Fact Sheets & Studies

Reactive nitrogen and human-induced changes to the global nitrogen cycle,
plus farm-based solutions to nitrogen pollution.

Fact Sheets

Nitrous oxide (N2O) is an atmospheric gas commonly known as laughing gas. Though less abundant than carbon dioxide in the atmosphere, it is 300 times more powerful than carbon dioxide in trapping heat. It also lingers in the atmosphere longer than CO2. In addition to its heat-trapping properties, Scientists recently declared N2O the world's greatest source of atmospheric ozone.Nitrous Oxide

Nitrous oxide (N2O) is an atmospheric gas commonly known as laughing gas. Though less abundant than carbon dioxide in the atmosphere, it is 300 times more powerful than carbon dioxide in trapping heat. It also lingers in the atmosphere longer than CO2. In addition to its heat-trapping properties, Scientists recently declared N2O the world’s greatest source of atmospheric ozone.

Nitrogen is literally all around us, including nearly 80 percent of each breath we take. Though it is the most plentiful element in the earth's atmosphere, it's unusable in its inert state and must be transformed into reactive nitrogen before plants and animals can use it to make protein, DNA, and other compounds essential for life. Yet changes to the nitrogen cycle, like the more well-known changes to the carbon cycle, are creating environmental havoc.Reactive Nitrogen

Nitrogen is literally all around us, including nearly 80 percent of each breath we take. Though it is the most plentiful element in the earth’s atmosphere, it’s unusable in its inert state and must be transformed into reactive nitrogen before plants and animals can use it to make protein, DNA, and other compounds essential for life. Yet changes to the nitrogen cycle, like the more well-known changes to the carbon cycle, are creating environmental havoc.

Farmers across the country are employing cutting edge technology to reduce their environmental impact without sacrificing crop yields.Farm-Level Solutions

Farmers across the country are employing cutting edge technology to reduce their environmental impact without sacrificing crop yields.

