title: Reactive nitrogen and the world: 200 years of change.
abstract: This paper examines the impact of food and energy production on the global N cycle by contrasting N flows in the late-19th century with those of the late-20th century. We have a good understanding of the amounts of reactive N created by humans, and the primary points of loss to the environment. However, we have a poor understanding of nitrogen's rate of accumulation in environmental reservoirs, which is problematic because of the cascading effects of accumulated N in the environment. The substantial regional variability in reactive nitrogen creation, its degree of distribution, and the likelihood of increased rates of reactive-N formation (especially in Asia) in the future creates a situation that calls for the development of a Total Reactive Nitrogen Approach that will optimize food and energy production and protect environmental systems.
authors.affiliation: Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22903, USA. jng@virginia.edu
authors.forename: James N
authors.initials: JN
authors.lastname: Galloway
authors.forename: Ellis B
authors.initials: EB
authors.lastname: Cowling
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D004787:Environmental Pollution / Q000032:analysis / Q000266:history; D005523:Food Supply; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D009584:Nitrogen / Q000009:adverse effects / Q000032:analysis / Q000378:metabolism*; D009751:Nutritional Requirements; D026361:Reactive Nitrogen Species / Q000009:adverse effects* / Q000032:analysis / Q000266:history*
chemical_list: D004785:Environmental Pollutants; D026361:Reactive Nitrogen Species; D009584:Nitrogen