 
Latex + RSS or 
USS + 
field coagulum 
Field coagulum 
Dirt (max, % wt) 0.02 0.02 0.02 0.05 0.08 0.08 0.08 0.08 0.08 
Ash (max, % wt) 0.50 0.50 0.50 0.60 0.75 0.75 0.75 0.75 0.75 
Nitrogen (max, % wt) 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 
Volatile matter (max, % wt) 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 
Wallace rapid plasticity (Po) 
(min) - - 3/5 30 - - 30 - 30 
PRI (min,%)b 60 60 60 60 50 50 50 40 40 
Lovibond colour: 
invidual value (max) - - 6.0 - - - - - -
range (max) - - 2.0 - - - - - -
Mooney viscosity: 
ML(1'+4")100°C° 60 ±5 50 ±5 - - 655(+7,-5) c - c -
Cure" R R R - R R - R -
Colour coding marker Black Black Light green 
Light 
green Blue Magenta Brown Yellow Red 
Plastic wrap colour Trans­parent 
Trans­
parent 
Trans­
parent 
Trans­
parent Transparent 
Trans­
parent 
Trans­
parent 
Trans­
parent 
Trans­
parent 
Plastic strip colour Orange Orange Trans­parent 
Opaque 
white 
Opaque 
white 
Opaque 
white 
Opaque 
white 
Opaque 
white 
Opaque 
white 
"Two sub-grade of SMR 5 are SMR 5RSS and SMR 5ADS, which are prepared by direct baling of RSS and ADS, respectively. 
"Special producer limits and related controls are also imposed by the MRB to provide additional safeguards. 
The Mooney viscosities of SMR 10CV and SMR 20CV are at present not of specification status. They are, however, controlled at the producer end to 60(+7,-5) 
for SMR 10CV and 65(+7,-5) for SMR 20CV. 
"Rheograph and cure test data (delta torque, optimum cure time and scorch) are provided. 
products. In 2007, Malaysia produced 176,363 tonnes of latex concentrates, which was 
about 14.7% of the annual rubber production. 
To obtain high quality latex concentrate, proper preservation of the latex in the 
field is very important. Ammonia at 0.3% is normally used as an anticoagulant, as is 
found to be very effective in preventing bacterial growth in latex. Bacteria can cause 
the development of VFA in latex. The VFA number of field latex indicates the degree 
of biodegradation which has taken place. Lower VFA number means the latex has 
been well preserved and is suitable for concentration. A well preserved field latex will 
have a VFA number of between 0.02 and 0.04. Latex with VFA number exceeding 0.05 
is not suitable for concentration. Another factor which is also important is the DRC 
of the latex. Latex of below 25% DRC is unsuitable for concentration. For optimum 
processing efficiency, latex with a minimum of 30% DRC is required. 
In the production of latex concentrates, the field latex is transferred into a 
bulking tank through suitable monel-metal gauze strainer. After the necessary tests 
have been made, the latex is transferred into a settling tank overnight to settle all its 
impurities. There are three methods by which natural rubber latex can be concentrated. 
They are the centrifugation, the creaming and the evaporation process. Among them, 
the centrifugation process is widely practised in Malaysia. 
Centrifugation 
The most common latex centrifuge machine is the Alfa Laval type (Figure 10.24). The 
basic principle of this process involves the breaking up of the latex by rotating it inside 
several conical discs using a rotating bowl at a high speed of 7,000 rpm. 
This results in the separation of the lighter rubber particles from the denser 
components. The concentrated latex of about 60% DRC moves in towards the centre of 
rotation, while the skim part of about 5% DRC moves outwards. The latex concentrate 
and the skim latex then go through separate channels into two gullies where they are 
collected. When completed, the latex concentrate is again preserved. There are five 
preservative systems for latex concentrates (Table 10.14). 
Sometimes, it is also important to enhance the mechanical stability time (MST) 
of the latex to increase its resistance against mechanical shearing during subsequent 
pumping and stirring. For this purpose, lauric acid or ammonium laurate is used at 0.01-
0.05%. Overboosting is not recommended as it can cause problems in latex destabilisation 
at the consumer's factory. MST builds up during storage and this must be considered when 
357 
Incoming latex 
Latex concentrate 
channel 
1 ! Distributor 
Separator 
Skim latex 
channel 
Figure 10.24 Alfa Laval latex centrifuge machine 
TABLE 10.14 PRESERVATIVE SYSTEMS FOR LATEX CONCENTRATES 
System Preservative 
HA 0.7% ammonia 
LA-SPP 0.2% ammonia + 0.2%SPP 
LA-BA 0.02% ammonia + 0.2% boric acid + 0.05% lauric acid 
LA-ZDC 0.2% ammonia + 0.1% ZDC + lauric acid 
LA-TZ 0.2% ammonia + 0.013% ZnO + 0.05% lauric acid 
determining the exact level of lauric acid to be used. The consumers are more concerned 
with the supply of latex concentrates that comply with specifications. Therefore, each 
consignment of latex concentrate must have the following specifications as shown in 
Table 10.16. Latex concentrates are packed in drums or tanks before shipment. 
358 
TABLE 10.15 BASIC TEST AND SPECIFICATION LIMITS OF CENTRIFUGED LATEX 
CONCENTRATE 
Test properties ISO 2004 specification 
Total solids content (%, min) 61.5 
DRC (%, min) 60.0 
Alkalinity (g ammonia per 100 g water) 1.6 min (HA) or 0.8 max (LA) 
Mechanical stability time (s, min) 650 
VFA number (max) 0.20 or as agreed by consumer and pruducer 
Potassium hydroxide (max) 1.00 or as agreed by consumer and pruducer 
Creaming Process 
In this process, a compound that acts as a creaming agent is used to cause the rubber 
particles in latex to agglomerate loosely into larger groups which rise to the surface to 
form a cream. The most common creaming agent is ammonium alginate. The process 
in briefly described by the following flow diagram {Figure 10.25). 
Field latex 
Add oleic Add ammonium 
acid alginate 
< 
Bulking 
Add ammonia J 
Steaming 
Cream Serum 
Serum rubber 
Add sulphuric 
acid 
Storage tank 
Drum or tank Packing 
Figure 10.25 Flow diagram of the creaming process 
359 
Evaporation Process 
This process involves circulating the latex through a tubular heat exchanger in a specially 
designed evaporating unit. The evaporation is carried out in a suitable chamber under 
reduced pressure. Recycling the partially concentrated latex is necessary until the 
desired DRC is achieved. Ammonia is commonly used as preservative in this process. 
The concentrated latex is treated and packed in the usual manner. 
Modified Latex Concentrates 
Besides latex concentrates described above, there are also several other types of 
modified concentrates available for specific uses. These are briefly described below. 
High DRC latex. This latex contains 64-67% DRC. It is prepared by double 
centrifugation as described earlier. To obtain such latex, a specially modified bowl with 
specially adjusted sizes of feed tubes and skim screws used in the centrifuge machine. 
Its latex properties are suitable in adhesives preparations and dipped products. 
Purified latex. This latex contains low non-rubber solids content. It is prepared 
by two or three centrifugations. The reduction of non-rubber solids, especially proteins, 
in the latex, renders the latex clean with low water absorption properties. This can offer 
special advantage to products like electricians' gloves, insulators, human body parts 
and prophylactics. 
Prevulcanised latex. This latex is prepared by heating latex concentrate with 
vulcanising ingredients. When using such latex in product manufacture, vulcanisation 
of the finished product is not required. Therefore, the compounding process can be 
simplified. This latex is suitable in the manufacture of dipped and cast goods, textile 
combining and carpet backing compounds. 
Freez-thaw-stabilised (FTS) latex. When concentrated latex is frozen to below 
0 °C, colloidal destabilisation takes place, and when the latex is thawed it becomes 
viscous and unstable. If the frozen condition is prolonged, coagulation of the latex may 
take place. FTS latex can be prepared by adding 0.2% of latex weight sodium salicylate 
and 0.04-0.05% of latex weight lauric acid. Although these chemicals do not prevent 
freezing, they can enhance latex stability during freezing and enables the latex to regain 
fluidity on thawing. 
FTS latex is suitable for storage and can be used during the winter period in 
temperate countries. 
360 
Methyl-methacrylate (MG) latex. When methyl-methacrylate is polymerised in 
NR latex using a free radical catalyst, a large proportion of the polymethylmethacrylate 
that is formed, is grafted chemically to the molecular chain of NR. Two such types of 
latex are being produced, with the trade names of Heveaplus MG 30 and MG 49, which 
contain 30% and 49% by weight, methylmethacrylate, respectively. They are supplied 
at 40-55% total solids content and have several specific uses, such as adhesives for 
bonding dissimilar surfaces and reinforcing agents in certain applications. 
Low constant viscosity (LCV) latex. This is standard latex concentrate which is 
prepared from latex of soft clones and treated with 0.15 phr of hydroxylamine. Addition 
of hydroxylamine to the concentrate retards the rate of increase in viscosity of the rubber 
in the latex during storage. LCV latex is produced to meet a Mooney Viscosity of not 
greater than ninety units when reaching the consumer. The main advantage of such 
latex is in the application of adhesives, in which the low viscosity permits the use of 
lower levels of tackifying resins in the formulation of the adhesives. 
Skim Latex 
In the process of latex centrifugation, the diluted part known as skim is separated. This 
contains 4-7% DRC. Part of the skim is used locally in the mixing process with other 
rubbers. The balance is processed into skim crepe or block rubber such as MARUB. 
