Crop Response to Potassium in Sodic Soils in Relation to Potassium Release Behaviour in Salt Solutions

Field studies in semi-reclaimed sodic soil and pot studies in sodic soil with different crops indicated no response to K. This could be related to enormous release of K from K-bearing minerals under sodic soil conditions. The trend of K-release behaviour of illite dominated clay fractions of soils in different neutral solutions of NaCl (0.1 M), CaCl₂ (0.1 M) and CH₃COONH₄ (1 M) indicated a probable mechanism of K-release through a diffusion-controlled process whereas sand fraction contributed a considerable amount of K probably through a process of dissolution. High rate of K-release were found to be related to the increase in seasonal temperature and this might be correlated with the high water soluble K after rice crop in kharif as compared to that after rabi crop.