Contrasting soil management systems had limited effects on soil health and crop yields in a North Central US Mollisol

Management practices such as relay cropping, cover crops, and no-tillage may promote soil health in the North Central United States. However, soil health indicators in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems involving multiple management practices are not well documented. The objective of this study was to determine the sensitivity of soil health metrics and the Soil Management Assessment Framework (SMAF) to contrasting management systems with different tillage, crops, and fertilization in a North Central US Mollisol. Different management systems, including conservation tillage and nitrogen fertilization strategies, cover cropping, and camelina [Camelina sativa (L.) Crantz] relay intercropping, were compared to a conventional corn-soybean system. Different systems did not affect most soil health indicators compared to the conventional system. Aggregate stability was the only indicator to change due to management, where no-till with cover crops increased aggregate stability by 38% compared with camelina relay cropping. The SMAF scores for all the soil quality indices were unaffected by treatments but displayed high values of over 90%. Overall, crop yields were more closely related to weather conditions and management systems than to soil health indicators. Soybean yields were decreased (between 1 and 2 Mg ha-1) in the camelina relay cropping system, while corn yields were lower (up to 70%) in the treatment that received no N fertilization. Ultimately, these findings suggest that soil health indicators are resilient to change due to management in these highly productive Mollisols and may not be closely associated with crop yields. The sensitivity of soil health metrics and Soil Management Assessment Framework (SMAF) to management systems was studied in North Central United States. Management systems did not affect most soil health indicators compared to the conventional corn-soybean rotation. No-tillage with cover crops increased aggregate stability by 38% compared with camelina relay crop. SMAF scores were similar for all treatments and indicated soils were functioning at over 90% of their potential. Crop yields were more closely related to weather conditions and management systems than to soil health.