DISSIPATION OF ACETOCHLOR AND RESIDUE ANALYSIS IN MAIZE AND SOIL UNDER FIELD CONDITIONS

Abstract

Acetochlor is a widespread used herbicide in maize crops; however, the environmental risk of its residues in the soilplant system remains unknown. There was assessed the dissipation dynamics of acetochlor doses and its impact on residue level and microbial activity in soil over a season of vegetation. Since the herbicide was applied to the soil surface, its degradation varies as a dependence of concentration, soil type, pH, organic matter and environmental conditions. The field soil samples extraction in different imposed conditions of depths, time and herbicide application revealed a moving deeper of doses. The increased dose (80%+Rd) affects the persistence of acetochlor in the top layer by increasing its half-life from 14 to 17 days. Dissipation followed a first order kinetics. The diversity of soil microbial community changed after the introduction of acetochlor doses. An evident increase of bacteria and soil microorganisms was observed; however, fungal growth was prone to be inhibited. The higher concentration of herbicide was found to be safe, as well as the residues of acetochlor below maximum residue limits (MRL) at the end of maize crop season.