Adsorption of pendimethalin on six different soil samples was studied using batch, shake technique. In general, the adsorption isotherm fitted well in Freundlich equation (r2 > 0.98) and Freundlich's constant ‘K’ and ‘lin’ values were in the range of 10.98–24.41 and 0.706–0.854, respectively. The amount adsorbed was related to clay and organic carbon content (R2 = 0.89). In different soils adsorption was in the order: Mollisol > Vertisol > Inseptisol > Alfisol-1 > Alfisol-2 > Aridisol. Removal of organic matter by H2O4 oxidation caused drastic reduction in adsorption of pendimethalin. Maximum reduction occurred in Mollisol (organic carbon, 1.08%). Sorption property of soil system was not reversible and only about 29.6 to 40.1 per cent of pendimethalin could be desorbed.
Pendimethalin, adsorption, desorption, organic maller, soil
