Coconut: Trial

KCa FERTILISER TRIAL ON COCONUTS INTERCROPPED WITH COCOA IN SEDU SERIES

In 1972, it was noted that `premature’ nut fall incidence was as high as 12 per cent of the nut yield in a Sedu series area. The problem appeared directly due to snapping of the bunch stalk and leaf analysis. Results of groups of palms with and without broken bunch stalks were checked (Table 11).

TABLE 11. LEAF 14 NALAYSIS RESULTS OF COCONUT PALMS WITH AND WITHOUT BROKEN BUNCH STALKS IN ACID SULPHATE AREAS (JULY 1972)

As no clear pattern emerged from the results, it was decided to check the effects of liming and potassium application in the area.

A 2 2 KCa factorial trial was laid down in 1973 on the most affected `premature’ nut fall area with the following results on soil pH, growth, and yields of the underplanted cocoa (1971 planting) and coconuts (1955 planting at 270 palms/ha). The limestone and Muriate of potash were broadcast over a 2 m radius circle around the coconut palms.

Soil pH in the applied area was raised markedly up to 45 cm depth (Table 12).

Liming treatment appeared to depress the number of fronds per palm but had little effect on the frond sizes (Table 13).

TABLE 13. CANOPY MEASUREMENTS OF COCONUT PALMS (1977)

Liming the coconut palms improved copra yields by 10.6 per cent in the hybrid palms and 5.6 per cent in the dwarf palms, primarily by improving copra content per nut. Application of potash at 2.5 kg muriate of potash per palm per year appeared to depress nut yield but increased copra content per unit with subsequent small effect on yields. After 1972 `premature’ nut fall incidence declined markedly to less than three nuts per palm for all treatments (Table 14).

TABLE 14. YIELD OF COCONUTS IN KCa MANURING TRIAL (1973-1977)

Leaf analysis results are in Table 15 .

Liming depressed leaf K and Mg but markedly increased Ca content in the coconut leaves.

Liming had very pronounced effect on growth and yield of the cocoa (Table 16).

TABLE 16. UNDERPLANTED COCOA RESULTS IN KCa TRIAL ON COCONUTS ON SEDU SERIES SOIL

Girth was improved by 10.7 per cent and yield by 70.6 per cent by application of limestone to the coconuts.

Leaf analysis results in the cocoa in 1976 are shown in Table 17.

TABLE 17. LEAF ANALYSIS RESULTS OF UNDERPLANTED COCOA IN KCa TRIAL ON OCONUTS ON SEDU SERIES

Limestone application markedly depressed leaf K levels and increased Ca and Mg levels.

Reference 
Chew P.S., Kee K.K. and Ooi L.H. 1984. Management of coconuts and cocoa on acid sulphate soils. The Planter. Incorporated Society of Planters, Kuala Lumpur 60 (704) : 483-498.

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

Coconut: Planting

COMMERCIAL COCONUTS AND COCOA PLANTINGS ON ACID SULPHATE SOILS

Young Coconuts

There are no young MAWA coconut areas in our group on acid sulphate soils. However, 133 ha of MAWA hybrids were replanted in Estate 1 following rubber in 1980 and 1981 on Briah/Java/Sedu series soils. At the commencement of field preparation, the detailed soil maps were not yet available and following soil pH tests which showed values below pH 3.6 and 4.1 in the top 15 cm, the areas were treated as potentially acid sulphate and field preparations made accordingly. A brief description of the planting practices adopted is given:-

•  Land preparation and drainage. The old rubber was poisoned, felled and burnt. These precautions were taken to minimise rhinoceros beetle problems.

The cleared land was ploughed and harrowed for weed control, to fit new uniform drainage schemes and to level the areas. The practice is useful for mechanization in future and also to benefit the legume growth by reducing initial weed competition.

New drains were then dug at the specifications decided, usually 1 m (width) x 1 m (depth) x 0.5 m (bottom width) at every fourth palm row.

