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Row Spacing and Plant Population Effects on Yield Components of Soybean

Ethredge, W. J., Ashley, D. A., Woodruff, J. M.
Agronomy journal 1989 v.81 no.6 pp. 947-951
Glycine max, cultivars, row spacing, irrigated conditions, stand characteristics, crop yield, seeds, mortality, harvest index, Georgia
Information is needed to characterize soybean [ (L.) Merr.] plant responses where cultural practices and environmental conditions are maintained at a level conducive to high yield. Field studies were conducted in 1985 and 1986 to determine the effect of row spacing and plant population on seed yield and yield components of soybean. Two determinate Maturity Group V cultivars, Essex and Deltapine 105, were grown at three row spacings of 25, 51, and 76 cm and three plant populations of 260 200, 390 400, and 520 400 plants ha. Seed yield was significantly higher in narrow rows (25 and 51 cm) than in the wide rows (76 cm) with the 25-cm row spacing averaging 10% higher than the 76-cm row spacing (3740 vs. 3361 kg ha). There was a row spacing × cultivar interaction due mainly to a greater reduction in seed yield of Essex than Deltapine 105 as row width increased. Weight of aerial plant parts during the mid seed-fill growth period (R5) increased with decreasing row spacings. Plant number in plots with 76-cm row spacing decreased approximately 23% between planting and harvest whereas, the plant number in 51- and 25-cm row spacings decreased only 7 and 3% respectively during the growing season. Seed yield per plant was most uniform at the 25-cm row spacing and became more variable as row width increased