Response of coconut (Cocos nucifera) to N, P and K fertilizer application from the time of field planting on a lateritic gravel soil in Sri Lanka

摘要

The results of a long term 3x3x3 NPK field experiment with coconut from the seedling stage upto initial bearing period on a lateritic gravel soil in Sri Lanka, where the rates of fertilizers were progressively increased upto the 16th year, are discussed. The data from the sulphate of ammonia, 1.136 kg saphos phosphate and 2.043 kg muriate of potash/palm/yr from the 16th year. Application of 1.362 kg each of sulphate of ammonia, saphos phosphate and muriate of potash between the 9th and the 16th years produced an yield of 20.7 kg copra/palm/yr from the 13th to the 16th years, which is about 150perc. higher than the plots which received no fertilizer from the seedling stage. The data suggest that in the current fertilizer recommendations, for both young and adult palms, the rate of N could be reduced and that of K increased.