Aplicação de glifosato e manganês na nutrição e produtividade da soja transgênica

Abstract

The transgenic glyphosate-resistant soybean (soybean GR) has been widely cultivated in the world. Although of the benefits of this technology on weed control, currently observed at some regions that, after the application glyphosate, the soybean GR were with leaf chlorosis and could be caused by glyphosate-induced deficiency of Manganese. Thus, the objective of this study was to evaluate the post-emergence application of glyphosate and Mn on soybean GR at different phenological growth stages and your effect in nutrients uptake and soybean GR yield. The experiment was carried out at two farms (Lages de Pedra and São Manoel), both at city of Rio Brilhante-MS. The study was in a completely randomized block design with four (São Manoel) and six (Lages de Pedra) replicates. The treatments were analyzed as factorial 3x8 with three times of application (without glyphosate; glyphosate application (720 g e.a.) in phenological growth stages V2 + V4 (480 g e.a.) and application only V4 (1.200 g e.a.)) and eight foliar Mn application of Mn in different phenological growth stages (without Mn; Mn on V4; Mn on V4 + V8; Mn on V4 + R2; Mn on V4 + V8 + R2; Mn on V8; Mn on V8 + R2 e Mn on R2), completing 24 treatments. It was not observed at no moment of the development of the culture visual symptoms of plant toxicity effects caused by glyphosate application. As well, it was not observed effects of glyphosate application on soybean GR in uptake of Mn and nutrients as N, P, K, Fe, Zn e Cu, as well, in mass of 100 grains and yield culture. The foliar Mn application did not influence the mass of 100 grains and yield culture, however increased leaf Mn content when the application was carried at phenological growth stages V8 and R2 or inside these possible combinations. The leaf Fe content decreased with the foliar Mn application.