Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi, 110012.
* Present address: Indian Institute of Soil Science, Z-6, Zone-I, Maharana Pratap Nagar, Bhopal, M.P., 460011.
Potassium fixation characteristics and fertilizer K requirements of illite dominant soils were studied before and after depletion of soil K under exhaustive cropping for 245 days. On K depletion, the exchangeable K levels with added K were reduced drastically. Soils high in initial K showed maximum reduction in exchangeable K as compared with soils low in K. Potassium fixation was higher in K depleted soils. Effect of K depletion on K fixation was more prominent in K rich soils. Unit fertilizer K requirement to increase unit available K was doubled on K depletion.
K fixation, fertilizer unit requirement, K depletion, illite dominant soils
