Potassium Releasing Power of Soil as a Tool to Assess Its Supplying Power

The present study was carried out in greenhouse and laboratory to determine how best the K supplying power of a soil can be assessed from K releasing power. Significant positive correlations were observed between cumulative K release and the initial level of exchangeable as well as nonexchangeable K, thus justifying that K status governed the K release characteristics of the soils. Highly significant correlations were also observed between cumulative K release after 5, 10 and 15 times stepwise extraction by 0.01 N HCl and cumulative K uptake as well as dry mailer production. The highest correlation coefficient was observed between cumulative K release in the 5th step of extraction with both cumulative K uptake (r = 0.95 for maize; r = 0.93 for groundnut) and the dry matter yield (r = 0.92 for both the crops). Thus, K supplying power of soil could be predicted from the cumulative K release up to the 5th extraction (0.01 N HCl).