Diferentes doses de herbicidas para o manejo de supressão da pastagem de Estrela africana em pré semeadura do milho na integração lavoura­ pecuária

Abstract

Faced with the growing use of the crop­livestock integration system in the Brazilian scenario, it is important to carry out an efficient management of this system, becoming increasingly representative worldwide. For that, it is necessary, studies about the benefit of these consortia, mainly integrating pastures x annual crops with the animal component. In this context, the work was carried out with the objective of evaluating the reestablishment of the African star forage under different doses of diquat and glyphosate herbicides as well as the productivity of maize in intercropping. The experiment was carried out at the Experimental Farm of UTFPR. The design was completely randomized with 11 treatments and four replications. The treatments were composed of doses of glyphosate herbicide (T1=720 g a.i./ha, T2=1080 g a.i./ha, T3=1440 g a.i./ha, T4=1800 g a.i./ha) and diquat herbicide (T5=200 g a.i./ha, T6= 400 g a.i./ha, T7=600 g a.i./ha, T8= 800 g a.i./ha). Treatment T9 did not have herbicide application (dose 0) and treatments T10 and T11 used glyphosate at a dose of 2500 g e.a./ha (T10) and 1800 g e.a./ha (T11) applied in the corn row. Data were submitted to analysis of variance and 5% tukey test by the Statistical Analysis System (SASacademic version). The variables evaluated were the degree of phytotoxicity and green mass for forage, and plant height at 40 and 85 days, ear insertion height, thousand grain weight and corn yield. Data evaluation showed that there was suppression of forage with the use of herbicides, with greater effect with the use of glyphosate at a dose of 1800g e.a/ha (T4). The use of herbicides had little effect on corn yield, and the highest yield was observed using glyphosate at a dose of 2500 g a.e./ha.