Effect of Plant Spacing on Growth and Grain Yield of Soybean

Abstract

In the Philippines, rice monoculture systems are common. Compared to these systems, the rice-soybean cropping sys tem may prove more water-efficient and there is a trend of increasing soybean area in the response to water scarcity and need for crop diversification in the Philippines. A field study was conducted to evaluate the effect of row and plant to plant spacing (20 × 10, 20 × 5, 40 × 10, and 40 × 5 cm) on growth and yield of soybean. Plant height was not influ enced by the plant geometry. Spacing, however, influenced leaf area and shoot biomass of soybean. Plants grown at the widest spacing ( i.e ., 40 × 10 cm) produced lowest leaf area and shoot biomass at 6 and 12 weeks after planting. Leaf area and shoot biomass at other three spacing were similar. There was a negative and linear relationship between weed biomass and crop shoot biomass at 6 and 12 weeks after planting. Grain yield of soybean was not affected by plant ge ometry and it ranged from 1.3 to 1.9 t·ha - 1 at different spacing.