Effect of Sulfur and Boron Nutrition on Yield and Quality of Soybean (Glycine max L.) Grown in an Acid Soil

Soybean (Glycine max L.), being a leguminous oilseed crop, requires relatively higher amount of sulfur (S) and boron (B) for optimum yield and quality. A field experiment was conducted to evaluate the effect of S and B application on growth, yield, and quality of soybean, and to find out their optimum doses for the best crop performance in acidic soils of northeast India. The treatments comprised four levels of S (0, 20, 40, and 60 kg/ha) and four levels of B (0, 0.5, 1.0, and 1.5 kg/ha) in factorial combination. In general, application of S and B, either alone or in combination, significantly increased the growth, yield, and quality of soybean. When applied alone, S resulted in best yield (1767 kg/ha) at S₄₀, which was 21.2% higher than the yield at control (1458 kg/ha), while B produced maximum yield (1578 kg/ha) at B_1.5 (8.23% higher than control). Interestingly, 57.4% yield improvement over control was recorded with combined application of S₄₀ and B_1.5, which shows their synergistic effect on crop performance. Similarly, with concurrent application of S₄₀ and B_1.5, a 28% increase in protein and 33% increase in oil content of soybean were recorded relative to control. In general, S₄₀ + B_1.5 also resulted in the highest nutrient nitrogen, phosphorus, potassium sulfur, and boron (NPKSB) uptake by soybean. Based on these results, we recommend the conjunctive use of 40 kg S and 1.5 kg B/ha for the best yield and quality of soybean on acidic soils of northeast India and other regions with similar soils.