@article {Sutton2011a,
	title = {{Too much of a good thing.}},
	journal = {Nature},
	volume = {472},
	number = {7342},
	year = {2011},
	month = {apr},
	pages = {159{\textendash}61},
	keywords = {agriculture, Agriculture: economics, Animals, Biodiversity, Climate Change, Cost-Benefit Analysis, Diet, Environmental Pollution, Environmental Pollution: adverse effects, Environmental Pollution: analysis, Environmental Pollution: economics, Environmental Pollution: statistics {\&} numerical da, Fertilizers, Fertilizers: analysis, Food Supply, Fossil Fuels, Humans, International Cooperation, Meat, Meat: utilization, nitrogen, Nitrogen Fixation, Nitrogen: adverse effects, Nitrogen: analysis, Nitrogen: economics, Nitrogen: metabolism, Reactive Nitrogen Species, Reactive Nitrogen Species: adverse effects, Reactive Nitrogen Species: analysis, Reactive Nitrogen Species: chemistry, Reactive Nitrogen Species: metabolism},
	issn = {1476-4687},
	doi = {10.1038/472159a},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21478874},
	author = {Sutton, Mark A. and Oenema, Oene and Erisman, Jan Willem and Leip, Adrian and van Grinsven, Hans and Winiwarter, Wilfried}
}
@article {Hutton2017,
	title = {{Toward a nitrogen footprint calculator for Tanzania}},
	journal = {Environmental Research Letters},
	volume = {12},
	number = {3},
	year = {2017},
	abstract = {{\textcopyright} 2017 IOP Publishing Ltd.We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there is not enough soil nitrogen to produce adequate food, excess nitrogen that escapes into the environment causes a cascade of ecological and human health problems. To identify, quantify, and contribute to solving these problems, this paper presents a nitrogen footprint tool for Tanzania. This nitrogen footprint tool is a concept originally designed for the United States of America (USA) and other developed countries. It uses personal resource consumption data to calculate a per-capita nitrogen footprint. The Tanzania N footprint tool is a version adapted to reflect the low-input, integrated agricultural system of Tanzania. This is reflected by calculating two sets of virtual N factors to describe N losses during food production: one for fertilized farms and one for unfertilized farms. Soil mining factors are also calculated for the first time to address the amount of N removed from the soil to produce food. The average per-capita nitrogen footprint of Tanzania is 10 kg N yr-1. 88{\%} of this footprint is due to food consumption and production, while only 12{\%} of the footprint is due to energy use. Although 91{\%} of farms in Tanzania are unfertilized, the large contribution of fertilized farms to N losses causes unfertilized farms to make up just 83{\%} of the food production N footprint. In a developing country like Tanzania, the main audiences for the N footprint tool are community leaders, planners, and developers who can impact decision-making and use the calculator to plan positive changes for nitrogen sustainability in the developing world.},
	keywords = {nitrogen, nitrogen footprint, Sub-Saharan Africa, Tanzania},
	issn = {17489326},
	doi = {10.1088/1748-9326/aa5c42},
	author = {Hutton, M.O. and Leach, Allison M. and Leip, Adrian and Galloway, James N. and Bekunda, M. and Sullivan, C. and Lesschen, J.P.}
}
