Soybean cultivars subjected to narrow row spacing and plant populations in early sowing in subtropical region in southern Brazil
Cultivares de soja submetidas ao espaçamento reduzido e populações de plantas em semeadura antecipada em região subtropical no sul do Brasil
Keywords:Glycine max L. Merrill, early sowing date, seeding density, 25-cm row spacing
Spatial arrangement between plants and sowing time used are decisive practices for obtaining adequate agronomic performance in soybean crop. The aim of this work was to evaluate morphological attributes, yield components and grain yield of soybean cultivars installed with different row spacing and seeding densities, in early (10/04/2017) and conventional (11/08/2017) sowing dates in subtropical climate region in southern Brazil. The experimental design was in a 2×2×4 factorial arrangement: soybean cultivars BRS 433 RR (MG 5.8) and BRS 1003 IPRO (MG 6.3) installed with row spacing of 25 and 50 cm and seeding densities of 160,000; 240,000; 320,000; and 400,000 viable seeds ha-1. Morphological attributes and yield components are altered by spatial arrangement between plants and cultivar, with variable responses according to the sowing date. In the early sowing date, soybean has yield raise due to the increase in seeding density with different responses between cultivars. In the conventional sowing date, soybean installed with 25-cm row spacing has an increase in 1000-grains weight. In the conventional sowing date, there is an increase in soybean yield installed with 25-cm row spacing associated with a seeding density of 320,000 to 400,000 viable seeds ha-1.