The management was encouraged to practise water management by keeping the water table at 75 cm depth where possible by using weirs in the drains.

•  Planting practices. Standard polybag nursery practices i.e. using 45 cm x 50 cm size polybags, fertilizer schedule (Appendix 2) and daily watering were adopted with satisfactory growth. Top soil was used to fill the bags.

APPENDIX 2. FERTILISER SCHEDULE FOR MAWA COCONUTS IN POLYBAG NURSERY

Leguminous covers were planted in these areas. Again, standard techniques were used although in the acid sulphate areas, liming at 2.5 to 5.0 tons per ha was suggested with apparently beneficial effects to the legumes. Difficulty in establishing and maintaining the legumes in these areas was experienced due to abnormal flooding and probably high acidity. Results obtained usually were legume/grass mixtures.

Normal ring weeding of the palms was carried out to minimise weed competition with the palms.

•  Fertiliser application. The fertilizer schedules followed in the acid sulphate areas are given in Appendix 3.

APPENDIX 3. SUGGESTED FERTILISER SCHEDULES (KG/PALM) FOR HIGH YIELDING HYBRID COCONUTS ON ACID SULPHATE SOILS (CHEW, 1982)

The high rates are to ensure good early establishment and precocious yields for which the MAWAs are famous.

The early growth of the planted MAWAs appeared satisfactory. Only problems were damage by rhinoceros beetles.

Old Coconuts

The policy in all coconut areas is to intercrop with cocoa to maximize profits. Most of the coconut areas on the acid sulphate soils are (>25 yrs) and were planted with a mixture of dwarfs, natural hybrids in 1954/55, at close density for dwarf palms (approx. 6.7 m). Planting practices in these areas are discussed and compared with similar coconut palms planted on non-acid sulphate soils (Sabrang and Briah series) in Estate 2 probably from the same seed palms as Estate 1 and dwarf palms on comparable age in another non-acid sulphate soil (Bernam/Selangor series) in Estate 3.

•  Planting practices. All areas are inter-cropped with cocoa. As this was carried out over a period of years from 1968 and with some considerable conflicting views, planting density and spacings of the cocoa varied considerably but were usually very dense at 750 to 1100 bushes per ha initially and recently thinned down to 530 to 750 bushes per ha.

The ground cover is usually bare of vegetation in view of the dense shade of the cocoa and coconuts and also the deliberate policy of the management to keep out all ground vegetation.

Coconut husks, after removing the nut, which used to be burnt in pre-cocoa planting days are now usually left scattered in heaps in the interrows.

•  Water management. This is stressed in the acid sulphate areas in view of the need for adequate drainage with cocoa planted in the areas and also the potential dangers of higher acidity developing in the soil on over-drainage. Water tables in the acid sulphate areas fluctuated from 0.3 m to 1.2 m but were mostly 0.6 m to 0.9 m.

Often however, with the seasonal rainfall of the estates, excessive water or absence of it was the problem and largely outwith the control of the management.

•  Nutrition. The coconuts were fertilized sparingly as seen in Table 3.

TABLE 3. NUTRIENTS (KG/PALM) APPLIED TO COMMERCIAL COCONUT AREAS (1974 TO 1982)

Fertiliser rates are drawn up on available general information of the nutrient requirements of the palms, leaf and soil analysis results and the fertilizer application made to the cocoa, nutrient requirements of the latter and expected profitability of fertilizer applications made.

Only magnesium applications as magnesium limestone and calcium limestone application were applied at high rates in the acid sulphate areas.

The other feature in the fertilizers applied is the higher nitrogen and potassium application on the Bernam/Selangor series areas. This is in view of the expected responses to nitrogen and the lower leaf K levels.

Applications were withdrawn in the last two years on very low copra prices.

Leaf and soil analysis data on the acid sulphate areas are given in Table 4 and 5 and compared to non-acid sulphate areas.

