Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico: Agricultural Strategies for Remediating Hypoxia |
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| Authors: | Eileen McLellan Dale Robertson Keith Schilling Mark Tomer Jill Kostel Doug Smith Kevin King |
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| Affiliation: | 1. Environmental Defense Fund, Washington, D.C.;2. Wisconsin Water Science Center, U.S. Geological Survey, Middleton, Wisconsin;3. IIHR‐Hydroscience and Engineering, University of Iowa, Iowa City, Iowa;4. National Laboratory for Agriculture and the Environment, USDA‐ARS, Ames, Iowa;5. The Wetlands Initiative, Chicago, Illinois;6. National Soil Erosion Research Laboratory, USDA‐ARS, West Lafayette, Indiana;7. Soil Drainage Research Unit, USDA‐ARS, Columbus, Ohio |
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| Abstract: | SPAtially Referenced Regression on Watershed models developed for the Upper Midwest were used to help evaluate the nitrogen‐load reductions likely to be achieved by a variety of agricultural conservation practices in the Upper Mississippi‐Ohio River Basin (UMORB) and to compare these reductions to the 45% nitrogen‐load reduction proposed to remediate hypoxia in the Gulf of Mexico (GoM). Our results indicate that nitrogen‐management practices (improved fertilizer management and cover crops) fall short of achieving this goal, even if adopted on all cropland in the region. The goal of a 45% decrease in loads to the GoM can only be achieved through the coupling of nitrogen‐management practices with innovative nitrogen‐removal practices such as tile‐drainage treatment wetlands, drainage–ditch enhancements, stream‐channel restoration, and floodplain reconnection. Combining nitrogen‐management practices with nitrogen‐removal practices can dramatically reduce nutrient export from agricultural landscapes while minimizing impacts to agricultural production. With this approach, it may be possible to meet the 45% nutrient reduction goal while converting less than 1% of cropland in the UMORB to nitrogen‐removal practices. Conservationists, policy makers, and agricultural producers seeking a workable strategy to reduce nitrogen export from the Corn Belt will need to consider a combination of nitrogen‐management practices at the field scale and diverse nitrogen‐removal practices at the landscape scale. |
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| Keywords: | watershed management nutrients best management practices (BMPs) non‐point source pollution eutrophication rivers/streams wetlands |
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