Interference of sorghum, braquiaria and pearl millet cover crops on maize and weeds / INTERFERÃNCIA DE PALHADAS DE SORGO, CAPIM BRAQUIÃRIA E MILHETO SOBRE CULTURA DO MILHO E PLANTAS DANINHAS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

This work aimed to evaluate the effect of forage grass cover crops on corn (Zea mays), weed infestation and floristic weed composition. The treatments were three cover crops: Braquiaria (Brachiaria brizantha); pearl millet (Pennisetum glaucum) and inter specific sorghum hybrid BRS 800 (Sorghum bicolor x Sorghum sudanens) submitted to one cut 60 days after planting and not submitted to cutting. A fallow land was used as check. The experiment was conducted at Embrapa Milho e Sorgo Research Center, Sete Lagoas, MG, Brazil from March 2006 to February 2007. Braquiaria reduced the corn initial stand but there was not significant difference in the final stand. Plant and ear height were significantly different among treatments. Corn stalk diameter under pearl millet was lower than under other cover crops. There were no significant differences among treatments related to corn agronomic characteristics and grain yield. The cutting did not affect the corn agronomic characteristics and grain yield. No differences were verified between the treatment means and the fallow land. The reduction of weed infestation by the cover crops was relevant. Braquiaria mulch reduced the weed infestation more than the other cover crop mulches at 30 DAP, however at 60 DAP it did not differ from pearl milett. The cutting did not show any significant differences in the weed suppression. Straw volume had significant difference among species. The cutting in the cover crops was not significant. The braquiaria mulch volume was superior to those produced by sorghum and pearl milett. The main species observed, representing about 90 % of all weed community, were Leonotis nepetifolia, Digitaria horizontalis, Richardia brasiliensis, Amaranthus retroflexus, Cyperus rotundus and Ageratum conyzoides. The phytosociological parameters showed that the specific composition and weed population densities were affected by the especies of the cover crops. No differences were verified between sorghum and millet means and the fallow land on species diversity, but the populations of the majority of the species were higher in the fallow land. Smaller number of infestant species was observed in the treatment with braquiaria, as well as inferior values of density and abundance of the present species.

ASSUNTO(S)

cobertura morta,gramÃneas forrageiras, plantas daninhas. fitotecnia mulching,forage grass cover crops,weeds

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