Department of Agricultural Chemistry, R.B.S. College, Bichpuri, Agra, Uttar Pradesh
*Present address: Deptt. of Soil Science, College of Agriculture, G.B. Pant University of Agric. and Techn. Pantnagar, Nainital, (U.P.)
**Present address: Himachal Pradesh Krishi Vishwa Vidyalaya, Palampur, (H.P.)
