Corn–Soybean Rotation Economics: The Data Behind “No-Till, No Yield”
- Buz Kloot, Ph.D.
- 7 hours ago
- 3 min read
By Buz Kloot
This research summary expands on our earlier blog, “No-Till, No Yield: Are We Putting Corn Above Soybean Yields?”. After taking a short pause in posting, we realized we still have much more to share on the tillage conversation — and this piece offers a timely refresher before we dive deeper into the economics of rotation and soil resilience.
Background
Our earlier article asked whether focusing on corn yields alone gives a distorted picture of no-till performance. The evidence suggests it does. When soybeans and rotation diversity enter the equation, the economics shift — often in favor of no-till systems.
No-Till Performance in South Dakota and Beyond
At SDSU’s Beresford Research Farm, Pete Sexton and colleagues (2018) tracked 27 years of corn–soybean data under no-till and conventional tillage.
Corn: Conventional tillage outyielded no-till by an average of 6.1 bu/ac.
Soybeans: No-till outperformed by 1.8 bu/ac.
But in 3- and 4-year rotations, the results reversed:
No-till corn exceeded conventional yields by 1.3–1.8 bu/ac.
No-till soybeans gained 1.4–2.5 bu/ac.
These findings demonstrate that as rotation lengths increase, yield gaps close — and often flip in favor of no-till. A University of Minnesota study (DeJong-Hughes & Vetsch, 2007) found similar patterns. Cool years penalized no-till corn by 9.6 bu/ac, while warmer years narrowed that to 4.7 bu/ac. When averaged, these outcomes align with Beresford’s long-term results.
Rotation Diversity Pays
In her 2022 M.S. thesis, Natalie Sturm studied irrigated corn and wheat systems at Dakota Lakes Research Farm. She found that diverse rotations — particularly those including small grains and legumes — improved soil structure, moisture efficiency, and total grain yields. These gains reinforce the conclusion that rotation diversity enhances no-till performance and resilience.
Economics and Farmer Behavior
As Dr. Dwayne Beck of Dakota Lakes puts it: “Farmers vote with their fields.”The persistence of no-till across the Northern Plains is a practical verdict — not a philosophical one. Growers stick with systems that offer a better return relative to risk, and long-term no-tillers consistently report reduced input costs, improved soil water use, and stable yields across variable years.
Looking Ahead
The next question is purely economic:
What does a longer rotation really cost — or save — over time?
Research from Brookings and on-farm trials across South Dakota suggest that extended rotations can actually improve profitability, even when corn takes a smaller share of acres. We’ll explore that in our next post.
References
Beck, D. (n.d.). Unifying Principles: Similarities Among Prairie Ecosystems. Dakota Lakes Research Farm.DeJong-Hughes, J., & Vetsch, J. (2007). On-Farm Comparison of Conservation Tillage Systems for Corn Following Soybeans. University of Minnesota.
Pittelkow, C. M., Liang, X., Linquist, B. A., et al. (2015). Productivity limits and potentials of the principles of conservation agriculture. Nature, 517, 365–368.
Sexton, P., Rops, B., Stevens, R., Williamson, G., & Sweeter, C. (2018). Long-Term Rotation and Tillage Study: Observations on Corn and Soybean Yields – 2018 Season.
SDSU Southeast Research Farm Annual Report.Sturm, N. (2022). It’s Not Just No-Till: Crop Rotations are Key to Improving Soil Quality and Grain Yields at Dakota Lakes Research Farm. M.S. Thesis, South Dakota State University.
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