By Jamie Martin
A recent study from the University of Illinois highlights both the benefits and trade-offs of corn-soybean crop rotation in the Midwest.
The research, led by the Agroecosystem Sustainability Center, found that rotating corn after soybeans boosts yields and reduces nitrogen needs, though it impacts soil carbon levels and nitrogen leaching.
Corn planted after soybeans showed an average yield increase of 6.4% at standard nitrogen rates.
The researchers explained that soybean residue decomposes quickly, warming the soil and helping microbes release nitrogen — similar to using starter fertilizer.
However, when nitrogen application rates were increased, this rotation benefit faded. “The more nitrogen you add, the less yield benefit you get from rotation,” said study author Ziyi Li.
The rotation also reduced soil emissions of nitrous oxide and ammonia. Yet, it led to lower soil organic carbon compared to continuous corn. Soybeans contributed to nitrogen leaching during corn years, as decomposed residues released nutrients into the soil.
“These results underscore a key trade-off,” said Kaiyu Guan. “Rotation improves some sustainability metrics while compromising others, especially under typical fertilization practices.”
Economically, corn-soy rotation provided up to $458 per acre more than continuous corn, particularly at lower fertilizer rates. However, higher corn prices or more nitrogen use could offset these gains.
Experts say farmers must balance soil health, profits, and environmental goals. “Our work gives farmers and policymakers a more holistic view of organic matter, nitrogen, and yield outcomes,” said Andrew Margenot.
The study, funded by several organizations including USDA and NASA, stresses the need for smart nitrogen use and informed crop planning to ensure long-term agricultural sustainability.
Photo Credit: usda
Categories: National