Grassland-to-cropland conversion increased soil, nutrient, and carbon losses in the US Midwest between 2008 and 2016
[1];
[2];
[3];
[4];
[4]
- Univ. of Maryland, College Park, MD (United States)
- Univ. of Wisconsin, Madison, WI (United States); Great Lakes Bioenergy Research Center (GLBRC), Madison, WI (United States)
- US Environmental Protection Agency (EPA), Washington, DC (United States)
- US Environmental Protection Agency (EPA), Research Triangle Park, NC (United States)
After decades of declining cropland area, the United States (US) experienced a reversal in land use/land cover change in recent years, with substantial grassland conversion to cropland in the US Midwest. Although previous studies estimated soil carbon (C) loss due to cropland expansion, other important environmental indicators, such as soil erosion and nutrient loss, remain largely unquantified. In this study, we simulated the environmental impacts from the conversion of grassland to corn and soybeans for 12 US Midwestern states using the EPIC (Environmental Policy Integrated Climate) model. Between 2008 and 2016, over 2 Mha of grassland were converted to crop production in these states, with much less cropland concomitantly abandoned or retired from production. The net grassland-cropland conversion increased annual soil erosion by 7.9%, nitrogen (N) loss by 3.7%, and soil organic carbon loss by 5.6% relative to that of existing cropland, despite an associated increase in cropland area of only 2.5%. Notably, the above estimates represent the scenario of converting unmanaged grassland to tilled corn and soybeans, and impacts varied depending upon crop type and tillage regime. Corn and soybeans are dominant biofuel feedstocks, yet the grassland conversion and subsequent environmental impacts simulated in this study are likely not attributable solely to biofuel-driven land use change since other factors also contribute to corn and soybean prices and land use decisions. Nevertheless, our results suggest grassland conversion in the Upper Midwest has resulted in substantial degradation of soil quality, with implications for air and water quality as well. Additional conservation measures are likely necessary to counterbalance the impacts, particularly in areas with high rates of grassland conversion (e.g. the Dakotas, southern Iowa).
- Research Organization:
- Great Lakes Bioenergy Research Center (GLBRC), Madison, WI (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0018409; NNH13ZDA001N; NNX17AE66G; 18-CMS18-0052; 1639327
- OSTI ID:
- 1804757
- Journal Information:
- Environmental Research Letters, Vol. 16, Issue 5; ISSN 1748-9326
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Identifying representative crop rotation patterns and grassland loss in the US Western Corn Belt
National Geo-Database for Biofuel Simulations and Regional Analysis