UNIVERSITI PUTRA MALAYSIA

EFFECTS OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON THE GROWTH, YIELD AND QUALITY OF COCOA (Theobroma

cacao L.)

 

 

 

 

 

 

 

 

 

NOORDIANA NORDIN

T FP 2007 9

 

EFFECTS OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON THE GROWTH, YIELD AND QUALITY OF COCOA (Theobroma cacao L.)

By

NOORDIANA NORDIN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirement for the Degree of Master of Science

January 2007

EFFECTS OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON THE GROWTH, YIELD AND QUALITY OF COCOA (Theobroma cacao L.)

NOORDIANA NORDIN

MASTER OF SCIENCE UNIVERSITI PUTRA MALAYSIA

2007

DEDICATION

To beloved Abah and Mak

Tn. Haji Nordin bin Mohamed Pn. Hajjah Hasnah binti Ahmad

To my soul mate

Abdul Rahman bin Mohamed

And my little prince

Ammar Hasif bin Abdul Rahman

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

EFFECTS OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON THE GROWTH, YIELD AND QUALITY OF COCOA (Theobroma cacao L.)

By

NOORDIANA NORDIN

January 2007

Chairman : Associate Professor Syed Omar Syed Rastan, PhD

Faculty : Agriculture

Malaysian cocoa industries are facing many problems when cocoa in the country is

grown on problem soils such as Ultisols and Oxisols. These soils are generally acidic,

low in basic cations and also low in soil cation exchange capacity. Poor cocoa yield

that was far behind the targeted yield of 1.5 tonnes contribute to reducing in

Malaysian cocoa export. A combination of chemical and organic fertilizers have been

shown to maintained the physical, chemical and biological of soil despite maximizing

continuous production. Foliar fertilizer reduces the imbalance nutrients condition

during critical growing stages. The general objective of this study was to evaluate the

effect of different types of fertilizers on the cocoa growth production and the quality

of cocoa beans. Thus, the specific objectives of this study were to see the effects of

fertilizer treatments (organic-based and foliar fertilizers) on (i) soil fertility

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improvement; (ii) the growth of (matured tree and seedlings) and (iii) yield and beans

quality of cocoa grown on Segamat Series. A field experiment was undertook to

study the effects of organic-based and foliar fertilizers on the soil fertility

improvement, the growth, yield and beans quality of cocoa grown on Segamat series.

Experimental plots were prepared in Malaysian Cocoa Board (MCB) Experimental

Farm with five treatments and four replications. The number of pods (successful

cherelles) was recorded every month, starting 2 months after treatments. Total

number of harvested mature pods was recorded from October 2004 until June 2005.

The potential calculated yield was then estimated using the collected data of number

of pods (successful cherelles) and harvested pods. Five pods were sampled out from

each plot to determine pod and bean quality indicated by dry weight of husk, length

and diameter of pods, weight of harvested pods, average number of beans/pod, single

dry bean weight and pod index. A pot experiment was conducted under glasshouse

conditions using cocoa seedlings of clone KKM 22 and PBC 130 grown in Segamat

Series soil with five treatments. The experiment was conducted to determine the

effect of organic-based and foliar fertilizers (as measured by plant height, stem

diameter, and weight of root and top) on the growth of cocoa seedlings. The

experiment was conducted for 20 weeks starting in August 2005 until January 2006.

Root:shoot ratio and plant height showed no significant response to treatments except

the stem diameter, root biomass and shoot (plant top) dry weight. Results showed

that application of fertilizers gave no significant difference on the growth, yield or

quality of cocoa. Therefore, further soil and leaf analysis had been carried out to

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identify the actual problem of yield limitation by determining the concentration of

macro- and micronutrients. It was discovered that manganese concentrations in soil

and leaf samples for field experiment were 3-fold higher than the adequate range,

possibly resulting in manganese toxicity, therefore cocoa was not grown on good soil.

