As soybean prices become increasingly tied to crop quality, not just yield, research from Southern Illinois University suggests that farmers could benefit from site-specific management strategies that account for both productivity and nutritional value. 

With funding from the Illinois Soybean Association checkoff program, Dr. Jay Nair and his team examined how soil characteristics, seeding rates, and the use of biologicals affected not just yield, but the soybean meal value (SBM)—a key factor in how processors determine pricing. 

Illinois soybean growers face a yield gap of up to 46 bushels per acre, driven by differences between potential and actual on-farm yields. Within individual fields, yield variability can be influenced by a mix of soil conditions, compaction, and nutrient availability—factors that standard uniform management often overlooks. 

In this study, researchers broke three 10-acre fields into low-, medium-, and high-yield zones and implemented three treatment strategies: 

• Uniform seeding with no biologicals (140,000 seeds/ac) 

• Variable-rate seeding with biologicals (180,000 seeds/ac for low, 160,000 seeds/ac for medium, and 140,000 seeds for high-yield zones) 

• Uniform seeding with biologicals (140,000 seeds/ac) 

All other management practices were held constant. 

Photo provided by Illinois Soybean Association

What the Data Showed:

• Soil Matters, But It’s Not Static: Interestingly, previously low-yield zones showed improved nutrient levels, pH, and organic matter, indicating that soil productivity can change over time with management, erosion, and environmental conditions. 

• Biologicals Boosted Meal Value: Fields where biologicals were applied (regardless of seeding rate) delivered the highest soybean meal values, driven by improved crude protein and amino acid composition—both of which impact processor pricing. 

• Soybean Meal Value Varied Widely: Across treatments, SBM value ranged from $300 to $330 per tonne—a spread that could translate into meaningful price gains for farmers focused on quality. 

• Soil moisture, electrical conductivity, and nitrogen release were also higher in areas that had previously been low yielding, suggesting changing zones may merit more attention, not less. 

In a marketplace where soybean processors reward higher quality, farmers have a chance to earn more—not just by increasing yield, but by improving the meal value of their soybeans. Site-specific management, particularly when paired with biologicals, offers a promising pathway to capture that added value. 

For farmers, this research reinforces that not all yield zones are created equal, and they can shift over time. Managing them differently through site-specific practices can lead to measurable gains. The use of biologicals may provide dual benefits by improving nutrient uptake and enhancing soybean meal value. Additionally, combining precision seeding with targeted nutrient management can help close the yield gap while boosting crop quality. As soybean markets continue to evolve, farmers who focus on both yield and compositional quality may be better positioned to capture premium prices. 

For a full description of this Illinois Soybean Association checkoff funded project, visit Field Advisor’s Research Hub.