The soil analysis results given for individual fields in the coconut areas discussed are for fertilized areas in the cocoa interrow areas and mainly unfertilized areas (except for limestone) between the coconut palms.

Soil pH results (air-dry soil) of topsoil samples after 1980 are above four units in all cases. Earlier analysis showed lower pH in the acid sulphate areas but these were subsequently corrected by liming.

Organic carbon, nitrogen and phosphorus contents are higher on the Sedu series than on Bernam series but have lower base cations. Limited analysis results are available for the Sabrang and Briah series areas. Their soil nutrient contents for available P and the exchangeable cations appear similar to the Bernam series.

Nutrients applied to the cocoa are shown in Table 6.

TABLE 6. NUTRIENTS (KG/BUSH) APPLIED TO COCOA AREAS (1976-1982)

High limestone applications were again made in the acid sulphate areas. Applications of nitrogen and phosphorus were lower than on the other soils with approximately similar potassium values.

Leaf analysis results of the cocoa are given in Table 7.

TABLE 7. LEAF ANALYSIS RESULTS OF SOME COMMERCIAL COCOA AREAS ON COASTAL CLAY SOILS

The feature of the results may be higher N and Ca values in the acid sulphate areas.

•  Yields of the coconuts. The coconut yield results in the areas discussed are shown in Table 8 with individual year yield trends in Figure 1.

TABLE 8. COMPARISON OF COCONUT YIELDS (1970-1982) ON ACID SULPHATE AND OTHER COASTAL CLAY SOIL AREAS

In the Malayan dwarf/hybrid areas, there is a gradation of yield increase from the acid sulphate areas to the non-acid sulphate Sabrang and Briah series areas. Yield over the period considered (approximately year 16 to 28) was 38 per cent higher in the non-acid sulphate area. This would be larger probably but for the thinning carried out in 1978 which reduced differences considerably.

The mean yields in the Malayan Dwarf area on the Bernam/Selangor series area appeared comparable to the acid sulphate areas only. However, this may be misleading as unusually poor results (possibly related to abnormally very high rainfall on the estate) were obtained in the last four years despite no thinning carried out.

Copra content figures do not appear to show differences between the different soil areas. However, again this may be misleading due to differences between the years and possibly estate recording methods (Table 9). Copra content is probably better in non-acid sulphate areas.

•  Yields of the cocoa. The cocoa were under planted in the coconut areas in several blocks in each coconut field in the acid sulphate areas due to uncertainty of policy and success over 1968-1975. In the other estates, underplanting of cocoa was carried out in 1968 (Bernam/Selangor area) and in 1969/71 in the Sabrang and Briah soil areas. Planting materials were mainly F1 hybrids.

Yields for some of the oldest plantings have been extracted and yield trends with age for these plantings on the different soils are indicated inFigure 2.

In view of the different planting practices and times, yields up to year five are probably not useful for strict comparison although they indicate that early yield results are also related to acidity of the areas. Yields after year five are shown in Table 10.

TABLE 10. YIELDS FROM COMMERCIAL MATURE COCOA (YR. 6 TO YR. 12) UNDER DWARF/HYBRID COCONUTS ON COASTAL CLAY SOILS

The highest yields were obtained on the Sabrang and Briah series areas under Dwarf/hybrid coconuts. This area outyielded the acid sulphate areas by 59 per cent and 100 per cent. The less acid sulphate areas outyielded the acid sulphate area by 26 per cent. The cocoa in the Bernam/Selangor series outyielded the acid sulphate areas by 44 per cent and 82 per cent.

Absolute yield levels were very low under the generally heavy shade conditions in the acid sulphate areas and even in the non-acid sulphate areas. Improved yield responses seen in Figure 2 in the Sabrang and Briah series area is in part due to reduced shade levels from palm thinning carried out in 1978.

Reference 
Chew P.S., Kee K.K. and Ooi L.H. 1984. Management of coconuts and cocoa on acid sulphate soils. The Planter. Incorporated Society of Planters, Kuala Lumpur 60 (704) : 483-498.