Skim latex is high in ammonia content. Therefore, it is necessary to reduce the ammonia 
by allowing it to evaporate naturally. However, this process can be speeded up by 
the rotating-disc deammoniation system. It comprises a column through which air and 
skim latex are passed counter-current to one another. The column is provided with an 
axially positioned rotatable shaft upon which are located a number of discs. It is further 
provided with a series of redistribution trays located at intervals along its length. The 
latex showers from its feed distribution tray on the rotating disc below. The latex flowing 
downward, counter-current to the air flow, is dispersed by the rotating discs. Latex 
which splashes on the walls of the column is collected on the latex redistribution trays. 
Under suitable conditions, the dispersion produces fine latex droplets. 
This type of aeration reduces the ammonia content to less than 0.1% w/w of 
skim latex, which can become autocoagulated in a few days. This can also be speeded 
up by using sulphuric acid as the coagulant. The quantity of acid required is calculated 
stoichiometrically to neutralise the ammonia. The acid is added to the latex as a 10% 
w/v aqueous solution and quickly stirred. Coagulation takes place in a few minutes. 
The coagulum produced is washed, creped, crumbed, dried and packed as in other 
block rubber production. 
361 
Although the properties of skim rubber vary from different sources, the production 
from each factory is usually uniform. Test analysis normally shows the following values. 
(Table 10.16). 
TABLE 10.16 TEST ANALYSIS OF SKIM RUBBER 
Properties Typical value 
Dirt (max, % wt) 0.05 
Ash (max, % wt) 1.00 
Nitrogen (max, % wt) 1.00-4.00 
Acetone (max, % wt) 3-15 
Wallace plasticity (Po) 35-45 
PRI 40 
MOD (kg cnr2) Upto 15 
Colour Varies 
RHC (min, %) 90-60 
362 
G L O S S A R Y 
Abdomen 
the region of the body of a vertebrate that contains the viscera other than the heart and the lung; 
in mammals it is separated from the thorax 
Acid 
any substance that dissociates to yield a sour corrosive solution containing hydrogen ions, having 
a pH of less than 7 and turning litmus red 
Acid equivalent 
amount of active ingredient expressed in terms of its parents 
Active ingredient 
the component in a chemical formulation that gives the effect 
Alkali 
a soluble base or solution of a base, a soluble mineral salt that occurs in arid soils and some 
natural waters 
Alluvium 
a fine-grained fertile soil consisting of mud, silt and sand deposited by flowing water on flood 
plains, in river beds and in estuaries 
Amine 
an organic base formed by replacing one or more of the hydrogen atoms of ammonia by organic 
groups 
Anther 
the terminal part of a stamen consisting of two lobes, each containing two sacs in which the pollen 
matures 
Anticoagulant 
a chemical that can delay the coagulation of latex 
Aqueous concentrate 
a concentrated solution that forms a solution when water is added and stirred 
Aqueous solution 
a solution that contains water 
Arboricide 
a chemical that kills trees 
Aromatic compound 
a compound obtained from benzene hydrocarbon 
Arthropod 
any invertebrate of the phylum Arthropoda, having jointed limbs, a segmented body and an 
exoskeleton made of chitin 
363 
Auxine 
any of the various plant hormones, such as indoleacetic acid that promotes growth and controls 
fruit and flower development 
Avenue planting 
a planting design in which the inter-row distance is very wide-more than a rectangle but less than 
a hedge 
Axillary bud 
the bud situated between the stem and the leaf axil 
Bacteria 
a minute one-cell plant without chlorophyll 
Baffle 
a plate or mechanical divide to restrain or regulate the flow of fluid, smoke, light, or sound such 
as the one found in the smokehouse furnace 
Bare or exposed soil 
a soil without any cover plant growing over its surface 
Bark gauge 
an instrument used for measuring the thickness of the bark of the rubber tree 
Basic slag 
a furnace slag produce in steel making, containing large amounts of calcium phosphate used in 
a fertilizer 
Biscuit 
a rubber sample used in determining the dry weight of field latex by the laboratory and chee 
methods 
Blanket hectare 
a full hectare of an area 
Blight 
any plant disease characterised by weathering and shrivelling but without rotting 
Blind contour 
a contour line that does not begin from the base line, sometimes known as filler contour line 
Breeding 
the process of bearing offsprings in plants and animals; reproduction 
Budded stump 
a stock plant which has been successfully budded and extracted for transplanting 
Bud grafting 
taking a bud from a selected tree and allowing it to grow on a stock plant; it is one of the methods 
of vegetative propagation 
364 
Budpatch 
a bud slip which has been stripped of its wood, trimmed and ready to be inserted in the stock plant 
for the purpose of budgrafting 
Bud slip 
a bud which has been sliced with part of the wood from its budstick, from it a budpatch is obtained 
for budgrafting 
Buttress 
a root that supports the trunk of a tree usually growing from the stem 
Calibration 
markings on a scale of measuring instruments so that the reading can be made in appropriate 
unit 
Callus 
a mass of hard protective tissue produced in woody plants at the site of an injury 
Cambium 
a meristem that increases the girth of stems and roots by producing additional xylem and 
phloem 
Carpel 
the female reproductive organ of flowering plants consisting of an ovary style and stigma the 
carpals are separate or fused to form a single pistil 
Cell 
the smallest unit of an organism the carpals that is able to function independently it consist of a 
nucleus containing the genetic material 
Cell nucleus 
the source of life in a cell 
Centrifuge 
rotating machines that separate liquids from solids or dispersions of and liquid in another by 
centrifugal force action, such as the one used for concentrating latex 
Ceramic 
a hard brittle material by firing clay and similar substance 
Cess 
duty or tax 
Chloroplast 
a plastid containing chlorophyll and other pigments occurring in plant that carry out 
photosynthesis 
Chromosome 
any of the microscopic rod-shaped structures that appear in a cell nucleus during cell division 
consisting of nucleoprotein arranged into units (genes) that are responsible for the transmission 
of hereditary characteristics 
365 
Classic 
composed of fragments of pre-existing rocks 
Clone 
a group of cell of the same genetic constitution that are descended from a common ancestor by 
vegetative reproduction 
Coagulation 
causing a change from liquid to a soft solid mass, e.g coagulation of latex to form coagulum 
Coagulum 
latex which has coagulated 
Collar 
the part of a plant between the base of the stem and the tap root 
Colloidal 
a mixture having particles of one component with diameters between 10 7 m and 10 9 m, suspended 
in continuous phase of another component; the mixture has properties between those of a solution 
and a fine suspension 
Columnar 
elongated soil structure 
Compact 
closely packed together solid and firm such as compact soil 
Composite 
composed of separate parts 
Compost 
a mixture of organic residues for use as fertiliser 
Configuration 
the shape of a molecule as determined by the arrangement of its atoms 
Conservation 
protecting from damage or loss e.g. soil conservation 
Constituent 
a part of a whole component 
Constraint 
restrictive condition 
Contact herbicide 
a chemical that kills herbs by touch 
Contour line 
a line drawn on a map showing points of the same height from sea level 366 
Core stump 
a large budded plant which has been extracted with Its roots enclosed in a soil core still intact for 
transplanting 
Cortex 
the unspecialised tissue in plant stems and root between the vascular bundles and the epidermis 
the outer layer of a part such as the bark of a stem 
Crepe 
having ridged or crinkled surface such as crepe rubber 
Crotch 
a forked region formed by the junction of two members such as the branch crotch of a plant 
Crown 
the top section of a plant or tree which consists of the branches and the leaves 
Cumulative effect 
growing in quantity, strength, of effect by successive or gradual steps 
Defoliant 
a chemical used in shedding the leaves of plants 
Degraded or exhausted soil 
soil which has been overused by improper cultivation 
Diagnostic 
of relating to, or of value in diagnose any symptom that provides evidence for making a specific 
diagnosis 
Dicotyledon 
any flowering plant of the Dicotyledonea having two embryonic seed leaves 
Distillation 
the process of evaporating a liquid and condensing its vapour 
Dormant bud 
a bud which has not yet developed into a shoot 
Dorsal 
of relating to or situated on the side of an organ that is directed away from the axis 
Drainage area 
the area of bark in which latex is drawn when tapping is done 
Electrolyte 
a solution or molten substance that conducts electricity 
Element deficiency 
lacking in any nutrient in plants and animals 
367 
Ellipse 
a closed conic section shaped like a flattened circle and formed by an inclined plane that does 
not cut the base of the cone 
Empirical 
derived from or relating to experiment and observation rather than theory 
Emulsion 
a colloidal in which both phases are liquids like oil-in-water emulsion 
Emulsifiable concentrate 
a concentrated solution and emulsifier in an organic solvent that will form an emulsion 
spontaneously when water is added or stirred 
Endemic 
present within a localised or peculiar to plant in an area such as an endemic disease 
Environmax 
pertaining to a particular area or locality 
Environment 
area or surrounding 
Enzyme 
a group of complex proteins or conjugated proteins that are produced by living cells and act as 
catalysts in specific biochemical reactions. 
