Résumé
Adsorption of atrazine was studied on two Vertisols and two Alfisols varying in their physicochemical properties. Soils were equilibrated with various concentrations of atrazine using batch techniques. Adsorption affinity for atrazine was approximated by Freundlich constant (Kf), which is a measure of the strength or degree of adsorption. Kd values were calculated for atrazine despite some non-linearity in adsorption on both Vertisols and Alfisols. The Kd values are greater for Vertisols than Alfisols and increased with organic carbon content. Correlations were worked out between extent of adsorption and soil properties and were positively correlated with organic carbon (r = 0.688), clay content ( r = 0.712) and clay + organic carbon (r = 0.708). KOC values were calculated taking into account the organic carbon content for both Vertisols and Alfisols.