Leaching of sulfentrazone herbicide in soils with different textures

Resumo

The objective of this study was to evaluate the leaching potential of sulfentrazone herbicide through bioindicator plants after the occurrence of natural rainfall in soils with clayey and sandy textures. The experimental design was completely randomized in a 3 x 8 factorial with four replications, with three levels of rainfall (30-40, 60-80 and 100-120 mm) and eight depth of soil profile (0-3, 3-6, 6-9, 9-12, 12-15, 15-20, 20-25 and 25-30 cm). The collections of samples occurred after sulfentrazone application at doses of 800 g ha^-1 and 600 g ha^-1 for the clayey and sandy soils, respectively, and subsequent accumulation of rainfalls. For the collection of soil sam­ples, PVC columns with 30 cm and 15 cm in diameter were introduced in soil profile.  The columns were care­fully removed by digging around him and maintaining the original soil integrity during the collection. Subsequently, the columns were sepa­rated with cross section for the sowing of bioindicator species, sorghum and Bidens pilosa. After sowing, for eval­uations of bioindicator plants in columns, it was adopted range of 0% to 100% of phytotoxicity, at 5, 7, 10 and 12 days after sowing. Leaching of sulfentrazone was dependent on rain accumulation and soil texture. In larger rain accumulations, sulfentrazone can be found deeper in soils of sandy textures. Sorghum was more suitable as bioindicator plant to demonstrate the herbicide presence at greater depths.