Over the past decade, improvements in soybean genetics, planting technology and weed control systems have led to lower planting rate recommendations for soybean farmers.1
While fungicide use in soybeans is steadily increasing,2 some farmers wonder if fungicide is more beneficial in higher populations that have a higher potential for disease development or vice versa.3
The goal of this research was to determine how planting rate and fungicide application interact and affect yield and disease development in soybeans.
Figure 1. Average yield response of soybean to fungicide application and plant population (2019-2021).
Here are some key takeaways from this study:
1 Pedersen, P. Optimum plant population in Iowa. Iowa State University. https://crops.extension.iastate.edu/files/article/OptimumPlantPop_000.pdf
2 Geisler, L.J., and Miller, J.J. 2017. Managing foliar diseases in soybean. Nebraska Extension. https://extensionpublications.unl.edu/assets/html/g1862/build/g1862.htm
3 Porter, S. 2019. Five reasons to stop your higher soybean population. Illinois Soy Advisor. https://www.ilsoyadvisor.com/on-farm/ilsoyadvisor/5-reasons-stop-your-higher-soybean-population