Fenologia e produtividade de cultivares de soja em terras baixas na fronteira oeste do Rio Grande do Sul

Abstract

Soybean (Glycine max L.) is the most important crop in Brazil, being sown in all the states of the nation. In Rio Grande do Sul, 5.5 million hectares are occupied by oilseeds, of which 300 thousand hectares are derived from rotation with irrigated rice in the lowlands, in order to reduce monoculture of the grass. However, due to the fact that its cultivation is widespread in highlands, it still lacks information on adaptation, sowing time and development of cultivars in rice growing areas. The objective of this work was to determine the best sowing season, to characterize crop phenology according to different seasons and their reflections on the morphology and productivity of soybean cultivars in the lowlands. The experiment was conducted in the field in the agricultural year 2016/2017, in Itaqui-RS located in the western border of the state, using five soybean cultivars of different maturity groups, NS 4823 RR (GMR 4.8), BMX It launches IPRO (GMR 6.0), TEC IRGA 6070 RR (GMR 6.3), BS IRGA 1642 IPRO (GMR 6.4), SYN 1378 IPRO (7.8) and three sowing dates (04/11/2016, 02/12/2016 and 03/01/2017). The soybean crop reduces the development cycle according to the sowing delay. The highest productivity was obtained with the sowing performed on 04/11/2016. The cultivars, with a group of relative maturity in the range of 4.8 to 6.4, presented the highest yields. The delay in sowing reduces the height of the plants and the height of insertion of the first legume. Soybean cultivation has productive potential in the lowlands, coupled with the breakdown of irrigated rice monoculture.