EFEITO DE SUBDOSES DE HERBICIDAS NA SUPRESSÃO DE Urochloa sp. EM CONSÓRCIO COM A CULTURA DO MILHO

Abstract

The intercropping of second crop corn with Urochloa species is an important alternative to increase and maintain straw on the soil surface, with sufficient quantity to express the potential of the no-tillage system, such as forage to increase the input of plant residues and provide greater economic return on crops that will be sown in succession. The fact that two species germinate and emerge at the same time can, in some situations, generate interspecific competition, causing significant reductions in the productive potential of the main crop. This study aimed to evaluate subdoses of two herbicides in two forages, to verify the efficacy in suppressing forages in order not to compete with corn. The herbicides evaluated were glyphosate and ammonium glufosinate and forages Urochloa brizantha cv. Marandu and Urochloa ruziziensis in doses: 0, 30, 60, 90 and 120 ml ha-1 of commercial products liberty link and roundup transorb. For that, an experiment was carried out in a completely randomized design in the greenhouse of the Federal Institute of Goiás Campus Urutaí, Goiás. The parameters used to evaluate the effectiveness of the products were phytotoxicity and dry matter. The ammonium glufosinate at the doses evaluated caused greater phytotoxicity, however, its dry mass was greater compared to the control, thus it escaped its initial objective. At the doses evaluated, glyphosate was not efficient in reducing the development of forage. It is suggested that further work be carried out using higher doses to evaluate the herbicide for this purpose.