title: Surface N balances and reactive N loss to the environment from global intensive agricultural production systems for the period 1970-2030.
abstract: Abstract Data for the historical years 1970 and 1995 and the FAO-Agriculture Towards 2030 projection are used to calculate N inputs (N fertilizer, animal manure, biological N fixation and atmospheric deposition) and the N export from the field in harvested crops and grass and grass consumption by grazing animals. In most industrialized countries we see a gradual increase of the overall N recovery of the intensive agricultural production systems over the whole 1970-2030 period. In contrast, low N input systems in many developing countries sustained low crop yields for many years but at the cost of soil fertility by depleting soil nutrient pools. In most developing countries the N recovery will increase in the coming decades by increasing efficiencies of N use in both crop and livestock production systems. The surface balance surplus of N is lost from the agricultural system via different pathways, including NH3 volatilization, denitrification, N20 and NO emissions, and nitrate leaching from the root zone. Global NH3-N emissions from fertilizer and animal manure application and stored manure increased from 18 to 34 Tg x yr(-1) between 1970 and 1995, and will further increase to 44 Tg x yr(-1) in 2030. Similar developments are seen for N2O-N (2.0 Tg x yr(-1) in 1970, 2.7 Tg x yr(-1) in 1995 and 3.5 Tg x yr(-1) in 2030) and NO-N emissions (1.1 Tg x yr(-1) in 1970, 1.5 Tg x yr(-1) in 1995 and 2.0 Tg x yr(-1) in 2030).
authors.affiliation: Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilt- hoven, The Netherlands. Lex.Bouwman@rivm.nl
authors.forename: A F
authors.initials: AF
authors.lastname: Bouwman
authors.forename: G
authors.initials: G
authors.lastname: Van Drecht
authors.forename: K W
authors.initials: KW
authors.lastname: van der Hoek
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D000829:Animals, Domestic; D018556:Crops, Agricultural; D004777:Environment; D006801:Humans; D008962:Models, Theoretical; D009584:Nitrogen; D026361:Reactive Nitrogen Species
chemical_list: D026361:Reactive Nitrogen Species; D009584:Nitrogen