Urochloa spp IMPLANTADA EM SOBRESSEMEADURA NA CULTURA DA SOJA EM MANEJOS DE HERBICIDAS E TAXAS DE SEMEADURA

Abstract

The objective was to evaluate the residual effect of diclosulam and sulfentrazone applied to soybean crops on the establishment and bromatological quality of Urochloa genus pastures overseeded on the legume. An experiment was carried out in the southern Amazon region in Guarantã do Norte-MT. The experimental design was in randomized blocks, in a 3x3 factorial arrangement, with 3 repetitions. Three forage species, BRS Xaraés, BRS Ipyporã, and BRS Piatã, and three management strategies with herbicides applied to soybean crops were evaluated: control with glyphosate application (960 g a.i. ha-1); diclosulam (35.3 g a.i. ha-1); sulfentrazone (200 g a.i. ha-1). After sowing and cultivating the soybean crop, the pastures were overseeded at a rate of 4 kg.ha-1 when the legume was at the R.6 stage. The number of eudicotyledonous and monocotyledonous weeds and forage materials, crop productivity, forage dry matter, leaf dry matter, stem dry matter, leaf-stem ratio, crude protein, neutral detergent fiber, and acid detergent fiber were evaluated. BRS Ipyporã showed a higher number of plants per m². The management with the pre-emergent herbicides significantly interfered with the control of eudicotyledonous weeds. The productive and bromatological characteristics of the forage were not significantly altered by the treatments tested. The BRS Piatã, MG5, and BRS materials showed good adaptability to the overseeding implementation system. Neither diclosulam nor sulfentrazone significantly harmed the pastures.