Sowing dates and spacing on some agronomic characteristics of soybean in the planalto riograndense

Abstract

To study the behavior of three soybean cultivars (Glycine max (L.) Merrill) (Paraná, Bragg and Santa Rosa) in three interrow spacings (40, 60 and 80 cm) and three sowing dates (10.15, 11.15 and 12.15) during the period 1976/77 through 1979/80 an experiment was conducted at the Centro Nacional de Pesquisa de Trigo (National Wheat Research Center), in Passo Fundo, RS, Brazil. The experimental lay-out was in randomized complete block design with split-plots and three replications. Spacings showed no effects on grain yield, plant height, and lowest pod insertion, independently of year, date, and cultivar. The performance of cultivars in all dates was highly influenced by environmental conditions prevailing in each year. On the average, during the four years, the second sowing date (11.15) showed greater grain yields, plant height, and insertion of  lowest pods. Yield of cultivar Santa Rosa in the three dates showed great stability, varying just 1.1% as compared to 45.6% and 27.2% obtained with Paraná and Bragg, respectively.