Distribution of different forms of potassium in some coastal soils of West Bengal

The research work with a view to evaluate the status, availability, fixation, releasing and supplying behaviour of potassium for a meaningful K-fertilizer management strategy for sustainable crop production in the coastal soils of West Bengal. Forty surface (0–15 cm) soil samples representing the coastal soils of West Bengal were used for assessing the important physical and physicochemical properties and distribution of different forms of potassium. Total K and lattice K content of the soils were high ranging between 1.0 to 2.74 and 0.93 to 2.60%, respectively. Non-exchangeable, available, exchangeable and water soluble K contents of the soils varied from 534 to 1050, 68.81 to 284.77, 58.65 to 232.50 and 10.16 to 52.27 mg/kg contributing 3.84 to 6.32, 0.53 to 1.23, 0.45 to 1.02 and 0.08 to 0.22% towards total K, respectively. The overall soils were high in available, non-exchangeable and mineral K status. Based on the district wise average values of the different forms of K, the soils were in the order: Medinipur East > North 24 Parganas> South 24 Parganas. Different forms of soil K had highly significant positive correlation with pH and EC. Non-exchangeable K was significantly and positively correlated with organic carbon and CEC. Available K, exchangeable K and water soluble K had significant negative correlation with sand. All the forms of soil potassium were interrelated, indicating the existence of a dynamic equilibrium among them.