Activity of the herbicide acetochlor in soil under no-till and conventional tillage systems

Abstract

The activity of herbicide acetochlor in a Red Argisol (Paleudult) under no-till and conventional tillage systems was investigated in laboratory and field experiments. The herbicide was less efficient on weed control under no-till system than under conventional tillage. The reduction of wheat dry matter, evaluated in the sample collected from the 16-19 cm depth, was higher under no-till, suggesting a greater leaching capacity in this soil tillage system. The acetochlor sorption was higher on no-till system than in the conventional tillage, as indicated by the distribution coefficients on soil (K_d): 2.75 and 1.67 L kg^-1, respectively. The distribution coefficients relative to the soil organic carbon (K_oc) were 166 L kg^-1 on no-till and 126 L kg^-1 on conventional tillage, showing that the herbicide was sorbed in a greater extent by the organic matter from the no-till system.