Epical 
a bud situated at top of plant 
Equation 
a mathematical statement that two expressions are equal 
Erosion 
the wearing away of soil from the earth surface by the action of water, wind , and sunlight 
Evaporation 
the change from a liquid or solid state to a vapour 
Exudation 
the release of sap from the rubber tree through the pores 
Exploitation 
the act of extracting latex yield from the rubber tree, which includes tapping, puncturing and 
stimulation 
Extruder 
a machine that produces moulded sections of rubber by ejection under pressure from a suitable 
shaped nozzle 
Fertilisation 
the union of male and female gametes during sexual reproduction to form a zygote 
368 
Flux 
a chemical used to increase the fluidity of refining slogs in order to promote the rate of chemical 
reaction 
Foliage 
the total green leaves on a plant 
Friable 
easily broken up; crumbly, loose such as friable soil 
Fructification 
any spore-bearing structure in fungi 
Fruit body 
the part of a fungus in which the spores are produced 
Fungicide 
a chemical that kills fungi 
Fungus 
any plant lacking in chlorophyll, leaves, true stem and root reproduced by spores and living as 
saprophyte or parasite 
Furnace 
an enclosed chamber in which heat in produced by burning fuel, such as wood 
Gangue 
valueless and undesirable material such as quartz in small quantities in an ore 
Genesis 
a beginning of origin and anything 
Genetic 
a leaf of a plant turning yellow due to its genes or heredity 
Geology 
the scientific study of the origin, history , structure and composition of the earth 
Gleyzation 
a soil-forming process which results in the development of bluish-grey compact sticky soils known 
as gluey soils 
Globule 
a small drop of liquid 
Gouge 
a tapping knife that cuts by pushing 
Granulator 
a machine that produces granulated products 
369 
Gutta percha 
any of several tropical trees of the sapotaceous genera Palaquium and Payena. 
Gynoceum 
the carpels of a powering plants collectively 
Habitat 
the natural home of a plant or animal 
Hedge planting 
a planting design in which the inter-rows are very far apart, more than a avenue 
Herb 
a seed bearing plant whose aerial parts do not persist above ground at the end of the growing 
season; herbaceous plant 
Herbaceous 
related to plant that are fleshy as opposed to woody 
Heterogeneous 
composed of unrelated or differing parts or elements not of the same kind or type 
Horizon 
a layer in a soil profile having particular characteristics 
Hormone 
an organic compound produced by a plant that is essential for growth 
Host plant 
a plant that nourishes and supports a parasite 
Humus 
a dark brown or black colloidal mass or partially decomposed organic matter in the soil and 
therefore important for plant growth 
Hybrid 
a plant or animal resulting from a cross between genetically unlike individuals 
Immaturity 
not fully grown or developed; in rubber it is young and not yet ready for tapping 
Immunity 
the ability of an organism to resist disease by producing its own antibodies or by inoculation 
Inarching or approach grafting 
to graft a plant by uniting stock and scion while both are growing independently 
Included bark the bark of a plant that grows into a crack at the branch fork, where water can seep in, thus causing r t and stem split 
370 
Inert ingredient 
inactive component of a mixture 
Inland soil 
soil away from the coastal areas 
Inoculate 
to introduce the causative agent of a disease into the body of a plant or animal in order to induce 
immunity, to introduce micro-organisms, especially bacteria into a plant 
Inorganic material 
a material which is not organic; not having the structure or characteristic of living organisms 
Input 
a resource required in a production 
Insect 
any small air-breathing arthropod of the class Insecta, having a body divided into three - head, 
thorax and abdomen and three pairs of legs and in most species two pairs of wings 
Insecticide 
a chemical that kills insects 
Integument 
any outer protective layer or covering, such as a cuticle, seed coat, rind or shell 
Interaction 
a mutual or reciprocal action; the transfer of energy between elementary particles, between a 
particle and a field or between fields 
Invertebrate 
any animal lacking a backbone, including all species not classified as vertebrates 
Ion 
an electrically charged atom or group o atoms formed by the loss or gain of one or more 
electrons 
Jebong 
the tapping knife that cuts by pulling 
Jet 
a thin stream of liquid or gas forced out of a small aperture or nozzle 
Kink 
twisted such as the twisted condition of a tree trunk 
Lamella 
any of the membrane in a chloroplast 
Larva 
an immature free living form of many animals that develops into a different adult form by 
metamorphosis 
371 
Latent bud 
a bud which has the potential of producing a shoot but not obvious or explicit 
Laterite 
any of a group of residual deposits of ferric and aluminium oxides formed by weathering of rocks 
in tropical regions 
Latex 
the white fluid that oozes out of the bark of the rubber tree when inflicted 
Latosol 
a suborder of zonal soils, including soils formed under forested tropical humid conditions, 
characterised by low silica-sesquioxide ratios of the clay fractions, low base-exchange capacity 
of the clay content of most primary minerals, low content of soluble constituents, high degree of 
aggregate stability and usually having a red colour 
Leach 
to lose or cause to lose soluble substance by the action of percolating liquid 
Leader branch 
the main central branch situated between the lowest crotch and the tip of the tree 
Leaf axil 
the stalk connecting the leaf petiole and the stem or branch 
Legume purification 
removal of weeds growing within a planted legume cover crop to obtain pure legume cover 
Lenticel 
any of numerous pores in a stem of a wood plant allowing exchange of gases between the plant 
and the exterior 
Lethal dosage 
the amount of the active ingredient in a chemical required to kill 50% of the test animal 
population 
Loam 
soil made up of a mixture of clay, sand and decaying organic material 
Logarithm 
the exponent indicating the power to which a fixed number, the base must be raised to obtain a 
given number or variable; it is used to simplify multiplication and division 
Macerator 
a machine used to soften or separate raw rubber as a result of soaking 
Mammal 
any animal of the Mammalia, a large class of warm-blooded vertebrates having mammary glands 
in the female, a thoracic diaphragm and a four-chambered heart 
372 
Masterbatch 
a mixture of ingredients at higher concentrations, usually for storage, which can or must be 
reduced (diluted) further before use, e.g. latex masterbatch treated with preservatives in the 
production of latex concentrates 
Mature 
fully grown, ripe; the rubber tree is considered matured when the trunk size reaches a girth of 45 
centimetres 
Medulla 
the innermost part of an organ or structure; the centre part of the rubber tree stem called pith 
Meniscus 
the curved upper surface of a liquid standing in a tube, produced by the surface tension 
Meristematic 
a plant tissue responsible for growth, whose cells divide and differentiate to form the tissues and 
organs of the plant 
Metabolism 
the sum total of the chemical processes that occur in living organisms, resulting in growth, 
production of energy, and elimination of waste material 
Metarmorphosis 
the rapid transformation of a larva into an adult that occurs in certain animals, e.g. the stage 
between tadpole and frog or between chrysalis and butterfly 
Micro-organism 
any organism, such as bacterium, protozoan or virus of microscopic size 
Micropyle 
a small opening in the integument of a plant ovule through which the male gametes pass 
Miscible 
capable of mixing, e.g. alcohol is miscible with water 
Mitosis 
a method of cell division, in which the nucleus divides into daughter nuclei, each containing the 
same number of chromosomes as the parent nucleus 
Modulus 
a coeficient expressing a specified theory of a specified substance 
Moisture 
water or other liquid diffused as vapour or condensed on or in objects 
Molecule 
the simplest unit of a chemical compound that can exist consisting of two or more atoms held 
together by chemical bonds 
373 
Mollusc 
any invertebrate of the phylum Mollusca, having a soft unsegmented body and often a shell, 
secreted by a fold of the skin (the mantle), such as snails, slugs, clams, mussels, cuttlefish, 
octopuses, etc. 
Monel-metal 
any of various corrosion-resistant alloys containing 28% copper, 69% nickel and aluminium 
Monoclone 
consisting only of one clone 
Monomer 
a compound whose molecules can join together to form a polymer 
Mottling 
colour with streaks or blotches of different shades in a soil, usually in water-logged areas 
Mulch 
dead plant and other materials spread over the soil surface, especially around planted crops to 
keep the soil surface cool and moist 
Mycelium 
the vegetative body of fungi, a mass of branching filaments (hyphae) that spread throughout the 
nutrient substratum 
Necrosis 
death of plant tissue due to disease 
Noxious weeds 
poisonous or harmful unwanted plants 
Nozzle 
a projecting pipe or spout from which fluid is discharged 
Nuclei 
plural form of nucleus 
Nucleus 
a spherical or ovoid cellular organelle, bounded by a membrane, that consists of DNA, RNA, 
etc., and is responsible for growth and reproduction of the cell and the transmission of hereditary 
material 
Nutrient 
any of the mineral substances that are absorbed by the roots of plant for nourishment 
Optimum 
a condition, degree, amount of compromise that produces the best possible result 
Organic material 
a material derived from plant or animal parts or organs 
374 
Organism 
any living plant or animal including any bacterium or virus 
Orifice 
an opening or mouth into a cavity; vent; aperture, such as an orifice of a sprayer nozzle 
Osmosis 
the passage of solvent molecules from a less concentrated to a more concentrated solution 
through a semi-permeable membrane until both solutions are of the same concentration 
Ovary 
the hollow basal region of a carpel containing one or more ovules 
Ovule 
a small body in seed-bearing plants that contains the egg cell and develops into the seed after 
fertilisation 
Oxidise 
to undergo or cause to undergo a chemical reaction with oxygen, as in the formation of oxide 
Ozone 
a colourless gas with chlorine-like odour, formed by an electric discharge in oxygen 
Parabola 
a conic section formed by the intersection of a cone by a plane parallel to the generator 
Parasite 
a plant or animal that lives in or on another (host) from which it obtains nourishment 
Parenchyma 
a soft plant tissue consisting of simple thin-walled cells with intervening air spaces 
Parent material 
the unconsolidated and more or less chemically weathered mineral or organic matter from which 
the solum of soils is developed by pedogenic process 
Pendant 
hanging, dangling, soft, not fully developed, such as the very young rubber leaves just after the 
leaflet stage of growth 
Perennial crop 
a crop that completes its life cycle in more than two years, such as rubber 
Periodic 
happening or recurring at intervals; intermittent 
Petiole 
the stalk by which a leaf is attached to the plant; leaf stalk 
Petiolule 
the short stalk by which the leaf is attached to the petiole 
375 
Petrolatum substance 
a translucent gelatinous substance obtained from petroleum, used as a lubricant and in medicine 
as an ointment base and protective dressing 
Phelloderm 
a layer of thin-walled cells produced by the inner surface of the cork cambium 
Phellogen 
the technical name for the cork cambium 
Phloem 
tissue in higher plants that conducts synthesised food substances to all parts of the plant 
Photosynthesis 
the synthesis of organic compounds from carbon dioxide and water (with the release of oxygen) 
using light energy absorbed by chlorophyll 
Pith 
the central core of unspecialised cells surrounded by conducting tissue in the stem 
Planting density 
the number of trees suitable for planting in a specified size area, e.g. per hectare 
Planting design 
the planting arrangements of trees or crops in an area 
Plastid 
any of various small particles in the cytoplasm of the cells of plants and some animals which 
contains pigments, starch oil, protein, etc. 
