This research was carried out during the growing season 1990/91, in Jaboticabal/SP. It tested the integration between crop practices and lower herbicide doses, sprayed in post-emergence for soybean crop, cultivar Parana. The experimental design was randomized blocks, with sixteen treatments and four replications, in four different weed management systems: infested control; controlled with 50% of the recommended ( 0,75 l pc /ha) bentazon dose; controlled with the recommended bentazon dose (1,5 l pc /ha) and a control kept clean; two spacings between rows: 30 cm and 60 cm; and two densities: normal and reduced (about 20 and 10 plants per meter, respectively). It was observed that the amount of dry matter of the weeds for time of the crop of the soy was significantly larger in the treatments with larger spacing and reduced density. The arrangement provided by the normal density (average of 20 plants /m) and smaller spacing (30 cm) among-lines provided more precocious shady of the soil and it was the best option of control of the weeds in all the tested treatments. It was not observed intoxication symptoms nor negative effects on the nodulation of the soy plants, on the part of the applied herbicide, in both tested doses.
Weed; cultural control; herbicide; Glycine max