Effect of soil wetting and drying cycles on metolachlor fate in soil applied as a commercial or controlled-release formulation.

A controlled-release formulation (CRF) has been developed for metolachlor, which reduced its leaching in a sandy soil and improved weed control in comparison with the commercial formulation. The current study tested the effect of soil wetting and drying cycles (WDCs) on metolachlor fate (desorption, leaching, and weed control) applied as the CRF and as the commercial formulation. Metolachlor adsorption to a heavy soil (Terra-Rosa) was predominately to the clay minerals and oxides.