Studies and Reports

Biofuels
October 4, 2011
National Academy of Sciences, Lester B. Lave
Renewable Fuel Standard: Potential Economic and Environmental Effects of U.S. Biofuel Policy
This committee report on the Renewable Fuel Standard (RFS), which mandates that 35 billion gallons of ethanol-equivalent biofuels and 1 billion gallons of biomass-based diesel be consumed in the United States by 2022, explores the barriers to reducing global greenhouse gas emissions through the RFS.
July 15, 2010
Center for Agricultural and Rural Development Iowa State, Bruce A. Babcock
Costs and Benefits to Taxpayers, Consumers, and Producers from U.S. Ethanol Policies
This study examines the likely consequences on the U.S. ethanol industry, corn producers, taxpayers, fuel blenders, and fuel consumers if current policy is not extended.
March 15, 2010
BioScience, Thomas Hertel
Effects of US Maize Ethanol on Global Land Use and Greenhouse Gas Emissions: Estimating Market Mediated Response
Purdue’s Thomas Hertel concludes that U.S.-grown corn for fuel triggers commodity price changes that ultimately lead to native ecosystems being destroyed, with a high carbon price tag. Hertel’s study finds emissions from indirect land-use change make corn ethanol higher in greenhouse gas emissions than gasoline.
February 10, 2010
Proceedings of the National Academy of Sciences USA, David M. Lapola
Indirect Land-use Changes Can Overcome Carbon Savings from Biofuels in Brazil
This study forecasts that land-use conversions from rainforest to rangeland to biofuel plantations in Brazi lwill continue increasing as demand for ethanol stays high.
July 17, 2009
Science, David Tilman
Beneficial Biofuels - The Food, Energy, and Environment Trilemma
A look at the pros and cons of biofuels development. There is much to be gained from biofuels done right, and much to lose when they are done wrong.
January 15, 2009
UNESCO-SCOPE, Robert Howarth
Scope biofuels impact on the environment report
How biofuels development affects the environment. While many countries and companies are motivated to invest in biofuels because of their potential to reduce greenhouse gas emissions, thus far the data suggests that first generation biofuels like ethanol have failed to live up to that promise.
February 15, 2008
Science Express, Tim Searchinger
Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land Use Change
The increase in U.S. corn and soybean production for biofuels is causing a net increase in greenhouse gas emissions, when you factor in indirect land use change.
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Nitrogen Imbalance and Agriculture
January 17, 2012
Issues in Ecology #15, Ecological Society of America, Eric Davidson
Excess Nitrogen in the U.S Environment: Trends, Risks, and Solutions
The nitrogen cycle has been profoundly altered by human activities, and that in turn is affecting human health, air and waterquality, and biodiversity in the U.S. In this report, a multidisciplinary team of scientists reviews US nitrogen pollution trends, risks, and solutions.
October 1, 2011
Nature, Jonathan A. Foley
Solutions for a cultivated planet
We can feed the world if we get smart about production, eat less meat, stop waste.
November 6, 2009
Science, James J. Elser
Shifts in Lake N:P Stoichiometry and Nutrient Limitation Driven by Atmospheric Nitrogen Deposition
Atmospheric nitrogen deposition increased the stoichiometric ratio of nitrogen and phosphorus in lakes in Norway, Sweden, and Colorado, United States, and as a result, patterns of ecological nutrient limitation were shifted, leading to algae blooms in the lakes that disturbed the food chain.
September 11, 2009
ournal of Environmental Quality, R. L. Mulvaney
Synthetic Nitrogen Fertilizers Deplete Soil Nitrogen: A Global Dilemma for Sustainable Cereal Production
A University of Illinois study on the impact of nitrogen fertilizer application on soil productivity over time. The study finds that heavy nitrogen fertilizer use decreases soil health and productivity.
June 19, 2009
Science, Peter Vitousek
Nutrient Imbalances in agricultural Development
The increase in U.S. corn and soybean production for biofuels is causing a net increase in greenhouse gas emissions, when you factor in indirect land use change.
May 16, 2008
Science, James N. Galloway
Transformation of the Nitrogen Cycle: Recent Trends, Questions, and Potential Solutions
Descrition of the human influence on the global nitrogen cycle, including an examination of the nitrogen divide: excessive nitrogen use and pollution in some regions, and nitrogen deficiencies which cause food shortages in others.
May 1, 2007
Woods Hole Research Center, Elizabeth Braun
UNEP Report: Reactive Nitrogen in the Environment UNEP
UN Environment Programme (UNEP) study on the nitrogen divide: nitrogen is a valuable resource that allows us to feed the world, but it needs to be managed better. Some places don't have enough and face famine. Some places overuse nitrogen fertilizer, resulting in environmental and health problems.
April 15, 2007
UNESCO-SCOPE, James N. Galloway
Human alteration of the nitrogen cycle: Threats, benefits and opportunities
A useful, visual summary of human activities that have altered the world's nitrogen supply.
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Public Health Impacts of Nitrogen Pollution
September 23, 2009
Nature, Johan Rockström
A safe operating space for humanity
Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockström and colleagues.
February 15, 2008
Island Express, Robert Howarth, Kilaparti Ramakrishna
Nutrient Management
An examination of the health and environmental consequences of nitrogen fertilizer pollution. This is a chapter from a larger publication on human health and the environment.
January 1, 2003
Frontiers in Ecology & Environment, Alan Townsend
Human health effects of a changing global nitrogen cycle
Examples of how increasing production and use of fixed nitrogen poses a public health risk.
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Coastal "Dead Zones"
September 6, 2008
Elsevier, Robert Howarth
Coastal nitrogen pollution: A review of sources and trends globally and regionally
A study on coastal dead zones and their causes
March 1, 2008
World Resources Institute, Mindy Selman
Eutrophication and Hypoxia in Coastal Areas: A Global Assessment of the State of Knowledge
A broad, global summary of eutrophication and hypoxia (dead zones) in coastal waters, and the long-term implications of continued ocean contamination from farm fertilizer runoff.
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Nitrogen Chemical
Cheat Sheet

Nitric Oxide (NO) & Nitrogen Dioxide (NO2)

These gases lead to ground-level ozone. Collectively referred to as NOx (pronounced ENN-Oh-Ex), they come mostly from fossil fuel burning, except in the tropics, where some NOx is produced by soils.

NH3 Ammonia, or Anhydrous Ammonia gas

Derived from nitrogen applied to the land through chemical fertilizer, manure and other animal wastes. Some NH3 is produced from older cars that lack catalytic converters. NH3 contributes to smog and haze; fine particles cause respiratory problems.

N2O Nitrous Oxide

A greenhouse gas, as well as a gas that contributes to destruction of ozone in the stratosphere. N2O comes from bacterial processing of nitrogen in the environment, whether it originates as NO, NO2, NH3 or some other form.

Nitrogen

Atmospheric, “unfixed” nitrogen. Not usable by plants or animals. About 80 percent of the atmosphere is comprised of N2.

Fixed Nitrogen

Nitrogen that has been chemically altered to make it usable by plants. Fixed nitrogen is a primary component in agricultural fertilizer.

Nitrates

Forms when nitrogen from ammonia or other sources—commonly fertilizers—mixes with oxygenated water. Nitrate-polluted drinking water can cause health problems including “blue baby syndrome” caused by a lack of oxygen in the blood.

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