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)
|
Coconut palms |
(% on d.m.) |
||||||||
|
Ash |
N |
P |
K |
Mg |
Ca |
Mn |
|||
| Area 1 | } | Broken stalks |
8.17 |
1.85 |
.130 |
1.29 |
.18 |
.10 |
80 |
| } | No broken stalks |
7.51 |
1.78 |
.137 |
1.19 |
.19 |
.11 |
75 |
|
| Area 2 | } | Broken stalks |
7.32 |
2.08 |
.138 |
1.15 |
.25 |
.10 |
90 |
| } | No broken stalks |
7.35 |
2.07 |
.130 |
1.19 |
.26 |
.11 |
98 |
|
| KCa Trial area (Sept. 1972) |
8.08 |
1.82 |
.129 |
1.22 |
.20 |
.06 |
80 |
||
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).
|
Soil pH (air-dry) |
|||
|
0-15 (cm) |
15-45 (cm) |
45-90 (cm) |
|
| Ca0 – nil |
3.87 |
3.50 |
3.31 |
| Ca1 – 5.5 kg limestone/palm/yr. |
4.48 |
4.04 |
3.40 |
| S.E. ( ± ) |
.30 |
.14 |
.07 |
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)
|
|
No. of fronds/palm |
Frond 14-hybrids |
Frond 14-dwarfs |
|||
|
Hybrids |
Dwarfs |
Length (cm) |
Leaf area (m2) |
Length (cm) |
Leaf area (m2) |
|
| Ca0 |
32.4 |
25.4 |
390 |
10.4 |
347 |
8.19 |
| Ca1 |
29.5 |
24.6 |
390 |
10.6 |
356 |
8.26 |
| S.E.( ± ) |
1.0 |
0.8 |
7 |
0.2 |
9 |
0.3 |
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)
|
|
Hybrid palms |
Dwarf palms |
||||
|
Nuts/palm |
Copra |
Copra |
Nuts/palm |
Copra |
Copra |
|
| Ca0 |
440 |
51.8 |
118 |
266 |
28.8 |
108 |
| Ca1 |
440 |
57.3 |
130 |
264 |
30.4 |
115 |
| K0 |
456 |
55.1 |
121 |
263 |
29.4 |
112 |
| K1 |
424 |
54.1 |
128 |
267 |
29.8 |
112 |
| S.E.( ± ) |
15 |
2.3 |
9 |
1.1 |
||
Leaf analysis results are in Table 15 .
|
Leaf 14 (% on d.m.) |
||||||
|
Ash |
N |
P |
K |
Mg |
Ca |
|
| Ca0 |
8.48 |
1.67 |
.123 |
.91 |
.28 |
.12 |
| Ca1 |
7.62 |
1.64 |
.121 |
.82 |
.25 |
.22 |
| K0 |
8.06 |
1.65 |
.121 |
.77 |
.28 |
.16 |
| K1 |
8.04 |
1.65 |
.123 |
.95 |
.26 |
.17 |
| S.E.( ± ) |
0.17 |
.03 |
.001 |
.04 |
.01 |
.01 |
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 (1977) |
1974 – 1977 (3½ years) |
||
|
Pods/tree |
Wet bean kg/tree |
||
| Ca0 |
7.94 |
42.6 |
3.69 |
| Ca1 |
8.79 |
66.7 |
6.28 |
| K0 |
8.15 |
50.6 |
4.60 |
| K1 |
8.57 |
58.6 |
5.36 |
| S.E.( ± ) |
.32 |
8.7 |
.79 |
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
|
Leaf 14 (% on d.m.) in 1976 |
|||||||
|
Ash |
N |
P |
K |
Mg |
Ca |
Mn |
|
| Ca0 |
8.68 |
2.18 |
.144 |
1.65 |
0.69 |
0.36 |
268 |
| Ca1 |
8.63 |
2.27 |
.155 |
1.33 |
0.83 |
0.67 |
202 |
| K0 |
8.48 |
2.21 |
.147 |
1.18 |
0.80 |
0.54 |
243 |
| K1 |
8.83 |
2.23 |
.151 |
1.80 |
0.72 |
0.49 |
227 |
| S.E.( ± ) |
0.51 |
0.07 |
.013 |
0.11 |
0.08 |
.05 |
80 |
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.