Studies on the Nutrient Status of Some Coconut Soils in Ceylon 10. Minor Soil Series and Conditions in the Chilaw District

Summary

The results are reported of pot experiments, using indicator plants, on the nutrient status of three soils varying in fertilizer history. All soils were deficient in nitrogen, and in the absence of added nitrogen yield of grass was below 10 per cent of the potential. All forms of nitrogenous fertilizers were equally effective. All soils showed an acute deficiency of phosphorus at the early stages of the experiments, but with time, and depending on the amount of fertilizer applied in the past, the response to phosphorus decreased. There was little or no response to potassium at the early stages of the experiments, but relative yields later fell linearly with time. Calcium was necessary in small quantities as Ca(OH)₂, CaCO₃ to correct soil acidity, particularly for legume growth. Magnesium increased yields at the latter stages of the experiments. Sulphur was deficient in all soils. The soils had adequate amounts of the minor nutrients. A cheap and quick technique was used with simple and factorial designs to obtain preliminary information, as a guide to planning detailed field experiments on the nutrient requirements of perennial crops like coconuts and other intercrops.