Allelophathy of green manures on common bean plants (Phaseolus vulgaris L.

Abstract

This study aimed at evaluating the allelopathic effect of species used as cover crops in no-tillage system on common bean crop. It was conducted in the greenhouse and at the Seed Analysis Laboratory in the Agricultural Department of the Federal University of Lavras, Brazil. The cover crop species used in the experiment were sunn hemp, jack bean, pigeon pea, black oat, sorghum and millet, with and without intercropping, with their straws collected at the early grain filling stage. The aqueous extracts of 5% and 10% (w/v) obtained from those straws were placed in plastic boxes (Gerbox®-type) containing common bean seeds. The straws were also laid on the substrate surface sown with common bean in plastic pots and installed in the greenhouse for chemical and physical effects evaluation of the cover crops. Considering most of the variables studied, it was not verified any damage by either using of mulch or by applying allelopathic extracts. When used as mulch or when applied as aqueous extracts, residues from the intercropping between sunn hemp and sorghum positively affected the common bean plant, benefiting its initial growth.