Pneumatic 
containing pressurised air as in pneumatic tyre 
Pod 
the seed case as distinct from the seeds 
Pollarding pruning 
a tree at the crown level to induce branching or to lighten the tree 
Pollen 
fine powdery substance produced by the anthers of seed-bearing plants, consisting of numerous 
fine grains containing the male gametes 
Pollination 
the transfer of pollen from the anther to the stigma of a flower 
Polyclone 
consisting of more than one clone 
Polyhedron 
a solid figure consisting of four or more plane faces, pairs of which meet along an edge, three or 
more edges meet at a vertex 
376 
Polyisoprene 
polymeric forms of isoprene occurring in rubber 
Polymer 
a naturally occurring or synthetic compound that has large molecules made up of many relatively 
simple repeated units 
Post-emergent herbicide 
a chemical that kills herbs that are already growing 
Potential of hydrogen (pH) 
a measure of the acidity or alkalinity of a solution equal to the common logarithm of the reciprocal 
of the concentration of hydrogen ions in moles per cubic decimeter of solution; pure water has a 
pH of 7, acid solution less than 7 and alkaline solution greater than 7 
Precipitation 
a process in which a dissolved substance separates from solution as a fine suspension of solid 
particles 
Precoagulate 
latex becomes partial solid naturally, usually by bacterial action 
Predator 
an animal that lives by eating other animals 
Pre-emergent herbicide 
a chemical that kills herbs at the seed stage (before it germinates) 
Premium 
an amount paid as a bonus in addition to the standard rate, for excellent production 
Prism 
a polyhedron having parallel, polygonal, and congruent bases and sides that are parallelograms 
Prismatic 
concerned with, containing or produced by a prism 
Profile 
a vertical section of soil from the ground surface down to the parent rock showing the different 
horizons 
Protectant 
a chemical applied to any part of a plant to prevent disease infection 
Protoplasm 
the living contents of a cell; a complex translucent colourless colloidal substance differentiated 
into cytoplasm and nucleoplasm 
Protozoan 
any minute invertebrate of the phylum Protozoa 
377 
Prune 
to cut any part of the plant, especially the branches 
Pupa 
an insect at an immobile nonfeeding stage of development between larva and adult, when many 
internal changes occur 
Quicklime 
calcium oxide 
Quincunx 
a group of five objects arranged in a shape of a rectangle with one at each of the four corners and 
the fifth in the centre 
Radical 
the root that emerges when the seed germinates 
Random 
not following any pre-arranged order 
Relief 
variation in altitude in an area; difference between the highest and lowest level of an area 
Renewed or regenerated bark 
the bark of the rubber tree which grows again after tapping it 
Repellant substance 
a chemical applied on trees or around the plantation to keep away pests 
Residual effect 
relating to or designation a residue or remainder or left over 
Resistance 
a plant's natural capacity to withstand disease 
Retasking 
reviewing or reorganising an existing work allocation to obtain a new one, such as retasking of a 
tapping task 
Rhizome 
a thick horizontal underground stem of plants whose buds develop into new plants, e.g. Imperata 
cylindrica 
Rhizomorph 
a root-like structure of certain fungi, consisting of a dense mass of hyphae 
Rhombus 
an oblique-angled parallelogram having four equal sides 
Ringbarking 
removing a strip of bark of a tree by making two circular cuts on the stem 
378 
Ringcutting 
making a circular cut into the bark of a tree the depth of which is just up to the wood to induce 
branching 
Road tracer 
an instrument to plot points of the same level on hill slopes 
Rodent 
any of the relatively small placental mammals that constitute the order Rodentia, having constantly 
growing incisor teeth specialised for gnawing, such as rats, porcupines, etc. 
Rodenticide 
a chemical that kills rodents 
Rogue plant 
a plant of unwanted variety 
Root nodule 
a swelling on the root of leguminous plants that contains bacteria of the genus Rhizobium, capable 
of nitrogen fixation 
Runt 
the smallest and weakest plant in a group 
Saprophyte 
organism which obtains organic matter in solution from dead and decaying tissues of plants or 
animals 
Saturate 
to fill, soak or imbue totally 
Scale bud 
a bud (undeveloped shoot) without the leaf axil 
Scion 
a shoot or twig of a plant used to form a graft 
Sediment 
matter that settles to the bottom of a liquid 
Serum 
a clear watery fluid, especially that exuded by serous membrane 
Sesquioxide 
any of certain oxides whose molecules contain three atoms of 02for every two atoms of Cr 20 3 
Silt 
a fine deposit of mud, clay, etc, especially one in a lake or river 
Skim latex 
the water portion of latex after concentration by centrifugation 
379 
Slag 
the fused material formed during the smelting or refining of metals by combining the flux 
with gangue, impurities in the metal; it usually consists of a mixture of silicates with calcium, 
phosphorus, sulphur, etc. 
Slaked lime 
calcium oxide (lime) in which water has been added; calcium hydroxide 
Sludge 
any deposit or sediment resulting from a process, e.g. centrifugation of latex 
Soil aggregate 
a group of soil particles 
Soil ped 
a unit of soil structure such as an aggregate, crumb, prism, block or granule formed by natural 
process 
Soil series 
a group of soils with the same profile characteristics and formed by a parent material of the same 
geological origin 
Spatial 
of or relating to space; existing or happening in space 
Species 
any of the taxonomic groups into which a genus is divided; the members of which are capable of 
interbreeding 
Spermatozoon 
any of the male reproductive cells released in the semen during ejaculation, consisting of a 
flattened egg-shaped head, a long neck, and a whip like tail by which it moves to fertilise the 
female ovum 
Sphere 
a three-dimensional closed surface such that every point on the surface is equidistant from the 
centre 
Spiral 
one of the several plane curves formed by a point winding about a fixed point at an ever increasing 
distance from it 
Spore 
a reproductive body produced by some protozoans of many plants that develops into a new 
individual 
Spray swath 
the width covered by the liquid output of a sprayer nozzle 
Standardisation 
diluting field latex with water to obtain the same dry rubber content (drc) at each day's 
production 
380 
Static 
not active or moving; stationary 
Stigma 
the terminal part of the ovary at the end of the style, where deposited pollen enters the 
gynoceum 
Stimulant 
a chemical or similar substance that increases physiological activity in a plant or animal 
Stock plant 
a plant, usually seedling, raised for vegetative propagation 
Stock solution 
a concentrated solution, usually for storage, which can be further diluted before use 
Stoichiometric 
concerned with, involving or having the exact proportions for a particular chemical reation 
Straight or single fertiliser 
a fertiliser that contains normally one major nutrient and one or more minor ones 
Strip hectare 
the total area occupied by rubber tree planting rows (usually of 2 m wide x total length of planting 
row) per hectare 
Subsoil 
soil below the top layer 
Susceptible 
prone to disease or pest attack or damage 
Synthesis 
the process of producing a compound by a chemical reaction or a series of reactions, usually 
from simpler or commonly available starting materials 
Systemic herbicide 
a chemical that kills herbs by translocation into the plant systems 
Tailing 
pruning the tap root of a plant in the soil a few days before extracting it for transplanting, this is to 
reduce transplanting shock on the plant 
Tapping cycle or frequency 
refers to how often tapping is done on a rubber tree, e.g. daily, alternate daily, third daily, etc. 
Tapping task 
the number of trees given to a tapper to be completely tapped in a specified time, usually a day; 
each day's tapping allocation 
Tar-acid fungicide 
a chemical that kills fungi, produced by tar obtained from coal 
381 
Tasking 
allocating a work load to be completed in a specified time 
Tentacle 
any of various elongated flexible organs that occur near the mouth in many invertebrates and are 
used for feeding, grasping, etc. 
Terminal 
end, eg. terminal bud 
Terracing 
constructing contour steps along hill slopes 
Texture 
the general structure and disposition of the constituent parts such as soil structure 
Thinning out 
removal of unwanted (runts, diseased or defective) plants in a planted stand to reduce the density, 
to increase space, to enhance growth and to reduce waste 
Thorax 
the part of an insect's body between the head and the abdomen, which bears the wings and the 
legs 
Titration 
a measured amount of one solution is added to a known quantity of another solution until the 
reaction between the two is complete; if the concentration of one solution is known, that of the 
other can be calculated 
Topography 
the surface form of land or region 
Toxic 
poisonous, harmful or deadly 
Translocated herbicide 
a chemical that kills weeds by absorption of the chemical into the plant system through the 
stomata in the leaves 
Transpiration 
loss of water in a plant through the leaves by the action of sunlight 
Trapezium 
a quadrilateral having two parallel sides of unequal length 
Turgid 
swollen, disdented and rigid condition of plant cells, especially during the hours of no sunlight 
Turgor or osmotic pressure 
pressure of the cell contents against the cell wall membrane 
382 
Ultra 
extreme 
Undulating land 
land of uneven surface 
Ventral 
relating to a front part of a body towards the belly or seed 
Vertebrate 
any chordate animal of the sub-phylum Vertebrata, characterised by a bony or cartilaginous 
skeleton and a well-developed brain, such as fishes, amphibians, reptiles, birds and mammals 
Virgin bark 
the bark of the rubber tree which has never been tapped 
Viscera 
the large internal organs of the body collectively, especially those in the abdominal cavity; the 
intestines; guts 
Viscosity 
the extent to which a fluid resists a tendency to flow 
Volatile fatty acids 
organic acids which are byproducts of bacteria digestion of the non-rubber constituents in field 
latex; they are undesirable as they destabilise the latex and cause precoagulation 
Volatile matter 
something that is readily capable of changing from liquid or solid form to a vapour 
Volume/volume 
when a certain liquid formulation having its liquid active ingredient given as the percentage of its 
volume, eg. sulphuric acid 
Vortex 
a whirling mass or motion of liquid, gas, flame, etc., such as the spiraling of water around a 
whirlpool 
Vulcanisation 
the treatment of rubber with sulphur or sulphur compounds under heat and pressure to improve 
its properties 
Water table 
the surface of the water-saturated part of the ground (soil), usually following approximately the 
contours of the overlying land surface 
Weathering 
the physical and chemical breakdown of rocks by the action of temperature and rain 
Weed 
an unwanted plant that competes for nutrients, space and light with the crop 
383 
Weeding 
to remove weeds by physical means, such as hand pulling or manual hoeing or cutting. 
