Analysis of the Carbon and Nitrogen Limitations to Soybean Yield1

Abstract Soybeans are hypothesized to be “self‐destructive” since they apparently need to translocate large amounts of nitrogen from vegetative tissues during seed‐fill to sustain seed growth. To assess the possible limitations of this characteristic on soybean seed yield, a simple, dynamic simulation model is developed which accounts for the availability of nitrogen and photosynthate within the plant. The simulations show that the duration of seedfill and seed yield is clearly limited by the self‐destructive characteristic. Increased availability of nitrogen within the plant is required for significant increases in soybean yields. Possible alterations of the model required to mimic actual soybean seed growth are presented.