Relationship between Phosphorus Accumulation and Dry Matter Production in Soybeans

Six cultivars of soybean were cultivated under various phosphorus (P) application levels, in pots and in fields to clarify the relationship between P accumulation and dry matter production, and that of varietal differences in soybeans. Dry matter production and yield components increased with the increase of P application, especially under P-deficient conditions, and there were varietal differences in dry matter production, yield components, and amount of P accumulation. However, there were significant relationships between dry matter production and P accumulation, and the relationships could be represented by the same regression line regardless of cultivar. There were varietal differences in dry matter production efficiency of accumulated P under a P-deficient condition. These results suggest that either high ability to accumulate P or efficient dry matter production of P is required for stable production under P-deficient conditions. Therefore, selection of cultivars that have high dry matter production efficiency or large root systems, or the development of agricultural management technology that increases the rate of P fertilizer absorption is required for stable production under P-deficient conditions.