title: Reducing human nitrogen use for food production.
abstract: Reactive nitrogen (N) is created in order to sustain food production, but only a small fraction of this N ends up being consumed as food, the rest being lost to the environment. We calculated that the total N input (TN) of global food production was 171 Tg N yr(-1) in 2000. The production of animal products accounted for over 50% of the TN, against 17% for global calories production. Under current TN per unit of food production and assuming no change in agricultural practices and waste-to-food ratios, we estimate that an additional TN of 100 Tg N yr(-1) will be needed by 2030 for a baseline scenario that would meet hunger alleviation targets for over 9 billion people. Increased animal production will have the largest impact on increasing TN, which calls for new food production systems with better N-recycling, such as cooperation between crop and livestock producing farms. Increased N-use efficiency, healthier diet and decreased food waste could mitigate this increase and even reduce TN in 2030 by 8% relative to the 2000 level. Achieving a worldwide reduction of TN is a major challenge that requires sustained actions to improve nitrogen management practices and reduce nitrogen losses into the environment.
authors.affiliation: School of Environmental Science and Engineering, South University of Science and Technology of China, Shenzhen, 518055, China.
authors.forename: Junguo
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Nature Conservation, Beijing Forestry University, Qinghua East Road 35, Haidian District, 100083, Beijing, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Ma
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, F-91191, Gif sur Yvette, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciais
authors.affiliation: Department of Applied Economics, University of Minnesota, St. Paul, Minnesota, United States.
authors.forename: Stephen
authors.initials: S
authors.lastname: Polasky
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D004777:Environment; D005502:Food; D006801:Humans; D058751:Livestock / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry*
chemical_list: D009584:Nitrogen