Weight/volume 
for a liquid formulation having a solid active ingredient. 
Weight/weight 
an active ingredient expressed as percentage weight for solid formulations, such as dusts, 
granules or powders that are wettable. 
Wettable powder 
a type of formulation for spraying in which a chemical is mixed with an inert carrier, the product is 
refined and surfactant added so that it turns into a suspension when stirred. 
Whorl 
a radial arrangement of leaf petioles or branches around a stem. 
Wintering 
annual shedding of leaves from plants during the dry period; this is nature's way of conserving 
water in a plant. 
Woody growth 
a hard-stem plant. 
Wound dressing 
a chemical substance which is applied to wounded or injured part of a plant. 
Xylem 
a plant tissue that conducts water and mineral salts from the roots to all other parts, provides 
mechanical support and forms the wood of trees and shrubs. 
Yield 
the return or profit from an investment; the product of labour or crop cultivation, e.g. latex is the 
yield of rubber crop. 
Zygote 
the cell resulting from the union of an ovum and a spermatozoon. 
384 
S Y M B O L S 
Symbols In full 
ADS = Air dried sheet 
Ae = Acid equivalent 
ai = Active ingredient 
AVROS = Algemene Vereniging Rubberplanters' Oostkust Sumatra 
B = Boron 
BPM = Balai Penelitian Medan 
C = Carbon 
Ca = Calcium 
CalCI2 = Calcium chloride 
CaCn2 = Calcium cynamide 
CaC0 3 = Calcium carbonate 
Ca 3(P0 4) 2 = Superphosphate 
Cc = Cubic centimetre (millilitre) 
CH = Chemara 
CH3COOH = Acetic Acid 
CIRP = Christmas Island Rock Phosphate 
CIS = Commonwealth of Independent States 
CI = Chlorine 
Cm2 = Square centimetre 
Cm3 = Cubic centimetre 
C0 2 = Carbon dioxide 
Co(NH2)2 = Urea 
Cr 20 3 = Chromium sesquioxide 
Cu = Copper 
CuS0 4 = Copper sulphate 
Cv = Constant viscosity 
Cwt = Hundredweight 
385 
DOL = Division of Labour 
DPNR = Deproteinised Natural Rubber 
DRC = Dry rubber content 
Eg = Example 
ENR = Epoxidised Natural Rubber 
ERP = Egyptian Rock Phosphate 
Etc = Etcetra 
EU (EEC) = European Union (European Economic Community) 
Fe = Iron 
FELCRA = Federal Land Consolidation and Rehabilitation Authority 
FELDA = Federal Land Development Authority 
FRP = Florida Rock Phosphate 
FTS = Freeze-thaw stabilised 
GDR = German Democratic Republic 
GML = Ground magnesium limestone 
GT = Godang Tapen 
gtt = Grammes per tree per tapping 
H = Hydrogen 
Ha = Hectare 
HA = High ammonia 
H3B03 = Boric acid 
HCHO = Formalin 
H20 = Hydrogen oxide 
HNS = Hydroxylamine neutral sulphate 
IBA = Indole butyric acid 
Imp = Imperial 
IRHD = International Rubber Hardness Denteometer 
IRQPC = International Rubber Quality and Packing Conference 
IRRDB = International Rubber Research and Development Board 
IRSG = International Rubber Study Group 
ISO = International Organisation for Standardisation 
386 
JRP = Jordanian Rock Phosphate 
KCI = Potassium chloride (Muriate of potash) 
Kg = Kilogramme 
Km = Kilometre 
Km2 = Square kilometre 
KMPH/kmph = Kilometres per hour 
K20 = Potassium monoxide 
K2S04 = Potassium magnesium sulphate 
LA = Low ammonia 
LCV = Low constant viscosity 
Lit Litre 
M = Metre 
03 = Ozone 
OENR = Oil Extended Natural Rubber 
OS = Ortet selection 
P = Phosphorus 
PA = Processing aid 
PB = Prang Besar 
PBIG/GG = Prang Besar Isolation Garden/Gough Garden 
PC = Promotional clone 
PCNB = Pentachloronitrobe 
pH = Potential of hydrogen 
PHR/phr = Parts per hundred of rubber 
PM = Padang Meiha 
PNG = Papua New Guinea 
Po = Initial plasticity 
P205 = Phosphorus pentoxide 
PPM/rpm = Part per million 
PR = Proefstation voor Rubber 
PRC = Peoples Republic of China 
PRI = Plasticity retention index 
387 
PVC = Polyvinyl chloride 
RHC = Rubber hydrocarbon 
RISDA = Rubber Industry Smallholders' Development Authority 
RM = Ringgit Malaysia 
RPM = Revolution per minute 
RRIC = Rubber Research Institute of Ceylon(Sri lanka) 
RRII = Rubber Research Institute of India 
RRIM = Rubber Research Institute of Malaysia 
RSS = Ribbed smoked sheet 
SMR = Standard Malaysian Rubber 
SP = Superior or special processing 
SPP = Sodium pentachlorophenate 
TMTD = Tetramethyl-thiuram disulphide 
US = United States (of America ) 
USA = United States of America 
USS = Unsmoked sheet 
V = Volume 
Vr = Viscosity of raw rubber 
V/v = Volume over volume 
W/v = Weight over volume 
W/w = Weight over weight 
ZDC = Zinc diethyldithiocarbamate 
Zn = Zinc 
388 
M E A S U R E M E N T S 
Weight 
10 milligrammes 
10 centigramme 
10 decigrammes 
10 grammes 
10 decagrammes 
10 hectogrammes 
1000 kilogrammes 
10 quintals 
Length 
10 millimetres 
10 centimetres 
10 decimetres 
10 metres 
10 decametres 
10 hectometres 
10 kilometres 
Volume 
10 millilitres 
10 centilitres 
10 decilitres 
10 litres 
10 decalitres 
10 hectolitres 
Area 
100 square millimetres 
100 square centimetres 
100 square decimetres 
100 square metres 
100 square decametres 
1 centigramme 
1 decigramme 
1 gramme 
1 decagramme 
1 hectogramme 
1 kilogramme 
1 tonne 
1 tonne 
1 centimetre 
1 decimetre 
1 metre 
1 decametre 
1 hectometre 
1 kilometre 
1 myriametre 
1 centilitre 
1 decilitre 
1 litre 
1 decalitre 
1 hectolitre 
1 kilolitre 
1 square centimetre 
1 square decimetre 
1 square metre 
1 square decametre 
1 square hectometre 
389 
100 square hectometres = 
100 square kilometres = 
100centiares = 
100 ares = 
100 hectares = 
10000 square metres = 
General and Approximates 
1 litre of water @ 30 °C = 
1 cubic metre of water @ 30 °C = 
1 cubic metre of salt water = 
1 cubic metre of clay soil = 
1 cubic metre of loose soil = 
1 cubic metre of river sand = 
1 tea spoon of liquid = 
1 dessert spoon of liquid = 
1 table spoon of liquid = 
1 condensed milk tin of liquid = 
1 condensed milk tin of mixture, 
compound and dust fertilisers = 
1 condensed milk tin of dalapon 
and light chemical powders = 
1 condensed milk tin of sodium chlorate = 
1 kerosene tin of liquid = 
1 square kilometre 
1 square myriametre 
1 are 
1 hectare 
1 square kilometre 
1 hectre 
996.2145 grammes 
0.001 cubic metre 
996.2145 kilogrammes 
1000 litres 
1014.3597 kilogrammes 
1000 litres 
1996.7712 kilogrammes 
1517.5461 kilogrammes 
1273.9388 kilogrammes 
3.5525 cubic centimetres (millilitres) 
7.105 cubic centimetres (millilitres) 
14.21 cubic centimetres (millilitres) 
284.21 cubic centimetres 
340.194 grammes 
284.21 cubic centimetres 
284.21 cubic centimetres 
20 litres 
Conversion from Metric to Conventional System 
Centimetre = 0.3937 inch 
Centimetre = 0.0328048 foot 
Metre = 39.3701 inches 
Metre = 3.28084 feet 
Metre = 1.09361 yards 
Metre = 0.0497097 chain 
Kilometre = 0.621371 mile 
Gramme = 0.035274 ounce 
Gramme = 0.0264554 tahil 
390 
Kilogramme 2.20462 pounds 
Kilogramme 1.653466 katis 
