Over the past three years, researchers from the University of Nebraska-Lincoln and University of Wisconsin-Madison collected survey data from producer soybean fields planted in four growing seasons (2014 to 2017) in Nebraska and nine other states in the region — Wisconsin, Michigan, Indiana, Illinois, Iowa, North Dakota, Ohio, Kansas and Minnesota.
The work was led by University of Nebraska-Lincoln associate professor of agronomy and cropping system specialist Patricio Grassini and University of Wisconsin professor of agronomy and state soybean and small grain specialist Shawn Conley.
The research was supported by the North-Central Soybean Research Program, the Nebraska Soybean Board and the Wisconsin Soybean Marketing Board.
The goal was to identify key management practices explaining the gap between current yield and yield potential as determined by climate, soil and genetics.
This information can help producers understand what factors are preventing them from fully realizing the potential of their soybean fields and fine-tune their management to increase yield and profit.
The UNL-WU team collected data on soybean yield and management practices from 9,133 fields across the north-central U.S., including 2,447 Nebraska fields (irrigated and dryland). UNL researchers partnered with Nebraska Extension and the Nebraska Natural Resources Districts to reach out to producers to take the surveys.
1. Researchers found that the average yield gap (the difference between potential and current yield) in Nebraska ranged from 11% in irrigated fields in south-central Nebraska to 21% in dryland fields in eastern Nebraska.
2. They found that planting date is the most consistent management factor explaining the current yield gap. Delay in planting date after late April leads to a yield penalty of about one-quarter bushel per acre per day in both dryland and irrigated fields. Foliar fungicide application and tillage were other practices explaining the yield gap.