Effect of predecessor crops to sugarcane on floristic composition of weeds

Abstract

This study, during one year period, dealt with the identification of the floristic composition of weeds in areas of sugarcane production, in Felixlândia, Minas Gerais State (Brazil), in response to predecessor crops to sugarcane planting. The experiment was carried out at the EPAMIG Experimental Farm, in a randomized complete block design with six treatments and four replications, being evaluated the sugarcane variety SP81-3250. The treatments were the predecessor crops to sugarcane: Pennisetum glaucum, Crotalaria juncea, Stizolobium aterrimum, Cajanus cajan and Glycine max, plus a control (degraded pasture of Brachiaria decumbens). The floristic composition was evaluated during the four seasons of the year, being identified 23 weed species distributed in 18 genera and 13 families.  The most representative families were Leguminosae and Solanaceae, with four species, followed by Malvaceae, with three species and two Rubiaceae and Convolvulaceae species. The B. decumbens specie was found in all periods of the year and in all different treatments of predecessor crops to sugarcane during winter and spring seasons. The differences in floristic composition as much to the predecessor cultivations as the evaluated periods become relevant for planning the proper management of weeds in sugarcane crop.