Época de aplicação de dessecantes em pré-emergência na soja convencional

Abstract

-The weed management in soybean cultures stands out as an important tool to ensure its high yield potential. The direct tillage advent increased the importance of management performed in the soybean off season and pre-seeding, in order to avoid the weeds interference in the initial cultivation period. The survey was conducted in order to evaluate the weeds control and the agronomic performance of conventional soybean, using different desiccant herbicides. The experiment was conducted in randomized blocks design with four replications. Treatments were arranged in factorial 4x3, the first factor being the glyphosate herbicides applicationdiisopropylamine salt; glyphosate -potassium salt, glyphosate isopropylamine-salt + 2,4-D; and paraquat + diuron, the second factor the application time periods (13 and 7 days before seeding -DBS; and 1 day after seeding -DAS). The percentage of weed control, booth, seedling emergence, plants height, number of pods, mass of hundred seeds and productivity were evaluated. Only the management desiccation with glyphosate near the seeding time showed a decrease in the weeds control percentage, the glyphosate + 2,4-D use led to a decrease in the early crop growth, due to seeding proximity, the paraquat + diuron application near the seeding season caused a lower insertion of the first pod in the culture. There were no significant differences between treatments for soybean production components under these experimental conditions.