Western Research and Demonstration Farm
Soybean genetics are changing yearly with improved yield and/or resistance capabilities. Additionally, small plot research from Iowa State University indicates a planting recommendation of April 20 or as soon as soil and weather conditions are suitable at populations of 125,000 to 140,000 seeds/acre. This trial was designed to demonstrate this recommendation on a local site with local conditions.
Iowa State University
Licht, Mark A., "Soybean Planting Dates and Populations" (2009). Iowa State Research Farm Progress Reports. 636.