Dynamics of Different Fractions of soil Potassium in an Inceptisol under Subtropical Rice-Rice System

Field studies were carried out in 2014-15 rabi season and 2015 kharif season at central farm of OUAT, Odisha, India to evaluate different fractions of potassium at different soil depth at different stages of rice crop. The experiment was laid out in randomized block design with 12 treatments and 4 replications. The study revealed that water soluble K, exchangeable K and non exchangeable K content was highest in 100%NPK+FYM+Lime.Watersoluble K decreased from tillering to harvesting for all the treatments in both the seasons. Exchangeable K decreased in rabi season but increased in kharif season through the stages of growth. Non exchangeable K increased from tillering to harvesting in both seasons. Lime application has increased three forms of potassium over 100%NPK treatment. There was decrease in potassium content with depth. Potassium content in kharif season is less than rabi. The correlation between grain yield is highest with non exchangeable K in rabi and exchangeable K in kharif. The K uptake is best correlated with non exchangeable K in rabi and water soluble K in kharif season.