Análise residual do herbicida sulfentrazone no solo

Currently, weeds cause serious damage to Brazilian agriculture, affecting all phases from planting to harvesting. Lack of control over specific weeds can compromise the quality of the final product, resulting in significant losses. The most widely used method for controlling weeds is chemical control, mainly due to its greater effectiveness in heavily infested areas. Therefore, the objective of this study was to evaluate the residual effect of sulfentrazone, recommended for pre-emergence application in eucalyptus, soybean, and sugarcane crops, considering the interactions between the applied dose, soil texture, and depth. The first factor evaluated was the herbicide dose, with doses of 0, 250, 500, and 750 g ha⁻¹ of the active ingredient sulfentrazone applied. The second factor of the experiment refers to the soilsampling depths: 0 to 10 cm and 10 to 20 cm. To determine the residual period of the herbicide, a bioassay was used with Sorghum vulgare as the indicator plant. At 93 days after application (DAA), a chromatographic analysis was performed to quantify herbicide residues. Sorghum vulgare plants showed variations in intoxication and biomass distribution depending on the herbicide, soil type, and applied dose, especially in sandy soil. The analysis concluded that the herbicide sulfentrazone exhibits significant persistence in different soil types, causing injury to bioindicator plants for up to 273 days after application (DAA), particularly in the 0-10 cm layer of sandy and clayey soils. In the 10-20 cm layer, these injuries were recorded between 63 and 93 DAA in sandy soil, while in clay soil the damage began at 63 DAA and persisted until the end of the evaluation period. Analysis of the amounts of sulfentrazone remaining at 93 DAA indicated that, in sandy soil, the values recovered at doses of 250, 500, and 750 g ha-1,distributed in the 0-20 cm layers, were 59.3 g ha-1; 137.5 g ha-1 and 206.5 g ha-1, respectively. In clay soil, the values found for the same doses and layers were 65.5 g ha-1; 110.9 g ha-1 and 185.1 g ha-1, respectively. These data highlight the need for careful management of sulfentrazone, taking into account its high persistence in the soil and its potential to cause damage to plants over time.