Kilogramme 0.0196841 hundredweight (Imp) 
Tonne 2204.62 pounds 
Tonne 19.6841 hundredweights (Imp) 
Tonne 22.0473 hundredweights (Us) 
Tonne 16.5347 pikuls 
Tonne 1.10231 tons (US) 
Tonne 0.984203 ton (Imp) 
Square centimetre = 0.155 square inch 
Square centimetre = 0.0010764 square foot 
Square metre = 1549.907 square inches 
Square metre 10.7639 square feet 
Square metre = 1.19599 square yards 
Square metre = 0.002471 square chain 
Square kilometre 0.386102 square mile 
Hectare 2.47105 acres 
Cubic centimetre 0.0610236 cubic inch 
Cubic centimetre 0.00017598 pint(lmp) 
Cubic centimetre = 0.035315 fluid ounce 
Cubic metre 1.30795 cubic yards 
Cubic metre = 219.969 gallons(lmp) 
Litre = 0.035315 cubic foot 
Litre 1.759752 pints(lmp) 
Litre 35.19504 fluid ounces 
Litre 0.219969 gallon(lmp) 
Celsius 5/9 (x °F-32°) 
Conversion from conventional to metric system 
Inch = 2.54 centimetres 
Inch 0.0254 metre 
Foot = 30.48 centimetre 
Foot = 0.3048 metre 
Yard = 0.9144 metre 
Chain = 20.1168 metre 
Mile 1609.34 metre 
Mile = 1.60934 kilogrammes 
Ounce = 28.3495 grammes 
Tahil = 37.7994 gram 
391 
Kati 
Kati 
Pound 
Hundredweight (Imp) 
Hundredweight (Imp) 
Hundredweight (US) 
Pikul 
Pikul 
Ton (US) 
Ton (Imp) 
Square inch 
Square foot 
Square foot 
Square yard 
Square chain 
Square mile 
Acre 
Fluid ounce 
Fluid ounce 
Cubic inch 
Pint (Imp) 
Pint (Imp) 
Gallon (imp) 
Gallon (Imp) 
Cubic foot 
Cubic yard 
Fahrenheit 
604.879 grammes 
0.0604879 kilogramme 
0.45359237 kilogramme 
50.8023 kilogrammes 
0.050823 tonne 
0.045378 tonne 
60.479 kilogrammes 
0.060479 tonne 
0.907185 tonne 
1.01605 tonnes 
6.4516 square centimetres 
929.03 square centimetres 
0.092903 square metre 
0.836127 square metre 
404.686 square metres 
2.58999 square kilometres 
0.404686 hectare 
28.4131 cubic centimetres 
0.0284131 litre 
16.3871 cubic centimetres 
568246 litres 
0.00454609 cubic metre 
0.00454609 cubic centimetre 
4.54609 litres 
28.3168 litres 
0.764555 cubic centimetres 
9/5 (x °c)+32° 
392 
R E F E R E N C E S 
ABDULLAH BIN HASSAN, CHONG.K.M., ISMAIL BIN HUSSEIN, KHOO.S.K., HANG,A.K.,TAN, 
P.H., YEW, F.K. AND LEONG, S.K.(1975) Nursery Techniques for Rubber Plant Propagation. 
Agric. Series Report No 2/75. 
ABERCOMBIE, M., HICKMAN,C J . AND JOHNSON, M.L. (1968) A Dictionary of Biology, pp7-
284.Great Britain: Hunt Bernards Co.Ltd., Aylesbury. 
ABRAHAM, PD. AND ISMAIL BIN HASHIM(1983) Exploitation Procedures for Modern Hevea 
Cultivars. Proc. Rubb. Res. Inst. Malaysia. Plrs.Conf.Kuala Lumpur 1983, 126. 
ABRAHAM, P.D., T.C. P'NG AND E. K. NG (1971), RRIM Ethrel Trials: Progress Report. In: 
Proc. Rubb. Res. Inst. Malaya Plrs' Conf., 1971, Kuala Lumpur: Rubb. Res. Malaya, pp 1 - 31. 
ABRAHAM, P.D., T.C. P'NG, C.K. LEE, S. SIVAKUMARAN, B. MANIKAM AND C.H. YEOH 
(1975). Ethrel Stimulation of Hevea: In: Proc. Inter. Rubb. Conf. Oct. 1975, Vol. II. Kuala 
Lumpur: Rubb. Res. Inst. Malaysia, pp. 347-384. 
ABU BAKAR BIN HAJI AHMAD(1972) Buku Panduan llmu Getah. Bahan tidak terbabit. Kuala 
Lumpur. Institut Penyelidikan Getah Malaysia. 
ABU BAKAR BIN HAJI AHMAD(1974) Buku panduan llmu Getah. Bahan Tidak terbabit. Kuala 
Lumpur. Institut Penyelidikan Getah Malaysia. 
ABU BAKAR BIN AHMAD (1985) Teknologi Getah Asli, pp.1-319. Kuala Lumpur. Institut 
Penyellidikan Getah Malaysia. 
ABU BAKAR BIN HAJI AHMAD DAN ROSLEY BIN ABDULLAH (1994) Teknologi Perladangan 
dan Pemprosesan Getah, pp.1-319.Kuala Lumpur. Institut Penyelidikan Getah Malaysia. 
AHMAD K.M., ZAMERI M., ZAINALA.M., ZAIROSSANI M.N., "Rapid Method for DRC 
Determination" Seminar on Raw Rubber Processing - Issue and Challenges, September 2006. 
AHMAD ZARIN BIN HAJI MAT TASI AND SIVAKUMARAN,S(1994) Periodic Tapping:An 
Approach to Tackle Tapper Shortage. Preprint of Workshop on Exploitation Technologies to 
Overcome Current Labour Problems in the Rubber Industry. Kuala Lumpur 1994. 
ANON, "Kandungan Getah Kering (kgk)", Buletin Getah Asli, Edisi Khas 1999 p. 25. 
CHONG, K. AND SIVAKUMARAN, S. (1994) Performance of Low Frequency Tapping Systems. 
Preprint of workshop on Exploitation Technologies to Overcome Current Labour Problem in the 
Rubber Industry. Kuala Lumpur 1994. 
DEROUET, D., CAURET, L. AND BROSSE, J.C. (2003). New Chemical Compounds for 
Stimulation of Latex Flow and Yield. J. Rub. Res. 6(3), pp. 172 - 188. 
EDGAR, AT (1985) Manual of Rubber Planting, pp.1-705. Kuala Lumpur: Incorporated Society 
of Planters. 
393 
GOMEZ, J.B. (1983). Physiology of Latex (Rubber) Production. Monograph No. 8: Malaysian 
Rubb. Dev. Board. 
HANKS, P.(1979) Collins Dictionary of the English Language, pp.1-1690. Scotland: Collins of 
Landon& Glasgow. 
HILTON ,R.N. AND CHUAN, H.C. (1959) Maladies of Heave in Malaya, pp.1-101. Kuala 
Lumpur: Rubber Research Institute of Malaysia. 
INTERNATIONAL RUBBER STUDY GROUP(1994)Rubber Statistical Bulletin, London, 
December 1994. 
ISMAIL BIN HASHIM, MOHD AKBAR BIN MD SAID AND AHMAD ZARIN BIN MAT TAS1(1989) 
Development of RRIMGUD and RRIMCAP. Proc. Rub. Res. Inst. Rubber Growers' Conf. Kuala 
Lumpur, 369. 
LAU, CM. AND CHIN, RS. (1977) Latex Concentrate Preparation and Testing. RRIM 
Technology Series Report No 4/77. 
LEONG ,S.K.,YOON, P.K. AND P'NG, T.C. (1985) Use of Young Budding for Improved Hevea 
Cultivation. Proc. Int. Rubb. Conf. Kuala Lumpur 1985, pp. 555. 
LEONG, W., LEONG, H.T. AND YOON, P.K.(1976) Some Branch Induction Techniques for 
Young Budding, pp. 1-20 Kuala Lumpur: Rubber Research Institute of Malaysia. 
MALAYSIAN RUBBER BOARD (1998). Revised Rubber Strategy - Key Areas for Action. Kuala 
Lumpur, Malaysian Rubber Board. 
MALAYSIAN RUBBER STATISTICS 2008, Malaysian Rubber Board, Kuala Lumpur. 
MOHD AKBAR MD SAID AND ABD SAMAT MOHD SALLEH (2003). Commercial Adoption 
of Technology with Emphasis on Optimizing Crop Exploitation. Paper presented in: National 
Rubber Conference, Oct. 21 - 22, 2003, Kuala Lumpur: Malaysian Rubber Board. 
MOHD. AKBAR MD SAID, SIVAKUMARAN, S. AND SAMSUDIN ATAN (1998). Once a Week 
Tapping System (1/2S d/6) with Ethephon Stimulation for Young Mature Rubber. Paper 
presented in LITS Seminar 1998, August 10,1998, Sg. Buloh, Selangor, Malaysia. Malaysian 
Rubber Board. 
MOHD AKBAR MD SAID AND MEGA ARJUNA ABANG (2002). Exploitation Technology -
Advances and Challenges Facing the NR Industry of Malaysia. IRRDB Workshop on Breeding, 
Agro-Forestry and Socio-Economy. Kuala Lumpur, Malaysia. 
M.R. FATIMAH RUBAIZAH, S ANITHA, M.N. ZAIROSSANI, Teknologi Terkini Penyediaan, 
Penganalisaan dan Pemprosesan Getah Mentah untuk Industri Getah, Seminar BPP, Disember 
2006. 
NG, A.P., HO, C.Y., SULTAN, M.O., OOI, C.B., LEW, H.L. AND YOON..P.K. (1981) Influence of 
Six Rootstock on Growth and Yield of Six Scion Clone of Hevea Brasiliensis. Proc. Rubb. Res. 
