Cocoa: Planting Systems

In Malaysia numerous systems of planting cocoa have been tried. Growing cocoa under rubber, oil palm and coconuts have all been reported by various authors (Blencowe, 1967; McCulloch, 1967 and Ramadasan et. al. 1978). At conventional planting distances, rubber and oil palm are too competitive particularly for light to produce good cocoa yields.

However, satisfactory yields of both cocoa and oil palm can be achieved by intercropping cocoa with oil palm planted in wide avenues. (Lee & Hanafi, 1978)

The cocoa-coconut intercropping system has also changed. The days of high coconut stand intercropped with cocoa are past. Present emphasis is to plant more cocoa and use coconut as a minimum economic top shade. Some have gone to the extreme of planting monoculture cocoa. (Wills, 1980 and Basket et al., 1982).

Numerous other cocoa-coconut planting systems and patterns are also commonly practiced. The most common ones are MAWA planted regularly at 9m x 12m to 12m x 12m (69 to 92 palms/ha) as permanent top shade intercropped with cocoa at 3m x 3m (1019 to 1042 bushes/ha). Temporary shade such as Gliricidia maculata and Gajanus Cajun are planted together with MAWA about a year ahead of cocoa to provide initial shade. The temporary shade trees are gradually removed completely in stages as the MAWA matures.

More recently, planting of MAWA or oil palm in twin rows in wide avenues intercropped with cocoa has also been tried on experimental scales. The main advantage of this system is that field mechanization can be carried out with ease. Machinery and field workers can move along the wide paths in between the MAWA/oil palm twin rows without undue impediment.

The planting patterns are illustrated in figures 1 and table 3.

The main reason for intercropping cocoa with coconuts or oil palm is that such systems utilize the land more efficiently than the monocrop systems. Since mature cocoa requires some protective shade, it is logical that planting shade trees producing economic crops would improve the viability of a planting. However, they should not be too competitive, particularly for light. In this regard, coconut is superior to oil palm. From an agronomic point of view, an evenly spaced shade (eg. coconut at 12 m x 12 m) is better than shade trees planted in avenues (eg. intercropping systems listed in table 3). However, each system has its advantages and disadvantages and these must be tailored to suit one’s objectives.

Fig : 1 : MAWA/oil palm in twin rows in wide avenues intercropped with cocoa

Cocoa: Nursery Practices

Nursery practices should be geared to produce really well grown and vigorous seedlings free from major pests and diseases. There is really no substitutes for starting off with really well nursed planting materials. Cutting corners in the nursery such as overcrowding the seedlings to save space and planting out small undersized seedlings usually only ends up more costly in the fields. Small seedlings are more difficult to look after in the field. They cannot withstand adverse growing conditions as well as the well grown seedlings and also come into bearing much later. Longer immature period means higher cost and poorer cash flows.

Major nursery operations and the recommended practices are briefly outlined below:-

Ordering cocoa seeds

Seeds must be ordered well in advance from several reputable sources particularly where large plantings are involved.

Essentially, one must ensure that adequate quantities of the desired crosses are available for planting at the correct time.

The number of seeds that must be ordered depend on the planting density, expected losses in the nursery from non-germination, runts, poor growth, pests/disease damage and losses in the field after planting.

For example if	:-	the number of planting points	=	A,
		the number of non-germination	=	x %
		the number of nursery losses	=	y %
		the number of field losses	=	z %
The number of seeds that must be ordered

Under normal circumstances, about 40% extra seeds must be ordered to allow for non germination, nursery culling and supplying.

Nursery site/space/shade

Nursery site should be well drained, close to cheap sources of adequate and reliable water supply and good top soil (potting media) and to the area to be planted; well protected from animals and theft and within easy reach for supervision.

The allotted area should allow for spacing of polybags and also for drainage, paths and transport access. For good growth and to avoid etiolation, the seedlings should be spaced depending on the nursery period (Table 2).

Table 2 : Nursery spacing and polybag size

The ideal shade for nursery is one that can be adjusted to transmit the required amount of light for optimal growth. At sowing, the shade should be about 80%. The shade regime should be gradually reduced to about 50% at field planting, usually at 5-7 months.

Potting media/polybag filling

Only good top soil, preferably from the top 75 mm of soil should be used for filling the bags. The soil medium should allow good drainage and root growth and should not disintegrate when the bag is removed at transplanting. Recommended textures are sandy clay loam to clay loam.

If heavy clay has to be used, coarse river sand in the ratio of 1:4 should be added to improve drainage and aeration. A homogeneous mix may be achieved with the aid of a rotavator/cement mixer.

Basal fertilizers if recommended should be mixed thoroughly with the potting medium. This can be satisfactorily done in convenient heaps with the aid of a changkul/spade. However, it is important that the soil to fertilizer ratio should be correctly calibrated.

pH of soil, if not already known, should be checked and corrected to 5.5 to 6.5 unit.

