5. Assessment of Fertility Status of Soils Supporting Coconut (<i>Cocus nucifera</i>) Cultivation in Western and Central Regions of Ghana

Abstract

Coconut cultivation is mostly practiced in the Western and Central regions of Ghana. Information on the fertility status of the soils on which coconuts are grown and possible fertilizer recommendation is not common. Since
coconut yield is generally related to the fertility status of the soil, a study was conducted to evaluate the fertility status of soils supporting coconut in the Western and Central regions. The soils were sampled at three depths, 0–20 cm, 20–40 cm and 40–60 cm at 21 different sites. The soil physical properties do not constitute any major limitation to good coconut growth and yield. Evaluation of the top soil showed that the mean top soil pH was very strongly acidic (4.1 + 0.12) and far below the acceptable limits for good coconut yield. Mean exchangeable acidity [0.57 0.06 cmol(+)kg-1] was relatively high while exchangeable basic cations (Ca, Mg and K) were generally very low. Mean effective cation exchange capacity (ECEC) of 3.1 0.48 cmol (+) kg-1was very low. Mean organic matter status 22.1 1.9 gkg-1 was moderate. Mean available phosphorus of 2.8 0.56 mgkg-1 was very low and one of the major nutrients that will affect coconut yield. Except for soil pH, nutrient levels generally showed a decreasing trend in the order top soil > subsoil > sub-subsoil. The evaluation showed that the soils suffer from multi-nutrient deficiency. Nutrient levels of the soils are low to very low, and will not support good coconut growth and yield. Liming to improve the exchangeable basic cations and pH of the soils is recommended. Use of rock phosphate is also recommended for raising the levels of both phosphorus and some basic cations. Amendments and fertilizers with high K content must also be considered.