ALLELOPATHIC POTENTIAL OF STRAW AND WEED COMPETITION IN SOYBEAN

Abstract

The objective of this study was to evaluate the interference caused by competition and allelopathic effect of straw from weed species on soybean (Glicyne max L.). Two experiments were conducted at the experimental station of the Federal University of Tocantins, in Gurupi (11°44'46.5"S 49°03'10.5"W), Tocantins State, Brazil. The design was randomized blocks with four replications and ten treatments: nine weed species. In the first experiment, weeds coexisted with soybean throughout the cycle. And in the second, the plant residues of the weeds were placed on the soil surface. Plant height was analyzed at 30 and 60 days after emergence, first pod height, leaf area, shoot dry matter, number of pods per plant and soybean crop yield. All species have a negative effect on the soybean crop, varying in different intensities of interference. The straws of the weeds did not show an effect on the evaluated traits of soybean.