Datas de semeadura e grupos de maturidade relativa de soja adaptados a terras baixas na fronteira oeste do Rio Grande do Sul

Abstract

In the middle south of Rio Grande do Sul, Brazil, 1.5 million hectares are cultivated with soybean, in which 280,000 hectares are in rotation with irrigated lowland rice. Traditionally grown in upland regions of RS, soybean is intolerant to poorly drained soils, and it is necessary to realize specific management operations, such as drains and drainage channels, so that water infiltrates and does not stagnate in the soil. The objective of this work was determining the main sowing dates and the characterization of soybean maturity groups to lowland in the west border of Rio Grande do Sul. The field experiment was conducted with soybean during the 2016/2017 growing season, in Itaqui, next to the commercial farming in Agropecuária Busato. It was consisted by five soybean cultivars of different maturity groups, NS 4823 RR, BMX Lança IPRO, BS IRGA 1642 IPRO, TEC IRGA 6070 RR, SYN 1378 IPRO and three sowing dates (11/22/2016, 12/14/2016 and 01/12/2017). The highest grain yield was obtained on 11/22/2016. The cultivars with maturity group ranging of 6.0 to 6.4 presented the largest yields. RS soils traditionally cultivated with irrigated rice, since well-managed, have the potential to produce good soybean yields.