Manganese toxicity has been found out to be the possible reason of cocoa yield and

quality limitation. The Segamat series contains mineral such as pyroxene which

contributes to Mn. Initial status of Segamat series soil has indicated that Mn

concentration was 113 – 150 mg/kg, which were beyond the adequate range of 20 –

40 mg/kg. An addition of Mn through fertilizer application has made the problem

worst. It is recommended that enough lime should be applied to the soil since the

present liming program (500 g/plant or 0.5 – 1 tan/ha/year, broadcast once a year) has

indicated insufficient to increase the soil pH to an adequate range of 5.5 – 7.0 in order

to obtain better yield and quality of cocoa grown on Segamat series soil.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

KESAN BAJA BERUNSUR ORGANIK DAN BAJA DEDAUN KE ATAS PERTUMBUHAN, HASIL DAN KUALITI KOKO (Theobroma cacao L.)

Oleh

NOORDIANA NORDIN

Januari 2007

Pengerusi : Profesor Madya Syed Omar Syed Rastan, PhD

Fakulti : Pertanian

Industri koko Malaysia sedang berhadapan dengan masalah apabila cocoa di negara

ini ditanam di atas tanah yang bermasalah seperti Ultisols dan Oxisols. Tanah ini

umumnya berasid, kurang kation bes dan juga kadar pertukaran kation yang rendah.

Hasil koko yang rendah iaitu di belakang hasil sasaran sebanyak 1.5 tan turut

menyumbang kepada pengurangan eksport koko Malaysia. Gabungan baja kimia dan

organik telah menunjukkan pengekalan keadaan fizikal, kimia dan biologi tanah

walaupun pengeluaran maksimum secara berterusan. Baja dedaun mengurangkan

keadaan nutrien yang tidak seimbang sewaktu tahap kritikal proses pertumbuhan.

Objektif umum kajian ini adalah untuk menilai kesan baja yang berbeza jenis ke atas

pertumbuhan, hasil dan kualiti koko. Seterusnya, objektif khusus kajian ini adalah

untuk melihat kesan rawatan baja (baja berunsur organik dan baja dedaun) ke atas (i)

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peningkatan kesuburan tanah; (ii) pertumbuhan (pokok matang dan anak pokok) dan

(iii) hasil dan kualiti biji koko yang ditanam pada tanah Segamat. Eksperimen

lapangan telah dijalankan untuk mengkaji kesan baja berunsur organik dan baja

dedaun terhadap kejayaan perkembangan putik koko, hasil dan kualiti koko. Plot

eksperimen telah disediakan di Ladang Percubaan Lembaga Koko Malaysia (LKM)

dengan lima rawatan dan 4 replikasi. Bilangan buah (putik koko yang tidak layu)

direkodkan pada setiap bulan, mulai 2 bulan selepas rawatan bermula. Jumlah

keseluruhan buah koko matang yang dituai direkodkan mulai Oktober 2004 sehingga

Jun 2005. Potensi hasil dikira dengan menganggarkan data terkumpul daripada

bilangan buah (putik koko yang tidak layu) dan buah koko matang yang dituai. Lima

biji buah koko disampel dari setiap plot untuk mengkaji kualiti buah dan biji koko

seperti berat kering kulit koko, panjang dan ukur lilit buah koko, berat buah koko

matang, purata bilangan biji/buah koko, berat kering biji koko dan indeks buah koko.

Eksperimen berpasu telah dijalankan dalam rumah kaca menggunakan anak pokok

koko klon KKM 22 dan PBC 130 yang ditanam dalam tanah siri Segamat dengan

lima rawatan. Eksperimen dijalankan untuk mengkaji kesan baja organik dan baja

dedaun (dengan mengukur tinggi pokok, ukur lilit batang, dan berat akar dan

bahagian atas pokok) ke atas pertumbuhan anak pokok koko. Eksperimen telah

dijalankan selama 20 minggu bermula Ogos 2005 hingga Januari 2006. Nisbah akar:

pucuk dan tinggi pokok tidak memberikan tindakbalas bererti terhadap rawatan

kecuali ukur lilit batang, berat akar dan berat kering bahagian atas pokok. Keputusan

menunjukkan penggunaan baja-baja tidak memberi sebarang perbezaan bererti

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samada terhadap hasil mahupun kualiti koko. Oleh sebab itu, analisis sampel daun

dan tanah yang selanjutnya telah dijalankan untuk mengenalpasti masalah sebenar

hasil yang terhad dengan mengkaji kepekatan makro- dan mikronutrien. Didapati

bahawa kepekatan mangan di dalam sampel daun dan tanah adalah 3 kali ganda lebih

tinggi daripada julat yang memadai, berkemungkinan menyebabkan keracunan

mangan, oleh yang demikian koko tidak ditanam di atas tanah yang baik. Keracunan

mangan telah dikenalpasti sebagai punca yang menghadkan hasil dan kualiti koko.

