Rotating corn and soybeans, a widely used practice among Midwest farmers, potentially could contribute to long-term declines in soil organic matter, according to new research from an Iowa State University scientist.
Steven Hall, an assistant professor of ecology, evolution and organismal biology, led the study, published recently in the academic journal Plant and Soil. The study examines the mechanisms that drive the decomposition of organic matter in soils that undergo long-term corn and soybean rotations. Hall said the study shows how corn and soybean rotations can provide important environmental and management benefits for farmers, but the practice also comes with tradeoffs that some farmers may wish to address by adjusting their management practices.
“It could be that the benefits of corn and soybean rotation may also come with some long-term costs,” he said.
Rotating corn and soybeans allows farmers to use less nitrogen fertilizer when growing corn. That benefits the environment and allows farmers to save on input costs. However, studies have noted corn-soybean crop rotation leads to lower organic matter in the soil when compared to land that undergoes continuous corn production, or when other crops are included in rotation along with corn and soybeans.
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Photo: Corn and soybean grow alongside one another in a field. Corn and soybean crop rotation provides benefits for farmers but also could reduce soil organic matter, according to new research from ISU scientists. Photo courtesy of Steven Hall.