This work was carried out at the Experimental Station of the University of Tocantins, Gurupi-TO, Brazil, to evaluate the interference of eight species frequently used as green manure (Mucuna aterrima, Mucuna pruriens, Crotalaria ochroleuca, Crotalaria spectabilis, Canavalia ensiformis, Cajanus cajan, Pennisetum americanum and Sorghum bicolor, hybrid BR304) in the weed community, for sixty days under field conditions. The most frequent weed species in the experimental area were Digitaria horizontalis, Hyptis lophanta and Amaranthus spinosus. Samplings were made at 15, 30, 45 and 60 days after formation of green manure covering, using a square sampler of 0.25 m². The weeds were identified, collected, dried and weighed. The experimental design consisted of nine treatments distributed in randomized blocks with four replicates. It was verified that C. spectabilis, S. bicolor, C. ochroleuca M. aterrima and M. pruriens reduced significantly the number and dry matter weight of the weeds evaluated, especially H.lophanta and A. spinosus, while P. americanum was the least efficient.
allelopathy; competition; soil mulch; weeds
