Influência da irrigação suplementar na produção e qualidade de sementes salvas de soja na safra 2021/22

Abstract

Soy is the main spring-summer crop in RS and studies that contribute to increasing its productivity and reducing production costs are of fundamental importance. Thus, this study aims to evaluate the influence of supplementary irrigation on the productivity and quality of saved seeds in soybean cultivars with different GMR's in the 2021-22 harvest in Cachoeira do Sul. The field experiment was installed at the Uergs Agronomic Station in Cachoeira do SulRS. The experimental design was randomized blocks with subdivided plots, in a factorial scheme (4x2), with 4 different cultivars, which are: BMX Raio, BMX Zeus, BMX Garra and NEO 610 and with two water regimes: irrigated and non-irrigated (rainfed), with four replications. Sowing was carried out on November 30, 2021 in the planting system. The irrigation system used was conventional sprinkler activated whenever soil storage reached 40% depletion of the total available water capacity. On April 27, 2022, all plants in the central area of the plots were harvested, productivity (kg ha-1 ), the mass of a thousand seeds (MMS) was determined, and samples were prepared for germination analysis and seed vigor, sent to a specialized (private) laboratory. The agricultural year evaluated for) was characterized by insufficient accumulated rainfall (394 mm) to supply the crop's water demand (456 mm) requiring 14 supplementary irrigations (190 mm). Supplementary irrigation contributed to the increase in soybean productivity by an average of 43%, but did not contribute to the increase in the thousand-seed mass, which was greater in the water regime than in the rainfed regime. Cultivars BMX Zeus and BMX Garra were the most productive in both water regimes with average values of 5231.5 kg ha-1 (irrigated) and 3223.7 kg ha-1 (irrigated). The BMX Garra and NEO 610 irrigated cultivars produced seeds with germination percentages and vigor superior to 80%, indicating their potential use as saved seeds. While, under rainfed production conditions, only the cultivar BMX Garra reached a percentage of seed germination greater than 80%.