Different forms of potassium and release pattern of nonexchangeable potassium in some selected acidic soils of West Bengal.

摘要

A study was conducted to assess the different forms of potassium and release pattern of nonexchangeable potassium (NEK) in some acidic soils of West Bengal belonging to soil orders Mollisol and Alfisol. The mineralogical composition of the soils varied widely. The nonexchangeable potassium content of the soils from Falakata, Raghunathpur, Mohitnagar and New Chumpta showed that these soils were expected to release more K under stress condition effectively. Whereas the NEK of the soil from Matimahal revealed that it might not support K under stress condition, without fertilization. The total K content of soils was considerably lower in Alfisol compared to Mollisol. The reserves of Step-K and Constant rate K were computed by repeated extraction of soils with boiling 1M HNO₃. The cumulative release of nonexchangeable K by such repeated extraction followed a semi-logarithmic behavior with number of extractions, suggesting that the release of nonexchangeable K decreased with successive extractions. The results indicated that the Step-K was significantly and positively correlated with NEK.