Potassium Supplying Power of Soils from the East Khasi Hills of Meghalaya

The potassium release from thirty soil samples of East Khasi Hills of the state of Meghalaya was assessed by exhaustive cropping, successive extraction with 0.01N HCl and with boiling 1N HNO₃. The level of exchangeable K decreased by 13.2 to 80% after five croppings of maize and finger millet. The removal by the first two crops almost accounted for the loss of exchangeable K and the remaining three removed the K from the non-exchangeable form. The per cent uptake of non-exchangeable K decreased with increase in exchangeable K; total K removal by the crops gave negative relationship with the per cent of non-exchangeable K released. Both exchangeable and released non-exchangeable K were significantly correlated with K uptake and dry matter yield. The K fixation power of the soil showed a high degree of correlation with plant K uptake and non-exchangeable K released. The maximum amount of K which could be released by successive extraction (b index) with 0.01 N HCl was highly correlated with exchangeable K and K uptake by the plants.