Department of Agricultural Chemistry, Soil Science and Biochemistry, Orissa University of Agriculture and Technology, Bhubaneswar, Orissa, 751 001.
Potassium release characteristics by repeated extractions with boiling IN HNO3 were studied in the soils from eleven different locations in the watershed areas of Phulbani district, Orissa. These soils are medium to high in available K. Potassium-release parameters like total extractable K, total step K and CR-K varied widely in different locations indicating a ~ide variation in the K-supplying capacity of these soils. Total extractable K and total step K were positively correlated with each other. Both the K-release parameters were also positively correlated with nonexchangeable K, lattice K and total K. Significant positive correlations of total extractable K and total step K with nonexchangeable K having high ‘r’ values (r = 0.86** and 0.88**, respectively) indicate that nonexchangeable K may serve as a good index of the Ksupplying capacity of these soils.
Forms of K, total extractable K, step K and CR-K
