Conservation practices induce tradeoffs in soil function: Observations from the northern Great Plains

Authors: Liebig, Mark; Acosta-Martinez, Veronica; Archer, David; Halvorson, Jonathan; Hendrickson, John; Kronberg, Scott; SAMSON-LIEBIG, SUSAN - Natural Resources Conservation Service (NRCS, USDA); VETTER, JENNIFER - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2022
Publication Date: 3/22/2022
Citation: Liebig, M.A., Acosta Martinez, V., Archer, D.W., Halvorson, J.J., Hendrickson, J.R., Kronberg, S.L., Samson-Liebig, S.E., Vetter, J.M. 2022. Conservation practices induce tradeoffs in soil function: Observations from the northern Great Plains. Soil Science Society of America Journal. https://doi.org/10.1002/saj2.20375.
DOI: https://doi.org/10.1002/saj2.20375

Interpretive Summary: Dryland cropping occupies nearly 200,000 square miles within the northern Great Plains. Over the past 30 years, the region has experienced significant grassland conversion to cropland coupled with a transition away from small-grain cropping systems toward systems increasingly dominated by corn and soybean. Cropland expansion and reduced crop rotation diversity in the region has negatively impacted soil health, creating a need to identify conservation practices that can counteract this trend. A three-year study was conducted to quantify soil health responses to crop diversity/intensity, cover crops, and livestock integration under controlled experimental conditions, and land use (dryland cropping, native grassland, untilled pasture) on working farms and ranches, all on a common soil type in southcentral North Dakota, USA. Among dryland cropping practices, diverse, continuous cropping led to improvements in soil structure, nutrient supply potential, and biological habitat, but increased soil acidification and soil nitrate accumulation. Cover crops had a negligible effect on the soil, while livestock integration on cropland improved nutrient supply potential and biological habitat, but impaired infiltration. Relative to dryland cropping, soil health was consistently improved under perennial systems. Outcomes from this study suggest retention of perennial agroecosystems and adoption of diverse, nutrient-efficient dryland cropping practices should be prioritized to enhance soil health in the northern Great Plains.

Technical Abstract: Over the past 30 years, agricultural land use in the northern Great Plains has negatively impacted soil health and associated ecosystem services through grassland conversion to cropland and a transition away from small-grain cropping systems to warm-season crops. Mitigating these impacts requires adoption of conservation practices, but information about how conservation practices influence on soil condition and function are needed. This study sought to quantify near-surface soil responses to crop diversity/intensity, cover crops, and livestock integration under controlled experimental conditions, and land use (dryland cropping vs. perennial agroecosystems) on working farms and ranches, all on a common Haplustoll soil in southcentral North Dakota, USA. Among dryland cropping practices, diverse, continuous cropping led to improvements in soil structure, nutrient supply potential, and biological habitat, but increased soil acidification and soil nitrate accumulation. Cover crops had a negligible effect on soil condition and function, while livestock integration on cropland improved nutrient supply potential and biological habitat, but impaired water intake into soil. Relative to dryland cropping, soil conditions and functions were consistently improved under perennial agroecosystems. Retention of perennial agroecosystems and adoption of diverse, nutrient-efficient dryland cropping practices should be prioritized to enhance soil health in the northern Great Plains.