Tanah Segamat mengandungi mineral seperti pyroxene yang menyumbang kepada

pembentukan mangan. Status tanah Segamat sebelum kajian bermula menunjukkan

bahawa kepekatan managan adalah 113 – 150 mg/kg, yang mana melebihi julat yang

berpatutan iaitu 20 – 40 mg/kg. Penambahan mangan melalui baja telah menjadikan

masalah ini semakin buruk. Adalah disyorkan bahawa kapur yang mencukupi diberi

kepada tanah siri ini memandangkan program pengapuran yang sedia ada (500

g/pokok atau 0.5 – 1 tan/ha/tahun, ditabur sekali setahun) telah menunjukkan kadar

yang belum mencukupi untuk menaikkan pH tanah kepada julat yang bersesuaian

iaitu 5.5 – 7.0 untuk mendapat hasil dan kualiti yang lebih baik bagi koko yang

ditanam di tanah Segamat.

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ACKNOWLEDGEMENTS

First and foremost, I wish to give special thanks and express my gratitude to my

supervisor, Associate Professor Dr. Syed Omar Syed Rastan, and my supervisory

committee, Professor Dr. Shamsuddin Jusop, without whom this Master’s thesis

would not have been made possible. They both introduced me into the field of soil

science and fertility, and all their constructive comments, criticisms and suggestions

have been of great help throughout this research.

I would like to express my sincere thanks to Mr. Nik Aziz Nik Mat, a member of my

master research committee, for his constructive comments in my works and guidance

in the experimental work. This research was made possible with the collaboration of

the Malaysian Cocoa Board (MCB). Thanks are also due to staff and management of

MCB Experimental Farm, Jengka in providing the cocoa trees, equipments required

for the experiment and also labours for the tough work in the field. I would also like

to thanks all staff of Land Mangement Department and particularly; Mr. Alias, Mr.

Mahyudeen, Mr. Jamil and Mr. Zainuddin for their assistance and cooperation.

Financial support during my study was provided by the Ministry of Science,

Technology and Innovation (MOSTI) for the financial support IRPA project number

01-02-04-0503-EA001and the South East Asia Research Centre for Agriculture

(SEAMEO SEARCA) scholarship, for which I am sincerely grateful. I would also

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like to extend my sincere thanks to Diversatech (M) Sdn. Bhd. in providing the

fertilizers required for the experiment.

My deepest gratitude is for my parent, Hj. Nordin Mohamed and Hjh. Hasnah

Ahmad, my husband, Abdul Rahman Mohamad, for consistently providing an

inspiring and conducive atmosphere. There were times when quiting seemed to be

the best options, but their love made me carry on. My thanks to all my colleagues for

their kind help. Finally, I would like to extend my deepest appreciation to all who

have contributed in one way or another to the success of this thesis.

And above all, my thank are due to Allah, The Almighty, The Merciful, The

Benevolent. His grace alone brings succour.

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I certify that an Examination Committee has met on 26th January 2007 to conduct the final examination of Noordiana Binti Nordin on her Master of Science thesis entitled “Effects of organic-based and foliar fertilizers on the growth, yield and quality of cocoa (Theobroma cacao L.)” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows: Hamdan Jol, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman) Ahmad Husni Mohd. Hanif, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner) Aminuddin Hussin, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner)

Mohd. Aris Junus, PhD Professor Malaysian Agricultural Research and Development Institute MARDI (External Examiner)

________________________________ HASANAH MOHD. GHAZALI, PhD Professor/Deputy Dean School of Graduate Studies Universiti Putra Malaysia

Date: 27 APRIL 2007

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee are as follows:

Syed Omar Syed Rastan, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman)

Shamshuddin Jusop, PhD Professor Faculty of Agriculture Universiti Putra Malaysia (Member)

En. Nik Aziz Nik Mat Senior Research Officer Malaysian Cocoa Board Jengka, Pahang (Member)

______________________

AINI IDERIS, PhD Professor/Dean School of Graduate Studies Universiti Putra Malaysia Date: 10 MAY 2007

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DECLARATION

I hereby declare that the thesis is based on my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.

