Indian Institute of Soil Science, Z-6, Zone I, Maharana Pratap Nagar, Bhopal, Madya Pradesh, 462011.
* Present address: Potash Research Institute of India, Sector-19, Dundahera, Gurgaon, Haryana, 122 001.
Reserves and release rates of nonexchangeable potassium were determined in 21 surface soils occurring widely in intensively cultivated areas of India. Nonexchangeable, step and mica-K contents and K release rate showed significant positive relationships amongst themselves. On the basis of potassium reserves, the soils were categorized into five classes, viz. very low, low, medium, high and very high using all the four parameters. The soils in each of the five classes showed similarity in their mineralogy and texture. These soil classes may serve as the basisfor soil test calibration and crop response studies.
Soils of India, potassium reserves, nonexchangeable K, mica-K, step K, K release, categorization of soil K
