Cover Crop Management in Semi‐Arid Regions: Effect on Soil and Cash Crop

Fallow-based cropping systems in semi-arid regions have been profitable and often less risky than recrop; however, their use is damaging to soil health and may limit long-run profitability. Cover crops can reduce summer fallow while possibly improving soil health. This article addresses cover crop management impacts on soil organic matter, soil water and N, and subsequent cash crop yields and grain protein concentration. Earn 1 CEU in Soil & Water Management by reading the article and taking the quiz at Fallow-based cropping systems in semi-arid regions have been profitable and often less risky than recrop; however, their use is damaging to soil health and may limit long-run profitability. Soil health goes beyond nutrient levels and is critical for agroecosystem sustainability (Moebius-Clune et al., 2016). Cover crops can reduce summer fallow while possibly improving soil health. Improvements in soil health as measured by soil health indicators are unproven in semi-arid regions where cover crop biomass is low and stored soil water use by cover crops can reduce subsequent crop yield and residue. It is also often assumed that diverse cover crops are better for soil health than single-species cover crops, yet this is unproven in the Northern Great Plains. Many cover crop benefits, such as stabilizing soil, increasing water-holding capacity, promoting microbial activity, and reducing erosion are a direct result of increasing both above- and belowground organic matter. Another important function of cover crops is increasing plant-available nitrogen (PAN, organic matter N that readily becomes plant available) and improving nitrogen (N) use efficiency. Producers can manipulate cover crop residue amount and quality by selection of cover crop species and termination timing. This article addresses cover crop management impacts on soil organic matter (SOM), soil water and N, and subsequent cash crop yields and grain protein concentration. The authors’ focus is on cover crops planted as summer fallow replacement or partial summer fallow replacement in the Northern Great Plains. Grazing of cover crops may change soil response, wheat yield and protein, and economics, but grazing is not included in this article.

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