Effect of Seeding Density on the Growth and Yield Characteristics of Soybean

Soybean (Glycine max L.) is a critical global crop, yet its productivity is often constrained by suboptimal planting practices, particularly seeding density. This study empirically investigates the impact of four seeding densities (200k, 300k, 400k, and 500k plants/ha) on the growth and yield of soybean in Chipata District, Zambia, using a Randomized Complete Block Design. Surveys of 99 farmers revealed that 64% rely on personal experience to set density, with 70% using a suboptimal range of 50,000-70,000 seeds/ha, primarily influenced by soil type (35%) and expected rainfall (25%). Field experiments demonstrated that increasing density from 200k to 400k plants/ha significantly enhanced key metrics: plant height by 18%, leaf area by 22%, and most critically, average yield by 31% (from 1,150 kg/ha to 1,510 kg/ha). However, a diminishing return was observed at 500k plants/ha. ANOVA results confirmed that seeding density was a statistically significant factor in yield variation (F-statistic = 25.0, p < 0.05). The study concludes that an optimal seeding density of 400,000 plants/ha maximizes yield in the studied agro-ecology, providing a clear, evidence-based recommendation to bridge the gap between common farmer practice and scientific optimization for enhanced productivity and resource efficiency.