Intercropping of soybean cultivars with Urochloa

Abstract

The integrated crop-livestock system is a key strategy for both grain and livestock production. The cultivation of grass species in between two soybean cropping seasons has been an important component of this system, in Brazil. Thus, this study aimed to evaluate the yield of glyphosate-resistant soybean cultivars intercropped with Urochloa species, under different forage management systems. A total of six experiments, consisting of three soybean cultivars (BRS 295 RR, BRS 316 RR, and BRS 294 RR) and two grass species (Urochloa ruziziensis and Urochloa brizantha), were established. For each experiment, four treatments (soybean only; grass only; soybean intercropped with a grass species, with the application of glyphosate to decrease the growth of grass; and soybean intercropped with a grass species, without growth suppression) were evaluated in a completely randomized experimental design, with four replications. For each experiment, only one soybean cultivar and one grass species were used. The grasses were sown in the soybean inter-rows at 27 days after sowing (DAS), while the glyphosate application to the treatment with grass suppression was performed at 84 DAS for the soybean or 57 DAS for the grasses. The yields of the three soybean cultivars were not significantly affected by either grass species, even though the shoot dry-matter yields for both of the intercropped grass species were high, though lower than the values obtained without the interference imposed by soybean.