Bag filling is more efficient if a hopper and funnel is used. Bag bottoms should be folded in so that bags sit better.

The soil should be allowed to settle in the bags before planting of seeds. However, bags should not be filled more than 2 to 3 weeks in advance of planting and should not be filled when the soil is wet.

The bags should be spaced out at the suggested spacings prior to planting. Spacing at a later stage is undesirable as the growth of cocoa seedlings are adversely affected if shifted. At the same time, double handling of large numbers of bags is labour intensive and expensive. Delay in spacing out is also not uncommon, resulting in etiolation of the seedlings. This is extremely undesirable. Etiolated seedlings are difficult to establish and grow poorly in the field. In extreme cases, the seedlings have to be supported to remain erect.

Planting seed

On receipt, the bags holding the seeds should be opened and spread out immediately by a responsible person for airing and checking.

This is important as cocoa seeds though properly processed and cleaned can still generate a fair amount of heat in transit. Excessive heat build up can kill the seeds.

Seeds may be planted as soon as they are received. Alternatively, they can be pregerminated prior to planting. The latter method is preferred if non-germination is expected to be high.

Deep planting should be avoided. As cocoa seed germination is epigeal, the cotyledons are pushed above the ground in the process of germination. Hence one should not attempt to cover up the seeds with soil as the cotyledons emerge from the soil during germination.

Watering

Watering is perhaps the most important single requirement in a polybag nursery. Adequate water should be supplied for good growth. However, over-watering especially in the first 2-3 months should be avoided as the young cocoa seedling is extremely sensitive to water-logging.

Watering once a day with ½ to ¾ litre of water per seedling is generally enough. However, the correct rates may be determined by checking the moisture content of the potting media. It should be moist at the top and bottom of the bag. Increase the rate if the soil is dry and withdraw/decrease the rate if it is too wet. During unusually long spells of dry weather, it may be necessary to water the seedlings twice a day.

An overhead sprinkler irrigation system if feasible is advantageous. Sprinkler output will determine the length of sprinkling. An equivalent of 6 mm rain/day is generally adequate. However, the rates should be checked by examining the moisture content of the potting media. Distribution of the sprinkler system should be regularly checked to ensure even watering.

Pests and Diseases

The most likely nursery pests are the leaf eaters, particularly cockchafers. Cockchafer damage is normally higher along the road sides and in the more open areas where there are less vegetative barriers. As even moderate loss of leaves can set back the growth of seedlings severely, appropriate control measures such as regular insecticide spraying or erecting vegetative barriers of fronds along the perimeter should be carried out.

Common nursery diseases are Phytophthora blight, Collectotrichum leaf disease and Vascular Streak Dieback. All the 3 diseases can cause considerable losses if not controlled in time. Disease monitoring and control is therefore important in the nursery. A combination of cultural practices (reducing inoculum/humidity and improving drainage) and fungicide spraying usually provide adequate control.

Manuring/records

Nutrient requirements by cocoa seedlings in the nursery stage are not high. Small quantities of balanced nutrient applications are generally adequate to ensure good growth. However, it is important to use good potting media mixed with rock phosphate. The pH of media should also be adjusted to 5.5 to 6.5 with calcium limestone if they are too acidic.

Reference 
Ooi L.H. and Chew P.S. 1985. Some important agronomic and agricultural practices in cocoa estates. TDMB Plantation Management Seminar, Kuala Trengganu

Note: The full list of references quoted in this article is available from the above paper.

Cocoa: Planting Materials

The importance of selecting the planting materials most suited one’s environment cannot be over emphasized.

Ideally, planting materials selected should be precocious, capable of sustained high yields, easy to manage, resistant to major pests and diseases and also highly adaptable. For obvious reasons, the crops should also be able to satisfy buyer quality specifications such as bean size, chocolate flavour etc.

Presently, there is insufficient information on environment-material interaction to allow for “environmat recommendation” as for rubber. However, a fair amount of data is available on the susceptibility/resistance of the hybrids to two major diseases in Malaysia i.e. Vascular Steak Dieback and Phytophthora palmivora . The latter is responsible for both black pod disease and canker in the field as well as seedling blight in the nursery.

Various authors reported that Sca6, Sca12, Pa35, Na32, Na33 and Amelonado are resistant to P. palmivora (Holliday, 1954: Spence & Bartley, 1966; Leather, 1966; and Gunawardena 1966).

Ang (1978) reported that progenies derived from Pa7 are more susceptible to VSD while those derived from Sca6 and Sca12 are most tolerant.

Ooi & Chew (1985) reported that Amelonado and crosses with Amelonado parentage are generally more susceptible to VSD.

Through the Malaysian Cocoa Growers Council (MCGC), the major cocoa growers imported 9 Keravat clones from Papua New Guinea in 1982. Most of the clones are resistant to VSD in PNG. Unfortunately, some of them are very susceptible to black pod disease under PNG growing conditions. The clones have been distributed to the interested parties and are now being evaluated in both the Pen. Malaysia and Sabah.

