Conservation tillage practices like strip-till and no-till are gaining ground across Illinois as farmers look to improve soil health, reduce erosion, and cut input costs. But for soybeans, these systems sometimes come with a catch—lower yields. 

To address this, a research team led by Dr. Giovani Preza Fontes at the University of Illinois, in collaboration with Southern Illinois University, launched a multi-site study—funded by the Illinois Soybean Association checkoff program—to evaluate how tillage type, row spacing, and starter fertilizer (nitrogen and sulfur) interact to influence soybean growth and yield.

Cool, wet spring soils, especially in corn residue-heavy fields, can delay early soybean development and reduce nutrient availability. In no-till systems, limited early-season mineralization and potential nutrient tie-up can create stress for soybeans during critical growth stages.

This study set out to evaluate how different management tweaks, like applying N and S at planting or switching to narrower rows, might overcome those challenges and help make conservation tillage systems more viable for soybean production. 

Research was conducted at three locations: Fulton, Monticello, and Carbondale. Trials compared: 

• Tillage types: Conventional (CT), Strip-till (ST), No-till (NT), and No-till + cereal rye (NT+CR) 

• Starter fertilizer: None, nitrogen alone ((15 lb N/ac as UAN), and nitrogen + sulfur (15 lb N + 10 lb S/ac as UAN + ATS) 

• Row spacings: 15-inch vs. 30-inch rows 

Key Findings: 

• Strip-till performs as well as conventional tillage across all sites. In some cases, it preserved more soil moisture and showed similar yields to CT. 

• No-till and no-till with cereal rye produced lower yields at Monticello and Carbondale. Slower canopy development and drier summer conditions likely limited grain fill. 

• Starter fertilizer improved yield under conventional tillage at Fulton, but did not impact yield in no-till systems, possibly due to wet spring conditions that improved natural nutrient availability. 

• Narrower rows (15-inch) outyielded 30-inch rows at Monticello. Applying N+S helped 30-inch rows catch up to 15-inch yields—important insight for farmers with fixed-width equipment. 

• No fertilizer response was seen in 15-inch rows, suggesting their quicker canopy closure may reduce stress and improve early growth. 

Strip-till may offer the best of both worlds—delivering yields comparable to conventional tillage while preserving the soil health benefits of no-till. For those using 30-inch rows in long-term no-till systems, applying starter nitrogen and sulfur can help close the yield gap when compared to narrower row spacings. Early planting combined with starter fertilizer appears to be a promising strategy to address early-season nutrient stress common in conservation systems. While no-till continues to provide benefits like erosion control and improved soil moisture retention, it may require adjustments in fertility and row spacing to maintain strong yield performance. 

This was year one of a multi-year project. In 2025, researchers will continue evaluating how these variables interact across growing conditions, with the goal of developing best practices for soybeans in reduced tillage systems—practices that protect soil while maximizing profitability. 

For the latest project update, visit Field Advisor’s Research Hub.