If we assume that 60–80% of the Illinois wheat acres are double-cropped with soybeans, that equates to about 500,000 to 700,000 acres of double-crop soybeans grown each year. It is no surprise that many Illinois farmers told the Illinois Soybean Association (ISA) in its annual Soybean Production Concerns survey that they want more agronomic research to maximize wheat and double-crop soybean production. 

The next step was to work with members of the Illinois Wheat Association board to prioritize agronomic research through practical on-farm trials that deliver reliable, actionable results to improve double-crop soybean production in Illinois. The goal of the ISA On-Farm trial Network (OFTN) is to bridge the gap between small-scale university trials, which often lack farmer engagement or broad applicability, and industry trials, which may be biased toward product promotion. 

In 2026, we are asking at least five farmers in Southern Illinois to participate in the ISA OFTN double-crop soybean action trial. The goal is to determine optimum planting populations for wheat/double-crop soybeans based on seed cost and yield. After consulting with several Southern Illinois crop consultants, the following protocol was developed: 

• The farmer is responsible for planting and all management applications in the trial.  

• Plot layout may vary depending on equipment and field dimensions, but each trial must cover at least 40 acres. 

• Farmers must provide planter information and be able to adjust planting populations or use a variable seeding rate if available. 

• The same soybean variety will be planted at three different populations (180,000; 220,000; and 260,000 seeds/acre) for double-crop soybeans after wheat.  

• Each trial will include at least four replications of each population treatment under the same management, for a total of 12 plots, each with a minimum width of 60 feet. 

• The combine must have a calibrated yield monitor to ensure accurate post-harvest yield data.  

Read the full protocol by clicking here.

If you are interested in participating in this on-farm research to analyze the economically optimum planting population for double-crop soybeans on your farm, please fill out the Illinois Soybean Association On-Farm Trial Network Interest Form. If you have questions about participating in this study, contact Deanna Burkhart, Producer and Field Services Administrator, at deanna.burkhart@ilsoy.org or 309-307-9366. 

Qualified farmers participating in ISA's OFTN may be eligible for stipend payments. Program eligibility and payment amounts will vary based on specific guidelines. OFTN is funded by the Illinois Soybean checkoff program.