The objective of this study was to evaluate the effects of the row spacing reduction, plant populations and soil fertility on soybean potential yield at three stages of development. The experiment was performed at the Estação Experimental Agronômica of Universidade Federal do Rio Grande do Sul, in Eldorado do Sul, Rio Grande do Sul State, Brazil, in the 1996/97 growing season, in a Rhodic Paleudult soil . The experimental design was a split split-plot randomized complete block, with four replicates. Treatments were tested at three soil fertility levels (without fertilization, the recommended fertilization and twice the recommended fertilization), two plant populations (30 and 40 plants m-2) and two row spacing (20 and 40 cm). The cultivar tested was FT-Saray (early), in no-till. Mean potential yields were 15.007 kg ha-1 in R2, 10.282 kg ha-1 in R5 and 5.330 kg ha-1 in R8 (maturity). Plant populations as well as row spacing affected the soybean potential yield. The population of 40 plants m-2 was greater than the 30 plants m-2 in R5 but this advantage was not observed at maturity, because at this stage there was no difference between populations. With 20 cm rows the potential yield was greater than with 40 cm in R5, resulting in higher yield in R8.
Glycine max; developmental stages; yield components; plant population; soil fertility; biological development
