Adsorption of Herbicide Butachlor in Cultivated Soils of Golestan Province, Iran

Butachlor is a non-ionic herbicide that has been applied widely for agriculture, especially in paddy fields. Through batch equilibration experiments, the adsorption characteristics of butachlor were investigated in eight cultivated soil samples collected from Golestan Province, Iran. The data obtained from adsorption equilibrium experiments fitted the linear equation very well. Results showed that butachlor had weak to moderate adsorption capability in different soils. Trend of butachlor adsorption was similar to the order of abundance of organic carbon in the soils. The Gibbs free energy values were found negative and adsorption was spontaneous and exothermic in nature. Statistical analysis showed that organic carbon, CEC (cation exchange capacity), and the Rt ratio (ratio of TNV to organic matter content) were the more effective parameters governing butachlor retention and mobility in soils.