Essential Elements in Coconut Nutrition
Among the primary nutrients, potash (K) plays the most important role in coconut
cultivation, followed by nitrogen (N). Studies indicate that Phosphorous (P) is relatively less
significant, except in certain restricted areas.
Of the secondary nutrients, the most beneficial is magnesium (Mg) and chlorine (Cl),
followed by calcium (Ca), Sulphur(S) and sodium (Na). Of the micro-nutrients, zinc (Zn),
boron (B) and manganese (Mn) are required under certain restricted conditions.
Potash
Potash helps the development of coconut kernel and the formation of oil in it. An increase in
the level of potash in the leaves improves flowering and increases the number of female
flowers; the number of bunches per palm; the average copra per nut and the total copra
production per palm. Potash helps root development, enabling the plant to take up more
nutrients from the soil. Potash is necessary for the formation of sugar, fat, and fibrous
material. Therefore the coconut palm has a high requirement for potash. K regulates water
economy and thus enables the palm to withstand drought. Potash increases the resistance
to certain pests and diseases. K in combination with Cl reduces the leaf spot disease
incidence.
Nitrogen
Nitrogen is a constituent of plant cells as well as chlorophyll, the green colouring matter of
leaves. It is important for the rapid development and growth of trees. Nitrogen stimulates
the development of the vegetative parts of the plant such as the leaves and shoots and
increases the number of leaves. Nitrogen deficiency is usually reflected in the restricted
growth and yellowing of young and old leaves. Nitrogen deficiency is often more apparent in
young plantations.
Potassium and Nitrogen Interaction
K and N ratio is critical. An imbalance will lead to hindering the absorption of N. K alleviates
the injurious effects of an over-supply of nitrogen. A high level of N is found to adversely
affect the response to K. However, K and N in a particular ratio show a positive effect on the
number of bunches and the number of flowers per bunch. An increase in nitrogen doses in
the absence of P leads to a corresponding increase in the incidence of leaf-spot disease.
Phosphorus
Phosphorus is a component in leaves and seeds and in parts of the plants where vigorous
cell division takes place. It plays a role in root growth and increased yield. Phosphate
enhances the flowering and the ripening of fruits. Phosphate application considerably
increases the production of nuts and copra content. However, an overdose of phosphate
results in the production of barren nuts.
Potassium and Phosphate Interaction
The effect of phosphate becomes evident only when used in combination with potash or
nitrogen. Both potash and phosphate promote flowering, fruit setting, root development
and enhance ripening. Together P and K increase the copra content per nut and the number
of nuts per palm. Further, they increase resistance to certain diseases and pests.
Effect of N, P, K in Combination
The growth and productivity of coconut palms are achieved only when P and K are provided
with N and thus the combined effects of N, P and K are achieved in plant metabolism.
Lime
Calcium is important as a nutrient in acidic laterite soil. Lime regulates base saturation and
pH. Quick lime or freshly slaked lime also increases the coconut yield. However, the actual
lime requirement of coconut is small and this can be met by calcium in the bone meal,
superphosphate, etc. Lime influences the absorption of water-soluble K by plants. The best
utilization of growth factors by coconut palm is obtained at pH 6.0 at an equal concentration
of Ca and potash.
Magnesium (Mg)
Magnesium (Mg) has beneficial effects on the growth and productivity of palm. Magnesium
sulphate increases the production of more female flowers and results in more nuts per
bunch. Mg deficiency is most prevalent in acidic sandy soil. The quantity of Mg in sandy soils
is correlated with the availability of organic matter.
Manganese (Mn)
Manganese has an indirect effect on the formation of chlorophyll and it accelerates the
early growth of seedlings.
Chlorine (Cl)
Chlorine helps to accelerate growth, early flowering, setting of fruits and increase in copra
weight per nut. Chlorine facilitates better absorption of potash, phosphate and magnesium.
Sodium (Na)
Applying common salt in the basin of the coconut is a common practice. Sodium promotes
early growth of seedlings, development of young palms, and augments the number of
inflorescences; production of female flowers and setting of fruits. Adding common salt in
planting pits softens the hard laterite bed and helps early penetration of the tender roots.
