LEACHING POTENTIAL OF IMAZETAPYR + FLUMIOXAZINE SUBJECTED TO DIFFERENT PRECIPITATION SIMULATIONS

Abstract

In Brazil, herbicides are used to control weeds in order to ensure high soybean yields. However, due to their leaching into the soil profile, herbicides can cause contamination of the soil and groundwater. The objective of this study was to evaluate the influence of rainfall on the leaching of imazethapyr + flumioxazine in dystrophic red-yellow Latosol. The test consisted of applying imazethapyr + flumioxazin (172 + 60 g a.i. ha^-1) at the recommended dose of 0.6 L ha^-1 of the commercial product. The treatments were arranged in a 10 x 4 factorial design, with ten depths (0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45, and 45-50 cm), evaluated within four irrigation rates (0, 30, 60, and 90 mm). The evaluations were performed 7, 14, and 21 days after the application of the treatments. Cucumber (Cucumis sativus L.) was used as a bioindicator plant, sown along the columns. Greater severity of phytotoxicity was observed at higher rainfall levels. For the height variable, rainfall levels of 60 and 90 mm were more harmful to plant development, and for dry mass, a significant difference occurred only at a rainfall level of 0 mm. It was concluded that the herbicide evaluated tends to be leached by rainfall or artificial irrigation, in which this movement in the soil profile can determine the efficiency of weed control, as well as the potential for groundwater contamination.