As a result of widespread adoption of treated soybean seed, many farmers now plant soybeans earlier than ever before. In fact, Illinois farmers had 41% of their soybean crop planted by May 2, 2021, compared to the previous five-year average of 14%.1
The study presented below was conducted in order to understand the yield impact of planting soybeans at different dates along with the agronomic characteristics that enable early planted soybeans to have higher yield potential.
The main factor behind the yield potential increase in early planted soybeans is the ability for the plants to create more nodes before flowering.2 To better understand this interaction, we measured the number of nodes created and days to flowering.
1 U.S. Department of Agriculture National Agricultural Statistic Service. https://www.nass.usda.gov/Statistics_by_State/Illinois/Publications/Crop_Progress_&_Condition/
2 Bastidas, A.M., Setiyono, T.D., Dobermann, A., Cassman, K.G., Elmore, R.W., Graef, G.L. and Specht, J.E. 2008. Soybean sowing date: The vegetative, reproductive, and agronomic impacts. Crop Science. Volume 48.
3 Hu, M. and Wiatrak, P. 2012. Effect of planting date on soybean growth, yield, and grain quality: review. Agronomy Journal. Volume 104.
4 Rees J. and Specht, J. 2020. Understanding the soybean germination process for early planted soybean decisions. https://cropwatch.unl.edu/2020/understanding-soybean-germination-process-early-planted-soybean-decisions