title: Exploring global changes in nitrogen and phosphorus cycles in agriculture induced by livestock production over the 1900-2050 period.
abstract: Crop-livestock production systems are the largest cause of human alteration of the global nitrogen (N) and phosphorus (P) cycles. Our comprehensive spatially explicit inventory of N and P budgets in livestock and crop production systems shows that in the beginning of the 20th century, nutrient budgets were either balanced or surpluses were small; between 1900 and 1950, global soil N surplus almost doubled to 36 trillion grams (Tg) · y(-1) and P surplus increased by a factor of 8 to 2 Tg · y(-1). Between 1950 and 2000, the global surplus increased to 138 Tg · y(-1) of N and 11 Tg · y(-1) of P. Most surplus N is an environmental loss; surplus P is lost by runoff or accumulates as residual soil P. The International Assessment of Agricultural Knowledge, Science, and Technology for Development scenario portrays a world with a further increasing global crop (+82% for 2000-2050) and livestock production (+115%); despite rapidly increasing recovery in crop (+35% N recovery and +6% P recovery) and livestock (+35% N and P recovery) production, global nutrient surpluses continue to increase (+23% N and +54% P), and in this period, surpluses also increase in Africa (+49% N and +236% P) and Latin America (+75% N and +120% P). Alternative management of livestock production systems shows that combinations of intensification, better integration of animal manure in crop production, and matching N and P supply to livestock requirements can effectively reduce nutrient flows. A shift in human diets, with poultry or pork replacing beef, can reduce nutrient flows in countries with intensive ruminant production.
authors.affiliation: PBL Netherlands Environmental Assessment Agency, 3720 AH, Bilthoven, The Netherlands.
authors.forename: Lex
authors.initials: L
authors.lastname: Bouwman
authors.forename: Kees Klein
authors.initials: KK
authors.lastname: Goldewijk
authors.forename: Klaas W
authors.initials: KW
authors.lastname: Van Der Hoek
authors.forename: Arthur H W
authors.initials: AH
authors.lastname: Beusen
authors.forename: Detlef P
authors.initials: DP
authors.lastname: Van Vuuren
authors.forename: Jaap
authors.initials: J
authors.lastname: Willems
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Rufino
authors.forename: Elke
authors.initials: E
authors.lastname: Stehfest
mesh_terms: D000383:Agriculture / Q000266:history* / Q000379:methods / Q000639:trends*; D000818:Animals; D057231:Climate Change; D049673:History, 20th Century; D049674:History, 21st Century; D058751:Livestock / Q000254:growth & development*; D008962:Models, Theoretical; D058458:Nitrogen Cycle / Q000502:physiology*; D010758:Phosphorus / Q000378:metabolism / Q000502:physiology*; D012987:Soil / Q000737:chemistry
chemical_list: D012987:Soil; D010758:Phosphorus