Sorption Behavior of Butachlor in Agricultural Soils of Golestan Province, Iran.

This study was undertaken to evaluate sorption behavior of herbicide butachlor, to eight arable soils in Golestan province, Iran. Adsorption kinetic and equilibrium studies were carried out using a standard batch equilibrium technique to determine the adsorption coefficients and isotherms of the butachlor under laboratory conditions, which may be extrapolated to natural conditions. Adsorption sharply decreases at the low concentrations and then approaches relative unity in the upper concentration range. The Kd values ranged from 5.05 to 29.07 L/kg. The highest average adsorption percent of the butachlor was measured in soil E with highest organic matter content, while soil G with lowest OM content had lowest average adsorption percent. In all cases, the qe values increased with solution equilibrium concentration Ce in adsorption isotherms.