Corn After Soy: New Study Quantifies Rotation Benefits and Trade-Offs

By Lauren Quinn

While the majority of Midwestern farmers rotate corn and soybeans, commodity prices and corn yield advantages compel some to plant corn year after year. Although foundational research on the benefits of corn-soybean rotation goes back decades, University of Illinois Urbana-Champaign scientists are working to address remaining holistic questions about crop yield, environmental impacts, and economic returns under various crop rotation scenarios. 

In a new study, researchers from the university’s Agroecosystem Sustainability Center and the College of Agricultural, Consumer and Environmental Sciences used the sophisticated agroecosystem model ecosys to explain why corn yield is higher after soybean at normal nitrogen fertilization rates; how corn-soy rotation impacts soil greenhouse gas emissions and nitrogen leaching; and when corn-soy rotation is most economically advantageous.

“We found that while corn-soy rotation can boost corn yields and reduce nitrogen fertilizer needs, the benefits come with nuanced environmental and soil carbon trade-offs,” said study leader Kaiyu Guan, founding director of the ASC and ACES Levenick Professor in the Department of Natural Resources and Environmental Sciences at Illinois.