Useful Guidelines For Growers

B.S.I.P. Cocoa Research Provide

Although cocoa research in the British Solomon Islands is still in its early stages, and no firm conclusions can be drawn from the work carried out so far, the research programme being followed there is of interest both to Solomon planters and cocoa growers elsewhere.

BSIP cocoa research was first gun, by the Department of Agri ilture, in 1958 when a small experi ental station was opened at Aimela, ar Auki, Malaita. A much larger ition was opened at Dala, Malaita, 1961, and in 1963 a cocoa :ronomist was appointed and a start ade with a formal experimental ogramme.

Early trials dealt with basic re arch into fertilisers, pruning and acing, but more recently this work is been extended to include oblems of culture and varietal [reduction.

Experiments are being carefully sted so that no recommendations 11 be made unless they are onomically feasible.

In a recently published ex ision pamphlet (No. 11/67) from lich the information in this tide is extracted, the BSIP apartment of Agriculture points out at considerable confusion has arisen am the multiplicity of techniques •w being used by cocoa farmers and at it is “unfortunate that many of ;se practices have no real basis proven research under local con ions and have merely aggravated :al difficulties”. In future research, th the agronomic and cocoa provement programmes will be are closely aligned to the farmers’ eds in an endeavour to remove y misunderstandings.

Main plantings

Dala was selected as a research ition because the major cocoa acre es in the Protectorate are planted Malaita.

TOPOGRAPHY. The area of the perimental station is 243.5 acres, is situated on an uplifted coral nestone platform 150-200 feet ove sea level. Most of the station flat or gently undulating and deal of much of the west coast of alaita.

SOILS. The Dala soils are of a e texture varying between a silty ly loam and a clay. They are rived from colluvial coral lime me material and are generally well

structured throughout the profile with no signs of impeded drainage. The topsoil is dark brown in colour and the subsoil is yellow to red. Acidity varies between pH 6.0 at the surface to 5.5 at a depth of 4 feet. The soils are generally low in potash but well supplied with phosphates and other elements. The nitrogen status is reasonable immediately after clearing but is dependent on the annual leaf cycle, CLIMATE. The annual rainfall is over 100 inches and is well distri buted throughout the year. There is no particular dry season.

Experimental programme

Fertilisers. From the work carried out at Yandina and the reports of various analyses it has been shown that many of the soils in the Pro tectorate are deficient in potash. The first experiment at Dala, therefore, was designed to investigate the effect of this and other fertilisers on the growth of young cocoa. Growth measurements and first year yields soon showed that potash was re quired for satisfactory growth though it was not clear how much as only one rate had been applied, viz., \ lb potash per tree.

The next step was to test a wider range of potash applications to find the optimum economic level for in creased yields. A second experiment was therefore started early in 1967 with potash rates of from 0-5 lbs per tree. These are being applied to six year old Trinitario trees which have been previously yield recorded.

Spacing. Planting distances throughout the Solomon Islands have varied between 10 ft x 10 ft and 16 ft x 16 ft. An experiment was there fore laid down along with the first fertiliser experiment to find the optimum spacing for Trinitario over a range of 5 ft x 10 ft to 15 ft x 15 ft.

No recordings were taken for the first three years, but in the fourth year an attempt was made to assess the effects of management practices such as time and frequency of brush ing to see if the closer spacing re-

Practical Planter

duces maintenance costs. Vigour, time taken to come into bearing and the incidence of pests and diseases are also being studied. This work is still continuing but as yet no con clusions can be drawn.

Shade. Most growers will appreci ate that fertilising and spacing of cocoa are affected by the type of shade under which it is grown. To date it has not been possible to lay down precise rules for adjusting shade under thinned natural bush and it is still impossible to draw a true comparison between “natural” and artificial or planted shade.

No formal shade trials have been carried out as yet but at the time of writing, land is being cleared for a trial to test the interactions of shade, fertiliser and spacing with the object of finding the best combination under local conditions.

Shade species

Work is also being done on the collection and observation of planted shade species to supplement Leucaena which has been tried with varied success in the Protectorate. This experiment will compare high and medium shade densities with no shade, three rates of fertilisers and two extremes of spacing, 8 ft x 8 ft and 16 ft x 16 ft.

Planting. Different planting methods have been tried both by departmental staff and by private planters and there has been consider able controversy as to which method is the best. The work however, has not been based on scientific fact and a formal trial has now been laid down to find the cost and effect on growth of the following planting methods: (i) basketed seedlings (ii) bare root seedlings (iii) beans at stake (iv) pre-germinated in trays.

The pre-germinated tray method consists of beans being planted in a seedbox and pre-germinated up to

1 uch bigger yield on pruned plots

e hardening of the first two leaves, len they are transplanted into the Id. In this way they avoid the sect damage common to seedlings rminating in the field and allow r some selection without the 66 r cent, wastage of beans as in the ike method (iii).

Pruning. The problem of how to une cocoa is also being investiga -1 to find a simple and effective stem. The basic difficulty appears be whether or not the tree should restricted to a single storey or owed to form the natural multi ireyed habit. At present two treat mts are being studied for their ects on yield and management, icse are: — i) all chupons removed i) two leading chupons left to form a second storey >th methods include normal branch jning.

The first two years of yields have Dwn that there is an increase in ;ld of 25 per cent, on the pruned )ts. As the experiment progresses wever, this trend mav be reversed.

