Southeast Research and Demonstration Farm
Soybean yields tend to increase with rising plant populations. 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 risen tremendously over the last couple of years. My hypothesis is that seeding rate cost can be reduced if replanting a field is advantageous because soils are warmer and seeding mortality is 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" (2005). Iowa State Research Farm Progress Reports. 1291.