Potassium Supplying Power of Some Soil Series of West Bengal

Minimal exchangeable K level and K supplying power of 18 soil series under three most dominant soil orders of West Bengal were studied by intensive cropping with maize and groundnut as test crops in green house. Minimal exchangeable K level is an unique character of a soil and is independent of the plant species grown. Minimal exchangeable K was significantly and positively correlated with clay content (r = 0.94). Initial level of exchangeable K. released K from both exchangeable and non-exchangeable sources were significantly correlated with the cumulative K uptake and dry matter yield. A significant positive correlation was observed between total release of K from non-exchangeable sources and clay content (r = 0.93 and 0.84 for maize and groundnut, respectively). The K supplying power of almost all the soil series under study were quite poor which otherwise indicated that K nutrition and successful cropping in these soil series would depend largely on the external application of this nutrient element. The sequence of mean K supplying power of three soil orders under consideration was found to be similar to that of mean initial level of exchangeable K. clay content, cumulative dry matter yield and cumulative K uptake i.e. Inceptisol > Entisol > Alfisol.