Forms, availability and transformation of potassium in laterite soils as influenced by crop uptake

Abstract

An investigation was taken up to study the fate of applied and native potassium in a laterite soil as influenced by other major nutrients and organic matter and uptake by an annual crop, banana. The experiment was laid out at Banana Research Station, Kannara, Kerala Agricultural University during the period 1996- 1997. The result of the study revealed the necessity of fertilization of the field/soil for better yield. The maximum content and uptake of nutrients N, P and K occurred during the early and late vegetative stages of banana. Hence fertilizers should be applied for the crop from 2 months after planting onwards and continued up to six months after planting. Correlation studies revealed the significant relationship of total K in the soil with yield at different stages. Also poistive

correlation between the exchangeable K content in the soil and yield was established. Path coefficient analysis revealed that the direct effect of total K content in the soil on yield was highest at P4 (6 MAP). The indirect effect was maximum at P4 (6 MAP) through P3 (4 MAP). The exchangeable K also was found to have positive direct effect on yield. The indirect effects were not significant. Water soluble K at different stages showed a direct effect of comparable magnitude on yield.