Manejo de plantas daninhas em milho submetido ao dano mecânico

Abstract

Weed management is essential for the sustainability and productivity of the integrated soybean-second crop corn production system. In the early intercropping of corn between soybean rows (Antecipe system), mechanical damage during soybean harvest—such as trampling of corn plants by machinery and contact with harvesters—can lead to changes in weed population dynamics and corn selectivity to herbicides. To understand the interference of these weeds and herbicide selectivity, two experiments were conducted, in which corn plants were subjected to simulated mechanical damage mimicking the effect of harvesters in the Antecipe system. The knowledge generated is crucial to minimizing losses and optimizing chemical control, especially under conditions where corn plants have suffered reduced leaf area due to mechanical stress. The first study was designed to evaluate different technological levels of chemical management on the weed seed bank dynamics over three agricultural years in the soybean-second crop corn system under the Antecipe system, identifying the most relevant species and their seasonal variation. The second study analyzed the selectivity of the herbicides glyphosate, terbuthylazine, tembotrione, and nicosulfuron on corn subjected to mechanical damage, determining the safety of using these products under conditions of mechanical stress caused by harvester passage during soybean harvest. Under the experimental conditions, the herbicides glyphosate, terbuthylazine, tembotrione, and nicosulfuron were selective and proved safe for corn in the Antecipe system when applied at recommended doses. Mechanical damage to corn plants did not alter herbicide selectivity. Weed management using herbicides with six different modes of action is effective in controlling Digitaria insularis. This research contributes to decision-making in production systems under Antecipe system conditions and provides support for agricultural practices aimed at sustainability and maximizing crop yields.