Effects of ground cover from branches of arboreal species on weed growth and maize yield1 Efeitos da cobertura do solo com ramos de espécies arbóreas no crescimento das plantas daninhas e rendimento do milho

Cultivating maize under systems of alley cropping results in improvements to the soil, a reduction in weeds and an increase in yield. Studies using ground cover from tree shoots produce similar results. The aim of this study was to evaluate the effects on weed growth and maize yield of ground cover made up of 30 t ha-1 (fresh matter) of branches from the tree species: neem (Azadirachta indica A. Juss), gliricidia [Gliricidia sepium (Jacq.) Kunth ex Walp.], leucaena [Leucaena leucocephala (Lam.) de Wit.] and sabiá (Mimosa caesalpiniifolia Benth.). Two treatment groups (cultivars and weed control) were evaluated. The cultivars AG 1041 and AL Bandeirantes were subjected to the following treatments: no hoeing, double hoeing, and ground a cover of branches of the above species when sowing the maize. A randomised block design was used with split lots (cultivars in the lots) and ten replications. The cultivars did not differ for green ear or grain yield. Double hoeing was more effective than ground cover at reducing the growth of weeds. However, both weeding and ground cover resulted in similar yields for green ears and grain, which were greater than those obtained with the unweeded maize.