Sulphur
Sulphur in the nutrients leads to yield improvement and an increase in the oil content. The
sulphur requirement is usually met through the application of ammonium
sulphate/superphosphate to the crop. Sulphur deficiency leads to yellowing of the leaves,
reduces vegetative growth and hinders the hardening of the kernel.
Boron (B)
Boron deficiency causes mal-formation of the young leaves, showing crown-choking
symptoms, mostly on young-bearing palms. This can be corrected by application of borax at
100 g/palm approx.
Nutrients for Young Plants
Regular manuring right from the first year of planting is essential to ensure good vegetative growth, early flowering and bearing and sustainable yield of coconut palms.
Organic manure at the rate of 30 kg per palm per year may be applied with the onset of the southwest monsoon when the soil moisture content is high. Different forms of organic manures like compost, farmyard manure, bone meal, fish meal, neem cake, groundnut cake, gingelly cake, etc., could be used for this purpose.
The first application of chemical fertilizers should be done after three months of planting. The recommended application of farmyard manure and chemical fertilizers is as follows:
The recommended application of farm yard manure and chemical fertilizers is as follows:
Abbreviations used:
- FYM is abbreviation for Farm Yard Manure.
- Fertilizers are labelled N, P or K to indicate their nutrient content in terms of nitrogen (N), phosphorus (P), and potassium (K). All three are important for plant growth.
Source: Asia Farming, Coconut Farming Information Guide
Rock phosphate is recommended as source of phosphorus in lateritic and acidic soils.
Nutrients for Adult Coconut Palm
The use of fertilizers and manure for coconut cultivation, by and large, depends on the type of soil and its nutrient content.
Regular manuring is essential for the coconut from the first year onwards to achieve higher productivity. The annual requirement will be in the range of 20 – 50 kg of organic manure and it should be applied at the onset of the southwest monsoon when the moisture content in the soil is high. Organic manures such as compost, farmyard manure, bone meal, fish meal, neem cake, groundnut cake, etc., could be used. Ideally, from the 5th year onwards, 50 kg of farmyard manure could be applied.
Chemical fertilizers
For adult palms, the generally recommended application of fertilizers involves 500 g N, 320 g P and 1200 g K per palm per year. To obtain the above quantity of nutrients it is necessary to apply about 1 kg urea, 1.5 kg rock phosphate (in acidic soil) or 2 kg superphosphate (in other soils) and 2 kg of muriate of potash (MOP), as recommended by the Coconut Development Board & ICAR-Central Plantation Crops Research Institute, Kasaragod.
The general fertilizer schedule recommendation for coconut (g/palm) by these organisations is as follows:
Source: Coconut, Coconut Development Board & ICAR-Central Plantation Crops Research Institute, Kasaragod 671 124, Kerala, https://coconutboard.gov.in/docs/coconut-english.pdf
For young plants, the application of chemical fertilizer can be started three months after planting. The quantity of fertilizer to be applied is approximately one-tenth of the recommended dose of fertilizer for adult palms. For the second year, one-third of the dosage recommended for adult palms can be applied in two split doses, in May-June and September-October. During the third year, the dosage may be doubled. Fertilizers may be applied at the rate recommended for adult palms from the fourth year.
There are of course variations in the fertilizer schedule recommended by different sources, partly on account of geographical differences.
A general fertilizer schedule or the palm at different stages of growth of the palm by another source is as follows
Source: Agri Farming, Coconut Farming; Planting, Growing, Care, Harvesting
Guideline for Fertilizer Application
A general guideline for fertilizer application is summarised below:
- Apply fertilizers only when there is adequate moisture content in the soil.
- Under rain-fed conditions, fertilizers can be applied in two split doses, i.e., one-third in April – June and two-thirds in September-October.
- In irrigated areas, fertilizers should be applied in 3 or 4 equal doses during April-May, August-September, December and February-March.
- For an adult Coconut tree 1 kg of dolomite and 0.5 kg of magnesium sulphate should be provided annually.
- Before fertilizer application, make circular basins around the plant with a radius of 2 m and a depth of 10 cm.
- In low-lying areas, fertilizer may be applied in one single dose after the water table recedes, or in two split doses as conditions permit.
For the coconut palm in Kerala at different stages, the fertiliser schedule recommended is as follows:-
Sources: Tamil Nadu Agricultural University, Expert System for Coconut,
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