_____________________

NOORDIANA NORDIN

Date: 20 March 2007

xiii

TABLE OF CONTENTS Page DEDICATION ii ABSTRACT iii ABSTRAK vi ACKNOWLEDGEMENTS ix APPROVAL xi DECLARATION xiii LIST OF TABLES xvi LIST OF FIGURES xvii CHAPTER

1 INTRODUCTION 1 2 LITERATURE REVIEW 2.0 World cocoa industry 9 2.1 Factors affecting cocoa production 12

2.1.1 Yield 12 2.1.2 Cocoa price 12 2.1.3 Input cost 13 2.1.4 Government support 13 2.1.5 Alternative crops 14 2.1.6 Tree stock characteristics 14 2.1.7 Environmental influences 14

2.2 Malaysia cocoa industry 15 2.2.1 Yield and production cost 17

2.2.2 Quality of cocoa 18 2.3 The botany of cocoa 18 2.3.1 Types and clones 18 2.3.2 Plant characteristics 20 2.3.3 Root system 21 2.3.4 Inflorescence, pollination and fruiting 22 2.4 Commercial planting of cocoa 24 2.4.1 Land and climate suitability 24 2.4.2 Planting system of cocoa 25 2.4.3 Soil fertility improvement and

fertilizer management 26 2.4.4 Harvesting pods and beans fermentation process 30

3 EFFECTS OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON POD DEVELOPMENT, YIELD AND QUALITY OF COCOA

3.0 Introduction 33 3.1 Objectives 37

xiv

3.2 Materials and methods 37 3.2.1 Background of experimental site 37 3.2.2 Field sampling of soil and plant tissues 41 3.2.3 Soil and plant samples preparation for analysis 41 3.2.4 Physical and chemical analysis of soil samples 42 3.2.5 Plant tissue analysis 46 3.2.6 Pods production 48 3.2.7 Yield estimation 49 3.2.8 Pod and bean quality determination 50 3.2.9 Statistical Analysis 51

3.3 Results and discussion 51 3.3.1 Soil properties of experimental site 51 3.3.2 Plant tissue nutrient status 53 3.3.3 Effects of fertilizer treatments on soil fertility 54 3.3.4 Effects of fertilizer treatments on plant

nutrient status 56 3.3.5 Fertilizer treatment effects on pods production 60 3.3.6 Fertilizer treatment effects on yield 60

3.3.7 Fertilizer treatment effects on pod and bean quality 63

4 APPLICATION OF ORGANIC-BASED AND FOLIAR FERTILIZERS ON YOUNG COCOA SEEDLINGS

4.0 Introduction 65 4.1 Objective 66 4.2 Materials and methods 67

4.2.1 Measurement of plant height 71 4.2.2 Measurement of stem girth 72 4.2.3 Determination of root and shoot (plant top)

