University College of Agriculture, Calcutta University, 35, Ballygunge Circular Road, Calcutta, West Bengal
*Present address: C/o Divisional Forest Officer, Silviculture Division (South), P.O. & Dist. Midnapore, West Bengal
Humic acids extracted from water-stable aggregates of different sizes (0.20, 0.25, 0.50, 1.00 and 2.00 mm) were fractionated to different molecular weight ranges by Sephadex gel filtration. It was observed that smaller sized aggregates contained higher proportion of high molecular weight humic acid molecules (> 50,000) while larger aggregates contained more of small molecules (< 4,000). Total acidity of humic acid extracted from the bigger aggregates was much higher than that of the smaller one.
Water-stable aggregates, humic acid, molecular size
