G.B. Pant University of Agricutlure and Technolgy, Pantnagar, Uttaranchal, 263145.
1Present address: The Fertiliser Association of India, 10 Shaheed Jit Singh Marg, New Delhi-110067.
A new method for S-extraction was tried using strong basic anion exchange resin (Amberlite IRA-400) on seventeen Mollisol soil samples. A four-hour shaking, keeping 1:1 soil:resin ratio was found optimum. Of all the methods compared the resin method had the highest S-extractability from soil. The values ranged from 4.4 to 30.3 mg kg−1 for Morgan's reagent, 4.4 to 28.1 for NH4OAc-HOAc, 1.9 to 21.3 for 0.15% CaCl2, 3.1 to 28.1 for Olsen's reagent, and 3.1 to 22.5 mg kg−1 for MCP (500 mg P L−1), with mean values of 13.7, 12.3, 10.6, 13.6 and 10.3 mg S kg−1, respectively. Two procedures based on anion exchange resin method yielded much higher values, ranging from 48.8 to 65.5 and 50.5 to 70.4 mg S kg−1 without and with H2O2 treatment, with mean values of 57.5 and 59.1 mg S kg−1, respectively. Resin extractable-S was highly correlated with the S content extracted by all other extractants under study.
SO4-S, S-extractant, anion exchange resin, Mollisol
