Efeito do sulfentrazone + diuron e diclosulam no controle de plantas daninhas na aplicação sobre palha de cana-de-açúcar e com vinhaça

Abstract

Brazil is the second largest producer of ethanol in the world and the first producer of sugar. Vinasse is a by-product of ethanol production and is used in sugarcane fertigation due to its high organic matter and nutrient content. Pre-emergent herbicides such as sulfentrazone + diuron and diclosulam are applied to control weeds Rottboellia exaltata and Ipomoea grandifolia. The objective of this work was to evaluate the control of weeds R. exaltata and I. grandifolia in areas of raw sugarcane harvesting and vinasse application. The experiment was conducted in a greenhouse, in the horticulture area of the Federal University of Grande Dourados. The experimental design used was completely randomized in a 4 x 6 factorial scheme, with four replications, the first factor being composed of the managements (0 t ha-1 of sugarcane straw with vinasse application; 0 t ha-1 of sugarcane straw without vinasse application; 10 t ha-1 sugarcane straw with vinasse application; 10 t ha-1 sugarcane straw without vinasse application), the second factor represented by the evaluation periods (7, 14, 21, 28, 35 and 42 days after weed emergence (DAE)). This factorial was isolated for the pre-emergent herbicides (sulfentrazone + diuron and diclosulam) and for the two plant species. At 7, 14, 21, 28, 35 and 42 DAE, visual evaluations of phytointoxication were performed based on a visual percentage scale of scores. The data were submitted to variance analysis by the F test, and the means were compared using the Tukey test, using the Agroestat computational statistical program. The application of vinasse did not interfere in the control of R. exaltata through the herbicide sulfentrazone + diuron, but the presence of straw reduced the control of this weed. The herbicide sulfentrazone + diuron provided excellent control of Ipomoea grandifolia regardless of the management employed. Vinasse increased control control Rottboellia exaltata and Ipomoea grandifolia when the herbicide diclosulam was applied.