Avaliação residual da mistura dos herbicidas sulfentrazone+diuron no solo

Abstract

Weeds cause significant losses to agricultural production, and the use of herbicides is one of the main control strategies. However, the persistence of these products in the soil may result in undesirable residual effects. Therefore, the present study aimed to evaluate the residual effect of the sulfentrazone + diuron herbicide mixture in the soil over time at different application rates and soil textures, seeking to understand its persistence and impacts on subsequent crops. The experiments were conducted under field and greenhouse conditions in the municipality of São João Evangelista–MG, using sorghum (Sorghum vulgare) as a bioindicator plant. The evaluated rates were (175+350), (350+700), and (525+1050) g ha⁻¹ of the active ingredients of the herbicides, with soil samples collected at depths of 0–10 and 10–20 cm, from 3 to 273 days after application (DAA). The results indicated that phytotoxicity and the reduction of sorghum dry matter increased with increasing rates and were more persistent in clayey soil, with effects observed up to 273 DAA at the highest rate. In sandy soil, greater herbicide mobility was observed, with intoxication symptoms detected in deeper layers, influenced by the accumulated rainfall of 246 mm. Chromatographic analyses confirmed the remaining presence of the herbicides throughout the soil profile. It was concluded that the residual behavior of the sulfentrazone + diuron mixture is strongly influenced by the applied rate and soil texture, resulting in greater persistence and retention in clayey soils and a higher leaching potential in sandy soils.