Sowing periods, agronomic performance and seed quality of soybean cultivars in the Planosol soil

Understanding of sowing in an ideal season for each region and cultivar is essential for the crop to reach each of its stages in more favorable climatic conditions. The objective of this study was to evaluate the influence of different sowing times on agronomic attributes of two soybean cultivars and the physiological quality of soybean seeds in soil type Eutrophic Haplic Planosol. The experimental design was completely randomized, in a factorial scheme 4 x 2, with four sowing times and two soybean cultivars, with eight replications. The sowing was executed at the beginning and end of November (1st and 2nd epochs) and beginning and end of January (3rd and 4th epochs), using the cultivars: Fundacep 64 RR and BMX Potência RR. The experiment was carried out in polyethylene vessels with volumetric capacity of 10 liters. The morphological attributes of the plants were evaluated, such as: height, stem diameter, number of pods and seeds per plant, 1000 seed weight, as well as seed germination and vigor. Seeding after January 1st negatively affected the agronomic behavior of soybean plants, with reduction of plant height, stem diameter, number of pods and seeds per plant. The sowing on November 1st favored the obtaining of seeds with lower physical quality in terms of 1000 seed weight; however, seeds with superior physiological performance. Late sowing showed an alternative for the production of soybean seeds in the South region of Rio Grande do Sul, mainly due to the higher quality of the seeds produced in this period.