Therefore, in areas where VSD is a major problem, one should avoid planting Amelonado and its related crosses and also progenies derived from Pa7 clone. Materials selected for VSD resistance should be the preferred choice.

In areas where black pod/canker is a serious diseases, crosses with Sca6, Sca12, Pa35, Na32, Na33 and Amelonado should be the preferred choices. However, Sca6 and Sca12 crosses have been discarded by some planters on account of their lighter beans.

Another factor that must be taken into account is that the performance of a particular hybrid could vary considerably between locations. (Ooi & Chew 1985). It is therefore advisable to plant as many proven crosses of diverse parentage as possible (say 5 to 10) in any planting.

Another reason for planting in large number of diverse crosses is that a high percentage of them are self-incompatible. To ensure efficient pollination and high yields, it is necessary to plant them as mixed hybrids or in series of narrow blocks of 3-4 rows per hybrid. Planting of large blocks of a single hybrid should be avoided unless these are self-compatible. As a rule of thumb, the width of a block of a single hybrid should preferably be not more than 15 m.

A self incompatible hybrid/clone if planted in a large continuous block would result in poor pollination and hence poor yield. This is amply illustrated in Table 1 below:-

Table 1 : Effect of planting large blocks of self incompatible hybrids on the yield of cocoa

Source : Tan (1982)
Key : * UIT1 x Na32 in 72 continuous rows
UIT1 x Na33 in 51 continuous rows cocoa planted in
** Mixed hybrids
Cocoa planted in 1977

The yield of Fld. K where the pollination was poor was only about 24% of the mixed hybrids on average.

To save guard oneself and also to ensure quality of planting materials, all seeds should be purchased from reputable sources with a research backing.

Reference 
Ooi L.H. and Chew P.S. 1985. Some important agronomic and agricultural practices in cocoa estates. TDMB Plantation Management Seminar, Kuala Trengganu

Note: The full list of references quoted in this article is available from the above paper.

Cocoa: Economics

The economics of cocoa-coconut intercropping vis-à-vis oil palm, rubber and coconut have been reported by Lim & Chai (1978) and Chai (1982). The authors reported that cocoa-coconut intercropping is the most profitable of the four crops evaluated.

There are very few published data on the economics of mococulture cocoa. FIDA (1977) reported that it is possible to obtain a positive cash flow in the 4^th year after field planting.

In the light of the current pod borer and VSD problems in Sabah, the economics of planting cocoa in Sabah need to be reassessed critically.

Unless the two pest and disease problems are solved soon, it is prudent for companies having land in both Pen. Malaysia and Sabah to plant more cocoa in Pen. Malaysia rather than in Sabah.

Reference 
Ooi L.H. and Chew P.S. 1985. Some important agronomic and agricultural practices in cocoa  estates. TDMB Plantation Management Seminar, Kuala Trengganu

Note: The full list of references quoted in this article is available from the above paper.

Cocoa: Introduction

This paper attempts to discuss some of the important agronomic and agricultural practices such as choice of planting materials, nursery practices, planting systems, shade/light requirements, shade management systems, pruning, weed control and fertilizer requirements in a seedling cocoa estate. Major pest and disease problems are also highlighted. A short note on economics is also presented at the outset.

The area under cocoa cultivation in Malaysia increased nearly four folds between 1978 and 1984 while production increased by about 6 times for the same period. Planted areas increased from about 57,000 hectares in 1978 to about 226,000 hectares in 1984 while dry bean production increased from about 15,000 tonnes to about 92,000 tonnes for the corresponding period. (UPAM 1984 Annual Report)

As a result of the rapid and large scale development in cocoa cultivation, agronomic and agricultural practices in cocoa estates have also undergone some changes. The cocoa industry in Sabah also had to cope with a new pest, Conopomorpha cramerella , the notorious cocoa pod borer since it was first reported in 1980. More recently, Vascular Streak Dieback (VSD) has emerged as a major disease in Sabah causing large scale planting failures and also crop losses.

Reference 
Ooi L.H. and Chew P.S. 1985. Some important agronomic and agricultural practices in cocoa  estates. TDMB Plantation Management Seminar, Kuala Trengganu

Note: The full list of references quoted in this article is available from the above paper.

Rubber: Horticultural Practices

Field experience of controlled pruning in immature rubber.

Enlarge Appendix 1 – Controlled Pruning System A

Enlarge Appendix 1 – Controlled Pruning System B

Enlarge Diagram 1 – Shapes of trees at three levels of branching

Contributor : Chan Weng Hoong

Rubber: Pests and Diseases

Control of White Root Disease in Immature rubber with 3 systemic fungicides.

Contributor : Chan Weng Hoong

Rubber: Manuring

Manuring in rubber: need for re-evaluation based on case study.

Contributor : Chan Weng Hoong

Rubber: Selection of Clones

Rubber: Exploitation

AAR jacket system: A Promising Improved System of extracting latex from rubber trees.