Eficácia e custo de herbicidas pós-emergentes para controle de plantas daninhas no pré- plantio da soja

Abstract

Herbicides are widely used products to eliminate weed competition before soybean planting, ensuring better conditions for crop development. However, the cost can vary significantly, depending on the formulation, efficacy and area to be treated. The choice of the ideal herbicide should balance efficiency in weed control and economic viability. Therefore, the objective of this study was to evaluate the efficacy of herbicide mixtures for pre-planting soybean against difficult-to-control weeds and to determine the costs of the products. The experiment was carried out in Uberlândia - MG. The experimental area was divided into 4 blocks containing 6 plots with 15 m² (5 x 3 m). The treatments were randomly distributed within the blocks. The following tank mixtures were tested: control (no herbicide application); Glyphosate + Clethodim (1440 + 192 g ha-1); Glyphosate + 2,4-D (1440 + 536 g ha-1); Glyphosate + Ammonium Glufosinate (1440 + 400 g ha-1); Glyphosate + Carfentrazone (1440 + 30 g ha-1); Diquat + Carfentrazone (300 + 30 g ha-1). The results suggest that the combination Glyphosate + Carfentrazone appears to be an ideal choice due to the balance between cost and effectiveness. The statistical analysis reinforces the importance of considering the post-application time and the mechanism of action when choosing the herbicide, since there were significant differences between treatments and over time (p < 0.01). In summary, success in chemical weed management depends on a combined strategy that considers both the biology of the target species and the pharmacodynamics of the herbicides used..