Initial Development of Soybean as a Bioindicator of the Potential of Leaching 2,4-D In Red Latosol

Abstract

Abstract. The objective of this study was to evaluate the potential of leaching 2,4-D in Red Latosol using soybean as a bioindicator plant, to verify the residual effect of the distribution of the herbicide in the soil on the initial development of the plant. The experimental design is a 5 × 11 × 2 triple factorial model, with 5 treatments of water slides (20, 40, 60, 80 and 100 mm) applied by a rainfall simulator. The depth of 11 layers (0-5, 5 -10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45, 45-50, and 50-55 cm) were mounted on soil columns using two groups (in the absence and the presence of the 2,4-D herbicide dimethylamine by application at a dose of 1500 g a.i. ha-1), with four replicates, making 440 experimental plots. The residual effect of the herbicide was evaluated by seedling emergence speed index, total seedling emergence percentage and plant height evaluation. The results demonstrated that the effect of 2,4-D herbicide distribution along the soil profile induces increases in the initial development of soybean when compared to the control treatment. However, the residual 2,4-D in the soil decreases with 80- and 100-mm sheets that have greater herbicide leaching potential beyond the depth range of the soil columns. Keywords: Residual effect, Seedling emergence, Glycine max.