Inst. Malaysia Plrs'. Conf. Kuala Lumpur 1981, pp. 134. 
394 
PAARDEKOOPER,EC(1976) Clone of Hevea brasiliensis of Commercial Interest in Malaya. 
Planting Manual No 11/ 65. Kuala Lumpur:Rubber Research Institute of Malaysia. 
PAKIATHAN, S.W ., WONG,. T.K. AND HAFSAH JAAFAR(1979) Use of IBA on Budded Stumps 
to Aid Earlier Root Initiation and Growth. Proc. Rubb. Res. Inst, Malaysia Plrs'. Conf, Kuala 
Lumpur 1979, pp. 273. 
PANTAI MAJU SDN BHD(1995) Malaysia Agricultural Directory & Index 1995/1996, pp. 232-
234. Kuala Lumpur: Pantai Maju Sdn Bhd. 
RAMA RAO, P.S., JOHN, C.K., NG, C.S., SMITH, M.G. AND ROBERT, C.F. (1976) Commercial 
Exploitation of TMTD-ZnO Preservative System. Proc. Rubb. Res. Inst. Malaysia Plrs'. Conf. 
Kuala Lumpur 1976, pp. 324. 
RAO, B.S. (1975) Maladies of Hevea in Malaysia, pp. 1-108.Kuala Lumpur: Rubber Research 
Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1953-1992) Planters' Bulletin Nos 4-217. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1991) Revisions to Standard Malaysia 
Rubber Scheme's Bulletin No 11, pp.1-8. Kuala Lumpur: Rubber Research Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1977) Soils Under Hevea and Their 
Management in Peninsular Malaysia, (Pushparajah, E and Amin, LL ed), pp.1-188. Kuala 
Lumpur: Rubber Research Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1980) Training Manual on Crop Protection 
and Weed Control in Rubber Plantation, pp. 1-203. Kuala Lumpur: Rubber Research Institute of 
Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1982) Training Manual on Natural Rubber 
Processing, pp.1-232. Kuala Lumpur: Rubber Research Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1982) Training Manual on Rubber Planting 
and Nursery Techniques, pp.1-232. Kuala Lumpur: Rubber Research Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA (1981) Training Manual on Soils, 
Management of Soils and Nutrition of Hevea, pp.1-203. Kuala Lumpur: Rubber Research 
Institute of Malaysia. 
RUBBER RESEARCH INSTITUTE OF MALAYSIA(1980) Training Manual on Tapping, Tapping 
System and Stimulation of Hevea.pp. 1-287. Kuala Lumpur: Rubber Research Institute of 
Malaysia. 
SIARAN PEKEBUN, "Cara Menentukan Kandungan Getah Kering". Mac 1974, Bil. 53 p. 8-10. 
SIVAKUMARAN, S., S.W. PAKIANATHAN AND P.D. ABRAHAM (1982). Long-term Ethephon 
Stimulation. II. Effect of Continuous Ethephon Stimulation with Low Frequency Tapping 
Systems. J. Rubb. Res. Inst. Malaysia, 30: pp. 174-196. 
SHORROCKS.VM (1964) Mineral Deficiencies in Hevea and Associated Cover Plants, pp.1-76. 
Kuala Lumpur: Rubber Research Institute of Malaysia. 
395 
SOONG, N.K., HARID A.S.G, YEOH, C.S..AND TAN, P.H. (1980) Soil Erosion and Conservation 
in Peninsular Malaysia , pp.1-69. Kuala Lumpur: Rubber Research Institute of Malaysia. 
WILLIAM GEDDIE (1959) Chambers Twentieth Century Dictionary, pp. 1-1987,Great Britain: 
W&R Chambers Ltd. London & Edinburgh. 
WING LAND YOON, P.K. (1983) Effect of Low and Controlled Pruning on Growth and Yield of 
Hevea Brasiliensis. Proc. Rubb. Res. Inst. Malaysia Plrs'. Conf. Kuala Lumpur 1983,261. 
YAHYA ABD KARIM (2008) Optimising the use of Nutrients through Fertilisation. Sains & 
Teknologi LGM. Jilid 3, Buletin Bil. 1/2008, pp8. 
YOON, P.K., LEONG, S.K. AND OOI, C.B.(1985) The Value of Deep Planting in Hevea 
Cultivation. Proc. Int. Rubb. Conf. Kuala Lumpur 1985, pp. 578. 
YOON, P.K., AND OOI, C.B.(1978) Prospect of Deep Planting of Propagated of Hevea. Proc. 
IRRDB Symp. Kuala Lumpur 1978, pp. 1. 
2AMERI M., "Status and Quality of Raw Materials in Malaysia." Seminar on Raw Rubber 
Processing-Issue and Challenges", September 2006. 
396 
I N D E X 
Accelerated erosion, 82, 83 
Achatina fulica, 237 
Acheta testacea, 220 
Adoretus compressus, 235 
Adoxophyes privatana, 228 
Advance-aged planting material, 51, 63, 213 
Albarol white oil, 223 
Alfa Laval centrifuge machine, 358 
2,4-D Amine, 178 
Ammonia, 289, 318, 319, 320 
Ammonium alginate, 359 
Ammonium laurate, 357 
Amsacta lactinea, 228 
Anchorage, 22 
Anther 21, 24 
Anthracnose, 139, 210 
Antracol, 206, 209 
Approach-grafting,25, 48 
Arboricide, 104, 106 
Atractomorpha spp., 220 
Assault 100A, 178 
Assystasia gangetica, 178 
Aspidiouts destructor, 223 
Atom, 241,245 
Avenue system, 43 
Axillary bud, 21,57 
Bale coating solution, 351 
Basal fertiliser, 52,122 
Bayleton 25WP, 188 
Benlate, 199,208 
Benzyladenine, 170 
Biological weed control, 184 
Bipolaris heveae, 209 
Blanket hectare, 177 
Blind contour, 118, 119 
Block rubber, 315, 316, 318, 319, 322, 352, 355, 361 
Bordeaux mixture, 194 
Boric acid, 319, 320, 358 
Brachytryptes protentosus, 220 
Brown bast, 192, 202, 203, 204, 303 
Budded stump, 52, 54, 55, 56, 59, 60, 61, 66, 67, 123 
Budding panel, 25, 26, 28 
Budgrafting, 25 
Budpatch, 25, 26, 27, 28, 160, 193 
Budstick, 25, 26, 27, 52, 54, 57, 58 
Bunding, 81, 83, 85 
Bush nursery, 57 
Calixin collar protectant, 188 
397 
Callosciurus caniceps, 244 
Callosciurus notatus, 244 
Calopogonium caeivleum, 90, 92, 93 
Calopogonium mucunoides, 90 
Callus, 25, 28 
Cambium, 22, 198, 201, 215, 250, 251, 253, 261, 313 
Carbendazim, 210 
Classia obtusifolia, 90 
Centrosema pubescens, 90, 92, 93 
Ceratocystis fimbriata, 199 
Curves unicolar, 118 
Chemical drenching, 188, 189 
Chromolaena odorata, 177, 178, 179 
Clania variegate, 228 
Clidemia hirta, 177, 178 
Chlorophyll, 142, 165 
Cleft-grafting, 25, 48 
Clitoria rubigonosa, 90 
Clonal seed, 43, 44, 45, 47, 48, 56 
Collar inspection, 187 
Collar protectant, 187, 188 
Colletotrichum gloeosporioides, 193, 204, 205 
Compound fertiliser, 95, 144, 146, 147, 148, 149 
Compounding process, 356 
Composite preservative system, 319 
Contact Adhesive, 286, 287 
Controlled droplet applicator (CDA), 208 
Controlled pruning, 158,159, 160,164,165 
Coptotermes curvignathus, 222 
Core stump, 52, 54, 56, 63, 65, 123 
Corky bark, 250 
Corrective pruning, 159, 160, 161 
Corticium salmonicolor, 194 
Corynespora cassiicola, 208 
Cotyledon, 50, 240, 241 
Crematopsyche pendula, 228 
Creosote, 104,187,197 
Crotalaria anagroides, 90, 91 
Cuttings, 25, 83, 350, 351 
DaconilF500, 194 
Deep planting, 123, 126, 315 
Defects in RSS, 342 
Depth of tapping, 250, 251, 300, 313 
Desmodium groides, 90 
Desmodium ovalifolium, 90 
Dicotyledon, 48 
Dicranonopteris linearis, 177, 178 
Difolatan, 198, 199, 200, 201 
Dinothrips sumatrensis, 227 
Dipterex SP, 95, 228 
Discriminatory fertiliser application, 141 
Dithane, M-45, 61, 209 
398 
DOE, 103, 106 
DOL system, 308 
Dormant bud, 21 
Double-hedge planting, 114 
Dry rubber content, 23, 251, 322 
Dursban EC, 222, 230 
Dysmicoccus spp, 226 
Eleucine indica, 179 
Embryo, 21 
Epical bud, 21, 167 
Epilachna indica, 234 
Eulica similaris, 237 
Euphorbiaceae, 1 
Euproctis subnotata, 228 
Exopholis hypoleuca, 230 
Extrusive rock, 69 
Fanjet nozzle, 180 
FELCRA, 17 
FELDA, 17, 246 
Fertilisation, 21,24 
Ferrisiana virgata, 226 
Fire breaker, 103 
Floodjet nozzle, 180 
Formalin,322, 323 
