Growth suppression of sandspur grass by cover crops1

ABSTRACTSandspur grass has hindered the integrated weed management in the Brazilian crop systems. This study aimed at evaluating the efficiency of biomass levels of different cover crops on the soil surface to control the sandspur grass. A complete randomized blocks design with four replications, in a 6 x 5 + 1 factorial arrangement, was used. The first factor consisted of six cover crops (Pennisetum glaucum-ADR 7010 and ADR 300 cultivars, Crotalaria ochroleuca, Urochloa ruziziensis, Fagopyrum tataricum and Crambe abyssinica) and the second one consisted of five biomass levels of each species (2 t ha-1, 4 t ha-1, 8 t ha-1, 12 t ha-1 and 16 t ha-1), plus a control treatment without soil cover. The variables analyzed were the total number of emerged plants, germination speed index, leaf area, root volume and shoot and root dry biomass. U. ruziziensis excelled in the suppression of C. echinatus growth by reducing the number of emerged plants, emergence speed index, shoot and root dry biomass, root volume and leaf area.