Comprehensive impacts of diversified cropping on soil health and sustainability

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Baldwin-Kordick, Rebecca
De, Mriganka
Lopez, Miriam
Liebman, Matt
Lauter, Nick
Marino, John
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McDaniel, Marshall
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.

The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.

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  • Department of Farm Crops and Soils (1917–1935)

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Iowa Nutrient Research Center
The Iowa Nutrient Research Center was established to pursue science-based approaches to evaluating the performance of current and emerging nutrient management practices and providing recommendations on practice implementation and development. Publications in this digital repository are products of INRC-funded research. The INRC is headquartered at Iowa State University and operates in collaboration with the University of Iowa and the University of Northern Iowa. Additional project information is available at:
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AgronomyIowa Nutrient Research Center
Conventional agriculture in the Midwest US lacks diversity, relies heavily on external inputs to maintain crop yields, and contributes to soil and water quality degradation. Using diverse crop rotations and incorporating livestock are promising solutions to these and other problems linked to current cropping systems dominated by maize (Zea mays L.) and soybean (Glycine max (L.) Merr.). To better understand how agricultural diversification comprehensively affects soil health and function, we compared 20 soil health parameters linked to critical soil ecosystem services in 1) a conventional 2-year maize-soybean rotation, and 2) a diverse 4-year maize-soybean-oat (Avena sativa L.)+alfalfa (Medicago sativa L.)-alfalfa rotation that periodically received cattle manure. The strongest and most salient improvements in soil health from the diversified, 4-year cropping system included: 8% reduction in soil resistance to root growth (p = .006), 16% increase in cation exchange capacity (p = .001), 157% increase in salt-extractable soil carbon (p = .024), and 62% increase in soil microbial biomass (p = .017). These comprehensive improvements in general soil functioning coincided with enhanced crop yields, reduced requirement for agricultural inputs, and decreased environmental impacts – all while maintaining profitability. Despite declines in cropping system diversity globally, but especially in the Midwest US, these results provide strong evidence for the benefits of diversification.
This article is published as Baldwin-Kordick, Rebecca, Mriganka De, Miriam D. Lopez, Matt Liebman, Nick Lauter, John Marino, and Marshall D. McDaniel. "Comprehensive impacts of diversified cropping on soil health and sustainability." Agroecology and Sustainable Food Systems (2022). doi:10.1080/21683565.2021.2019167. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.