title: Feeding the Corn Belt: Opportunities for phosphorus recycling in U.S. agriculture.
abstract: The supply of phosphorus (P) is a critical concern for food security. Concentrated mineral P deposits have been the source of almost all new P entering the biosphere. However, this resource is often used inefficiently, raising concerns about both nutrient pollution and future access to fertilizers. One solution to both of these problems is to enhance our ability to capture and recycle P from waste streams. However, the efficacy of doing this has not been rigorously explored. Here, we examine the potential for recycling major P sources in the United States to supply the necessary P for domestic corn (maize) production. Using 2002 population and agricultural census data, we examine the distribution of three key recyclable P sources (human food waste, human excreta, and animal manure) and P demand from grain and silage corn across the country to determine the distance P would need to be transported from sources to replenish P removed from soils in harvested corn plants. We find that domestic recyclable P sources, predominantly from animal manures, could meet national corn production P demands with no additional fertilizer inputs. In fact, only 37% of U.S. sources of recyclable P would be required to meet all P demand from U.S. corn harvested annually. Seventy-four percent of corn P demand could be met by recyclable P sources in the same county. Surplus recyclable P sources within-counties would then need to travel on average 302 km to meet the largest demand in and around the center of the 'Corn Belt' region where ~50% of national corn P demand is located. We find that distances between recyclable sources and crop demands are surprisingly short for most of the country, and that this recycling potential is mostly related to manure. This information can help direct where recycling efforts should be most-effectively directed.
authors.affiliation: Department of Natural Resource Sciences, McGill University, 21,111 Lakeshore Road, Sainte Anne de Bellevue, QC, Canada. Electronic address: genemetson@gmail.com.
authors.forename: Geneviève S
authors.initials: GS
authors.lastname: Metson
authors.affiliation: University of Minnesota, Institute on the Environment, 1954 Buford Avenue, St. Paul, MN 55108, USA.
authors.forename: Graham K
authors.initials: GK
authors.lastname: MacDonald
authors.affiliation: Department of Natural Resource Sciences, McGill University, 21,111 Lakeshore Road, Sainte Anne de Bellevue, QC, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Haberman
authors.affiliation: Bordeaux Sciences Agro, Univ. Bordeaux, UMR 1391 ISPA, 33175 Gradignan Cedex, France; INRA, UMR 1391 ISPA, 33882 Villenave d'Ornon Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nesme
authors.affiliation: Department of Natural Resource Sciences, McGill University, 21,111 Lakeshore Road, Sainte Anne de Bellevue, QC, Canada; McGill School of Environment, McGill University, 3534 University Street, Montreal, QC, Canada.
authors.forename: Elena M
authors.initials: EM
authors.lastname: Bennett
keywords: Agriculture; Corn; Phosphorus; Recycling; Sustainability