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

Coconut: Acid Sulphate Soils

The acid sulphate soils which are in the coconut areas in our Group of estates were mapped according to the soil identification key drawn up by Paramanathan (1981) and subsequently modified as per Table 1.

Out of 2174 ha of coconuts (mostly underplanted with cocoa), only 338 ha (15 per cent) are on acid sulphate soils of the Sedu and Java Series.

The coconut areas on acid sulphate soils are located in the Bagan Serai (Estate 1) district, and as discussed later, the problem is compounded by difficulties in water management and the markedly seasonal rainfall pattern.

A comparison of the coconuts and cocoa grown on acid sulphate soils in this estate and comparable areas on two other estates on Sabrang and Briah series (Estate 2 in Kuala Kurau district) and on Bernam/Selangor series (Estate 3 in Sabak Bernam district) is given in this paper.

Rainfall patterns for the estates are shown in Appendix 1.

APPENDIX 1. RAINFALL PATTERNS (1971 – 1982) IN COCONUT ESTATES

Reference 
Chew P.S., Kee K.K. and Ooi L.H. 1984. Management of coconuts and cocoa on acid sulphate soils. The Planter. Incorporated Society of Planters, Kuala Lumpur 60 (704) : 483-498.

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

Coconut: Introduction

The yield performances of underplanted cocoa and mixture of dwarf and hybrid coconuts in fields on acid sulphate and non-acid sulphate areas in three coastal estates were compared. The cocoa yields under the heavy shade of coconuts were about 365 to 465 kg per ha per year in the acid sulphate areas against 732 kg per ha per year in comparable non-acid sulphate areas. Coconut yields were 1762 to 2095 kg copra per ha per year against 2439 kg copra per ha per year respectively. Liming from pH 3.9 to pH 4.5 in the topsoil increased copra content per nut and copra yields by 10 per cent and nearly doubled cocoa yields.

Management practices including fertilizer applications, leaf and soil analytical data and water management practices are also described and discussed.

In Peninsular Malaysia, the main areas of established coconut and intercropped cocoa plantations are on the coastal clay soils in the Bagan Datoh, Sabak Bernam/Kuala Selangor and Krian districts. Extensive areas of acid sulphate soils occur amongst the coconut areas. Frequently the presence of acid sulphate soils was not realized until very much later after the coconuts had been planted and when difficulty was experienced in obtaining good results from the under-planted cocoa.

Traditionally, little upkeep and maintenance was carried out in the old coconut areas. Poor performance and yields from the coconuts were often put down to old age of the coconuts and low yield potential of the planting materials. Expectations were therefore low. Information on effects of cultivation practices and management was minimal. With the revived interest in coconuts following cocoa intercropping in the 1960s and the introduction of high yielding MAWA hybrids in the 1970s, more information on coconut cultivation and management has been gathered. However, the research work carried out has been adhoc largely in view of the limited areas of coconuts and cocoa available to support the research programme and other priorities. The problems of cultivating coconuts and cocoa planted in acid sulphate soil areas have not been researched intensively until recently (Zahari et al . 1982). Information on the subject is still lacking. This paper where data from some commercial coconut and cocoa areas on a range of acid sulphate and coastal clay soils are presented may therefore serve as a stop gap measure as further research on the subject is pursued and new information becomes available.

In the group of coconut estates which we were concerned with, updated detailed soil mapping had recently been completed and in this paper, we shall present and discuss our experiences, practices, yield performance and other aspects of management of the coconuts and cocoa which were noted in the acid sulphate areas. A manuring trial was also sited on these soils and the results obtained are also discussed to formulate recommendations for improved performance of the two crops.

Reference 
Chew P.S., Kee K.K. and Ooi L.H. 1984. Management of coconuts and cocoa on acid sulphate soils. The Planter. Incorporated Society of Planters, Kuala Lumpur 60 (704) : 483-498.

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