Southeast Research and Demonstration Farm
Soybean yields often increase, up to a point, with increasing plant population. However, soybean yield responses to plant population are generally small and often inconsistent. In general, when plant populations are increased, plant height increases and there are greater yield losses from lodging. Soybean seed prices have increased tremendously over the last couple of years. Our hypothesis is that we can reduce our seeding rate cost if we need to replant a field because soils are warmer and seeding mortality lower. The objective of this experiment was to determine the optimum plant population across different planting dates using different tillage systems.
Iowa State University
Pedersen, Palle, "Soybean Yield as Influenced by Planting Date and Plant Population" (2004). Iowa State Research Farm Progress Reports. 1410.