Planting Material. When research ;t started at Dala the four types seed available were:— i) Trinitario, open pollinated, from the Keravat introductions i) Amelonado, open pollinated, from the North Borneo intro ductions i) Santa Cruz Trinitario, open pollinated, from the Santa Cruz introductions ) Amazon, open pollinated, from the Fiji introductions.

Although some individual yield :ords were available it was clear it a trial had to be established to upare their performance under own conditions. A trial was started 1964, early vigour being corn red by measuring the growth in th. The first indications at 24 >nths were that:— ) Amelonado was more vigorous than unselected Trinitario and Amazon ) Amelonado was not more vigorous than the Trinitario from Santa Cruz I there was no difference between unselected Trinitario and un selected Amazon.

However, later records showed that Amazon type was proving more orous than the other types and en the number of flowering trees re counted at 27 months this type o proved to be more precocious in the others. These results will be omplete until several years of yield

records can be correlated with girth increment and precocity.

Yields of these open pollinated Trinitario types on private farms have not been very high even when planted on reasonable soils with improved methods and optimum maintenance and clearly the most important limiting factor is the cocoa type.

The original Trinitario introduc tions came from high yielding trees growing at Keravat in New Britain.

However, because they were high yielding in New Britain it did not necessarily follow that they would behave in a like manner under Pro tectorate conditions. In fact when they were distributed to farmers yields have proved to be disappoint ingly low.

It is known that Trinitario seed gives a wide range of tree types, from low to high yielding, and that some show greater vigour than others. If, therefore, we select locally the most vigorous and high yielding trees then we have made a step forward in improving the local plant ing material.

Even so, the range of material available in the Protectorate is still somewhat limited and further imports of clonal material of both Trinitario and Upper Amazon types are desir able to ensure that all potential sources are explored.

In addition a carefully planned selection and breeding programme is essential to produce higher yielding planting material than that currently available. The way this will be achieved is described below.

Cocoa improvement

programme

Improvements can be effected in the type of cocoa being grown in the Solomons by:— (i) selection of local material (ii) importing hybrid seed and its parental material (iii) producing hybrids from local and imported material.

The first can be considered as a short term programme while the others are long term projects. (i) Selection of Local Material.

Records have been kept since 1958 of the individual tree yields on the Trinitario introductions planted at

Aimela Cocoa Observation Station. A study of these records and those at Dala Station has resulted in the selection of 43 high-yielding trees as potential parents for future breed ing work. Seed from most of these trees has been planted at Dala with the following objects in view:— (a) to assess the parents more com prehensively (b) to test suitability for seed distri bution directly from these parents.

Although this method is not strictly conventional, assuming that some of the selections show the desired characteristics, it will in fact mean that improved material will be available in a much shorter time than would otherwise have been possible.

The method also has the advantage that the selections have been made under local conditions. (ii) Importing Hybrid Seed and its Parental Material. BUDWOOD— Plots of Amelonado were planted in 1966 to receive budwood of imported types during 1967. Clonal material of known Trinitario and Upper Amazon types will be established on the Amelonado and grown for observation. This material can eventually be used as a clone itself or in breeding work by hybridising with each other and with local selec tions under part (iii) of the improve ment programme.

Unfortunately the hurricane dam age to the Amelonado plots has set the whole programme back by 9-12 months.

HYBRID SEED A second way of importing hybrid material which will shorten the length of time re quired to provide better planting material for farmers, is the use of hybrid seed. This method involves the importation of hybrid seed of known parentage and at the same time budwood of both the parents.

The hybrid seed will be planted under local conditions and the parents of those which prove to be the best will be used to establish hybrid seed gardens throughout the districts from which hybrid seed will be available for distribution to farmers.

This, however, is part of a long term project and it is not possible to say as yet when work will start, (iii) Producing Hybrids from Local and Imported Material As already mentioned this part of the programme will follow on from part (ii) —Budwood.

It must be emphasised that there is no quick answer to the problem of cocoa improvement and these methods will take anything up to seven years to develop. Ideally, of course, agronomic research should be

layed and applied to the selections d introductions found suitable for :al conditions from the cocoa provement programme but this mid ignore current problems which »ently need solution.

The two lines of research must refore proceed simultaneously in ; hope that results obtained from ds on planting, spacing, pruning, ide and fertilisers will also find application with improved cocoa >es.

Future investigations

Maintenance Problems. One of most important problems facing :oa farmers is the lack of income m the land during the early years establishment. Cocoa cultivation ;s not lend itself to interplanting h foodcrops and once the farm ; been planted with cocoa the ner is reluctant to undertake main ance work from which he sees no nediate return. fhis frequently results in years neglect at a critical period in life of the tree and retards growth severely that the farm may never duce an economic crop. r o provide the farmer with some mtive for maintenance during this icult period, research will be ried out on the use of cash crops h as banana and papaw as iporary shade. At the same time is hoped to find a leguminous er crop which will reduce the aunt of brushing and also improve soil, 4niching. A further method of rcoming maintenance problems is use of mulch as a weed control, is intended to carry out a series trials on different planting systems h as cocoa planted in a hedgerow i mulch plants growing between rows which would provide a alar supply of mulch right where > needed.

'ertilisers. Apart from investigat the type and quantity of fertiliser be applied, work will also be ied out on the time and method application. For example how n it should be applied during the r and whether it should be broad on the ground or placed in ches. In addition the possible d for trace elements will not be rlooked and simple experiments be conducted to find what is dent and how it affects the rient status of the soil and the it.