Formic acid, 324, 327, 335 
Fusarium solani, 201 
Fusicoccum sp., 210 
Gadon, 104,106,177, 178 
Ganoderma philippi, 185 
Geological erosion, 82 
Germination bed, 50, 51 
Goug, 253, 254, 298 
Green budding, 25, 26, 28 
Ground-water laterites, 71 
Gully erosion, 83, 84 
Hand pollination, 21, 24, 29 
Hard bast, 250 
Hedge planting, 135 
Height of tapping, 248, 249 
Heliothrips haemorrhoidalis, 227 
Hemitarsonemus latus, 236 
Hemibedesia cyanophylli, 223 
Hemibedesia palmae, 223 
Hepomeces leporinus, 233 
Hevea brasiliensis, 1 
High budding, 52, 54, 56, 63, 64 
High frequency tapping, 304 
Hinder, 239 
Hybrid rock, 69 
Hydroxylamine neutral sulphate, 319, 352, 355 
Hyposidra talaca, 228 
Hystrix brachyura, 243 
399 
IBA root stimulant, 59 
Icerya spp., 226 
Imperata cylindrica, 89, 91, 127, 128, 174, 175, 177, 178, 179 
Inflorescence, 21 
Inorganic fertiliser, 144 
Intrusive rock, 69 
Iron mottles, 72 
IRQPC, 345 
Ischaemum muticum, 179 
Isolation belt, 44 
Isolation trench, 187, 189, 190 
Jebong knife, 253 
Lachnosterna (holotrichia) bidentata, 230 
LA-BA, 355 
Lamella,142 
Landslide, 83, 84 
Large-scale planting, 2, 47, 247 
LA-SPP, 355 
Latent, 21 
Laterisation, 71 
Latex centrifugation, 357 
Latex concentrate, 7, 318, 321, 355, 357, 358, 360, 361 
Latosolisation, 71 
LA-TZ, 354 
Lauric acid, 321, 357, 358, 360 
LA-ZDC, 357 
Leader Branch,160, 161 
Leaf folding, 168 
Leguminoseae, 89 
Legume purification, 175 
Lenticels, 22, 211 
Lepidosaphes cocculi, 223 
Lepidiota stigma, 230 
Leucaena glauca, 90 
Leucopholis nummicudens, 230 
Leucopholis rorida, 230 
Leucopholis tristis, 230 
Lindane 20, 220 
Loranthus globasus, 195 
Loranthus pentandrus, 195 
Lorsban 70EC, 230 
Macaca irius, 246 
Macaca nemestrina, 246 
Malathion LV, 220 
MAPA, 305 
Mariaella dussumieri, 237 
MARDEC, 339 
Masterbatch, 325 
Medulla, 21 
Medullary rays, 22, 250 
Melastoma malabathricum, 177, 178, 179 
Meniscus, 326 
400 
Meristematic tissues, 142 
Metamorphic rock, 69 
Methyl-methacrylate, 315, 361 
Mikania micrantha, 89, 174, 177, 179 
Mimosa invisa, 90 
Minor elements, 149 
Mitac, 214, 227, 236 
Mitosis, 22 
Mixture fertiliser, 146, 147, 155 
Mods undata, 228 
Moderate-scale planting, 47 
Modified latex concentrates, 360 
Moghania macrophylla, 90, 235 
Molecular chain, 357 
Monoclone, 45 
Monel-metal gauze strainer, 331, 338, 352, 357 
Motoray, 254 
Mottling layer, 107 
MST, 353 
Mucuna cochinchinensis, 90, 92, 93 
Mulching, 83, 86,123, 127, 128 
Muntiacus muntjac, 239 
Nacoleia (lamprosema) diemenalis, 228 
Necrosis, 142, 192,198, 201 
New planting, 97, 98, 99, 100, 101, 103 
Nicking, 28 
Nodostoma aeineipenne, 235 
Noxious weeds, 176,177, 178 
NUPW, 302 
Nutrient cycle, 156, 157 
Nutrient deficiency, 142, 144 
Nutrients, 73, 74, 81, 82, 89, 90, 91, 99, 139, 141, 142, 145, 146, 147, 148, 149, 156, 173 
Nutritional value, 149 
Oidium heveae, 204 
Oleic acid, 356 
Organic fertiliser, 86,144 
Orgyia turbata, 228 
Orthene 75S, 220 
Osmosis, 22 
Ovary, 21 
Oxidation, 70, 71, 72, 336, 347 
Pagria signata, 235 
Paraquat, 95 
Parent materials, 69, 70 
Padatoria proteus, 223 
Parmarion martensi, 237 
Penconazole, 210 
Pennisetum polystachyion, 179 
Perennial crops, 18, 112, 131, 185 
Periodic tapping, 305, 310 
Petiole, 21, 28, 57, 205, 207, 215, 227 
Petiolule, 21 
401 
Phaseolus pubescens, 90 
Phenacaspis dilatata, 223 
Retasking, 301, 303, 302, 314 
Ridley HN, 2, 247 
Ridomil 25WP, 200 
Rhizobium compost, 94, 95 
Rhizomys pruinosus, 242 
Rhizomys sumatrensis, 242 
Rigidoporous lignosus, 185 
RISDA, 4, 17, 97 
Rollmark, 252, 258, 298 
Root/seed-grafting, 25, 48 
Roundup, 177, 178 
RRIMCAP, 261 
RRIMCUP, 261 
RSS, 315, 316, 318, 322, 343, 345 346, 347, 348, 349, 350, 351, 352, 355, 356 
RSS cuttings, 352 
RSS specifications, 349 
Rubber consumption, 2, 8 
Rubber production, 2, 3, 6, 7, 12,13, 14, 18, 270, 315, 322, 338, 352, 357,361 
Runts, 57, 158 
Saissetia nigra, 223 
Sericothrips dorsalis, 227 
Serum rubber, 360 
Sevin 85S, 95, 228, 234, 235 
Sheeting battery, 336 
Shell collar protectant, 118 
Skim latex, 316, 357, 358, 361 
Slope of tapping cut, 246, 247, 257 
Slow release fertiliser, 61, 62, 149 
SMR, 315, 352 
SMR specifications, 356 
Sodium hydroxide, 321 
Sodium metabisulphite, 352 
Sodium salicylate, 360 
Sodium sulphite, 318, 319, 327, 347 
Solar-powered smokehouse, 344 
Sphaerostilbe repens, 192, 211 
Spray swath, 180,181 
Square Planting, 116 
Standardisation of latex, 322 
Starane, 177, 178 
Stedfast, 222, 230 
Stenocatantops splendens, 220 
Stenochlaena palustris, 179 
Photosynthesis, 22,142, 165 
Phytophthora botryosa, 207 
Phytophthora palmivora, 200 
Phytoscapus leporinus, 233 
Pinnaspis aspidistrae, 223 
Pinnaspis theae, 223 
Placement of fertiliser, 150 
402 
Planting density, 43, 88, 114, 115, 301 
Plumule, 48, 50 
Podzolic process, 72 
Poria hypobrunnea, 192 
Poisoned baits, 237 
Pollen, 21,24,44 
Pollination, 21, 24, 29, 45, 47, 48, 49 
Polyclone area, 45 
Polymerised, 361 
Potassium hydroxide, 359 
Precipitation, 180 
Precoagulation, 266, 317, 319 
Presbytis cristatus, 246 
Presbytis melalopos, 246 
Presbytis obscurus, 246 
Prochloraz, 210 
Prodenia litura, 228 
Propagation, 24, 25, 48 
Prostrate, 89 
Psipholis vestita, 230 
Pueraria phaseoloides, 90, 91, 92, 93, 235 
Pulvinaria maxima, 223 
Quincunx planting, 115 
Rainguard, 255 
Rastrococcus iceryoides, 226 
Rattus argentiventer, 241 
Raff us jalorensis, 241 
Replacement, 18, 24, 126, 157, 158, 171, 315 
Replanting, 4,12, 15, 18, 97, 98, 99, 104, 105, 106, 155, 187, 315 
Straight fertiliser, 145, 146 
Strip hectare, 177 
Stylosanthes gracilis, 90 
Subulina octona, 237 
Sulphuric acid, 359, 361 
Surface run-off, 83, 86 
Sus barbatus, 240 
Sus scrota, 240 
Systemic herbicide, 176 
Tailing, 59, 63 
Tamaron, 220, 233 
Tapping census, 171, 256, 257 
Tapping task, 136, 249, 301, 302, 303 
Task census, 314 
Tasking, 301, 302, 303 
Tephrosia Candida, 90, 91 
Terracing, 81, 83, 85, 87, 98, 99, 100, 101, 102, 111 
Thickness of tapping, 252, 253, 313 
Thosea sinensis, 228 
Tilling, 52, 86, 98, 99, 102 
Tiracola Plagiata, 228 
Tissue culture, 25 
Titration, 335, 352 
403 
TMTD, 289, 321 
Tragulus javanicus, 239 
Tragulus napu, 239 
Triangular planting, 117 
Trichlopyr, 104, 106 
Triple-hedge planting, 114 
Turgor pressure, 249 
Ultra low frequency, 273, 303 
Ultra low volume (ULV), 220 
Underbrushing, 98, 100, 103, 104 
USS, 315, 317, 327, 335, 337, 338, 340, 341, 343, 345, 346, 347, 352, 355, 356 
Ustulina deusta, 192, 196 
Vaginula bleekerie, 237 
Valanga nigricornis, 220 
Vegetative propagation, 25 
VelparK-51, 95 
Vulcanisation, 1, 247, 356 
Vultamol, 312 
Weathering, 69, 70, 71, 72, 73, 122 
Wickham's collection, 1,2 
Wind-rows, 103, 105 
Wintering, 21, 23, 31, 33,156,195, 204, 214, 236, 277, 289, 300 
Wound dressing, 63, 65,164,187,192,193, 195, 196, 214, 216, 217, 218, 219, 220 
Xenocatantops humilis, 220 
Xestina striata, 237 
Young Budding, 25, 26, 28, 52, 54, 56, 59, 62, 63, 123, 126 
ZnO, 289, 321 
404