dry weight 72 and root:shoot ratio

4.2.4 Sample preparation 72 4.2.5 Soil chemical analysis 73 4.2.6 Tissue analysis 73 4.2.7 Statistical Analysis 73

4.3 Results and discussion 74 4.3.1 Plant height 74

4.3.2 Stem girth 74 4.3.3 Root, shoot (plant top) dry weight and

root:shoot ratio 74

5 CONCLUSIONS 85 REFERENCES 90 APPENDICES 99 BIODATA OF THE AUTHOR 129

xv

LIST OF TABLES

Table Page 1 Area and production of cocoa beans 16

2 Production cost of cocoa crops 17

3 Main and mid-crop according to countries 24

4 Estimation of nutrient requirements of cocoa plants at 28 different stages of development from whole plant analysis

5 Manuring and liming program based on different rainfall 29 pattern, flowering and fruiting seasons in Malaysia

6 The amount of fertilizer 40

7 The physical characteristics of the Segamat soil 51

8 The initial chemical characteristics of the Segamat soil 52

9 The initial nutrient status of the cocoa leaves 53

10 Nutrient status in soil after treatments 55

11 Nutrient status in leaf after treatments 57

12 Effects of treatments on the variables measured (clone KKM 22) 63

13 Effects of treatments on the variables measured (clone PBC 130) 63

14 The fertilizer amount used in the cocoa seedlings experiment 71

15 Effect of treatments on the variables measured (clone KKM 22) 75

16 Effect of treatments on the variables measured (clone PBC 130) 75

17 Nutrient status in soil after treatments 78

18 Nutrient status in leaf after treatments 79

19 Correlation between pH, macro- and micronutrients in soil 81 after treatments (KKM 22)

20 Correlation between pH, macro- and micronutrients in soil 82 after treatments (PBC 130)

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LIST OF FIGURES

Figure Page 1 Leadings cocoa producers 2004/05 crop year forecasts 10

2 Main consuming countries in 2003/04 11

3 A diagram showing a cocoa plant 21

4 Illustration of cocoa cultivation and marketing process 31

5 Cherelle wilt and developing cherelle 34

6 The layout of experimental plots 38

7 The experimental plot 38

8 Successful cherelle (pod) 48

9 Pods production at different months 61

10 Pods production according to treatments 62

11 Dry bean yield according to treatments 62

12 A 3-months old seedling 68

13 Seedling transfered to a bigger polybag 68

14 The layout of pot experiment 69

15 Plastic cover to avoid foliar spillage to other polybag 70

xvii

CHAPTER 1

INTRODUCTION

Commercial cultivation of cocoa in Malaysia commenced in the early fifties when the

United Cocoa Development Company successfully planted some 239 hectares in

Terengganu. Later planting expanded to the East Malaysia, Sabah which became the

leading state to grow monocrop cocoa in Malaysia. The high price of cocoa beans in

world market and support from the government under the crop diversification

program of Second Malaysia Development Plan has influenced the rapid expansion of

the industry.

Although the average yields of many agricultural crops have increased dramatically in

recent years, the average yield of cocoa has shown very little increase and in some

areas, it has actually fallen. One of the problems related to the decrease in cocoa bean

production over the years is low soil productivity which only achieve 0.98 t/ha in

2003 (Malaysian Cocoa Board, 2003). Most cocoa in the country is grown on highly

weathered soils, known as Ultisols and Oxisols. The low soil productivity is due to

acid reaction, low cation exchange capacity to retain nutrients and Al toxicity.

Recently, the area under cocoa has decreased drastically to 50, 824 hectares. The

decrease is attributed principally to poor prices for cocoa beans, poor maintenance

and declining hectarage. Areas which are suitable for cocoa are replanted with other

crops such as oil palm and rubber, while marginal soil is used in new cocoa

development areas (Malaysia Agricultural Directory and Index, 2003).

The quality of the cocoa bean is important due to the natural variability which exists

in cocoa. High residual acid content, very low chocolate flavour and bitter taste is

usually associated with poor quality bean, which contributes to the lower prices of

Malaysian cocoa beans compared to Ghana cocoa beans i.e. the normal commercial

standard (Bakri et al., 1994). The quality of cocoa products can also be determined

by shell content and the fat component of the dry nibs (Lockwood et al., 1994).

There are several physical characteristics which affect the poor quality on cocoa

beans to Malaysian industries. It includes strong acid taste of cocoa beans. All cocoa

beans are acidic to a certain degree, most to an extent that is acceptable for chocolate

manufacture, but when the amount of acids (the acids concerned are acetic and lactic)

in the beans is excessive there will be an adverse effect on the flavour of the finished

chocolate (Pilkington, 1994).

Bean weight is influenced by the type of planting material and by the rainfall during

the development of the pod. As bean size falls, average shell content rises. Shell

content is known to vary within genotype and independently of bean size. Shell

2

percentage should be as low as possible, consistent with adequate protection of the

nib from mould and insects as shell is removed in manufacture and is of very little

value. The content of cocoa butter is usually expressed as a percentage of the dry nib

or cotyledon. The change in fat content is probably affected by climatic factor. The

beans develop during the monsoon gives normal size beans, shell percentage and fat

content.

Another problem is poor yield of cocoa beans. This may be related to cherelles wilt

problem. Young cocoa fruits or cherelles stop growing and turn yellow a week later

and then blacken and shrivel, but remain on the tree. This phenomenon occurs during

the first half of the pod development period and called cherelle wilt. The incidence of

wilt increases from pollination to a peak at about 50 days, then falls off and rises to a

second peak at 70 days. No further wilting takes place after 95 to 100 days. Many

young pods or cherelles die because of the physiological condition of the tree, more

pods being set than the tree’s food reserves can support. Like all other tree crops,

cocoa has its thinning mechanisms. Over 80 percent of cocoa pods may abort

prematurely through cherelle wilt (Hadley and Pearson, 1994). Furthermore, trees

supporting large numbers of pods often tend to produce smaller pods and beans.

Since there is no specific diagnosis on the cause of cherelle wilt, there are many

assumptions have been made including physiological disturbance, pest damage,

diseases and imbalance nutrient supply.

3

Competition between cherelles and new shoot to gain nutrient and water has been

proven. Cherelle wilt will increase during the emergence of new shoots (Nichols,

1964). N, Ca, Mg and Mn are required in high rate at the early stage of cherelle

development. Insufficient in Ca will cause the cherelle loose its tolerant towards

fungus and cherelle wilt will continuously occurred even though the development of

pods has completed (Shear, 1975). In plant nutrition, Ca is an extremely important

mineral but only few soils contain adequate amount of Ca. Many soils of the humid

tropics contain insufficient Ca to maintain a suitable degree of base saturation of the

soil colloids. In such soils, exchangeable Al dominates the exchange sites of the clay,

contributing the excessive soil acidity and soluble Al is toxic to many plants. The

amount of Ca in the soil solution is dependent on the amount of exchangeable Ca

present (Philip, 1998). The soil factors believed to be of the greatest importance in

determining the availability of Ca to plants are the degree of saturation of exchange

complex, the types of soil colloids and the nature of the complementary ions adsorbed

by the clay.

Chemical properties of soil material provide a broad measure of the capacity of a soil

to supply the nutrient requirements of cocoa on a continuing basis. Cocoa is not

tolerant to low soil fertility, but can be established provided that there is a suitable

management practice. Total N, organic P, the cation exchange capacity and the sum

of exchangeable bases (within certain pH limit) are highly positively correlated with

4

the organic matter content of the soil (Room and Ranjit, 1981). A weakly acid soil

with pH 6.0 or above and a major fraction of Ca in the exchangeable bases, as well as

high organic matter content are considered the favourable soil for cocoa.

The role of soil organic matter also lies in ameliorating non-nutritive stress such as Al

toxicity. Organic fertilizers are derived from plants, animals and waste of plantation

such as compost, green fertilizer, POME and waste from animals such as blood, urea

and bones. Organic matter can improve soil structure and fertility (Ofori-frimpong

and Rowell, 1999). With addition of organic matter, a sandy soil will be more fertile

which increase soil water holding capacity and soil structure will be improved. There

are a few functions of soil organic matter which include nutrients storage such as N,

P, S, increase cation exchange capacity, provide energy for soil microorganisms’

activities and stabilize the soil structure (Shamshuddin et al., 2004). High organic

matter will increase soil aggregates stability.

Marginal soils with low fertility are mainly available for cocoa plantation while areas

suitable have been replanted with other crops. Low yield in such soils associated with

low quality of cocoa. Many attempts have been made to solve this problem, as the

cocoa dry bean yield keep decreasing constantly. Poor cocoa beans quality

contributes to the lower price of Malaysian cocoa beans. The current average yield/ha

5

per year is 1.1 tonnes, which is still far behind the target yield of 1.5 tonnes.

Economically, the most important current product of cocoa tree is in the cocoa beans

which can be further processed into cocoa butter and other industrial products. The

perfect management will produce bigger cocoa beans with average of 1 g per dry bean

with thinner cotyledons.

There are a few ways of producing most of the best yield and quality of the crops

which includes additional mineral fertilizers, especially in developing countries, the

use of new varieties allowing for more or better harvests, of new agricultural

techniques and other agrochemicals (herbicides etc.) (Eibner, 1985). Fertilizer

recommendations for cocoa are not possible without adequate knowledge of the soils

of the area and their responsiveness to applied fertilizers. This can only be achieved

through soil testing and field experimentation. It is generally assumed that

agricultural systems with perennial crops are more sustainable than systems with

annual crops. Soil erosion is negligible and perennial crops have more closed nutrient

cycling. Moreover, inorganic fertilizers are used more commonly in perennial crops

so that soil fertility decline and nutrient mining are less likely to occur (Hartemink,

2005). The need for a more intensive and economic agricultural production has led to

a balance of nutrients that would combine the positive characteristics of both organic-

based fertilizers and foliar fertilizers.

6