Solutions for a nitrogen-soaked world

Jan 17, 2012

Nitrogen is both an essential nutrient and a pollutant, a byproduct of fossil fuel combustion and a fertilizer that feeds billions, a benefit and a hazard, depending on form, location, and quantity. Agriculture, industry and transportation have spread nitrogen liberally around the planet, say sixteen scientists in the latest edition of ESA's Issues in Ecology series, "Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions," with complex and interrelated consequences for ecological communities and our dependence upon the resources they provide, as well as human health.

Pulling from a broad pool of expertise in air quality, agronomy, ecology, epidemiology and groundwater geochemistry, the sixteen authors track nitrogen through its different chemical forms and biological incarnations as it progresses across economic, environmental and regulatory bounds. They argue for a systematic, rather than piecemeal, approach to managing the resource and its consequences. "We're really trying to identify solutions," said lead author Eric Davidson, a soil ecologist and executive director of the Woods Hole Research Center. "This is a paper about how much we do know, not about what we don't know. We know about nitrogen cycles, and sources, and we know problems can be addressed in economically viable ways."

Once a critical limiting element of , excess nitrogen now overflows from fields and stockyards, typically in the forms of ammonia and nitrate, contaminating drinking water and air, and altering the chemistry and constituency of . "Nitrogen is readily mobile, and very efficiently distributed through wind and water," said author James Galloway, a biogeochemist at the University of Virginia. Airborne nitrogen from , manure piles, automobile tailpipes, and smokestacks travels with the wind to settle over distant forests and .

Though extra fertilizer sounds like a good thing, it does not benefit all species equally, leading, in more extreme cases, to sudden changes like algal blooms, which smother competing species and can create health hazards. Nitrogen also acidifies soil, leaching away other important nutrients. Interventions to control nitrogen oxide emissions from power plants and gasoline-fueled engines have made encouraging progress. Mitigating agricultural sources of is more complicated.

"We know how to reduce nitrogen oxides from to a very small amount. We know the science, we have the engineering, and we have the regulatory tools," said Galloway, setting emissions aside as a political, rather than a scientific, hurdle. "On the food side, that's where it gets interesting," he said. "How can you still produce the food the society demands, needs, yet use less nitrogen to produce it?"

The report tabulates strategies to help farmers maximize efficient use of fertilizer, rather than just maximize crop yield, including buffer strips and wetlands, manure management, and ideal patterns of fertilizer application. It also considers the cost of implementing them, and programs for buffering farmers against losses in bad years.

"There are a variety of impacts due to the human use of nitrogen," said Galloway. "The biggest is a positive one, in that it allows us to grow food for Americans and people in other countries, and we don't want to lose sight of that." Balancing inexpensive abundant food against the damage done by escaping into the environment is a conversation the authors would like to hear more prominently in policy arenas.

"Yes, we have to feed people, but we also need clean drinking water, clean air, and fisheries in the Gulf of Mexico," said Davidson. "The science helps to show those tradeoffs, and where we most stand to gain from improved nutrient management in agriculture."

Explore further: Stopping the leaks

More information: The report is published by Ecological Society of America's Issues in Ecology, and can be viewed in Issue 15 at www.esa.org/science_resources/issues_ecology.php

Provided by Ecological Society of America

4 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Put more nitrogen into milk, not manure

May 28, 2010

The more efficient dairy farmers are in managing nitrogen, the more milk their cows will produce and the less nitrogen will be wasted in manure and urine, according a study by Agricultural Research Service (ARS) scientists ...

Improve crop yield by removing manure solids

Mar 29, 2011

Manure has long been used as a crop fertilizer, but the challenge of finding an efficient use of the nutrients found in manure is ever present. The ratio of nitrogen to phosphorus in manure is low in relation to the nutrient ...

Is nitrogen the new carbon?

Sep 21, 2009

In looking forward to the next Green Revolution, researchers have been carefully examining the role of nitrogen fixation in delivering successful crops around the globe.

Improving swine waste fertilizer

Jul 08, 2008

Swine production generates large amounts of waste. While this waste contains nutrients that may serve as fertilizer when applied to agricultural fields, the ratio of nutrients in the waste is different than what a crop requires.

How much nitrogen is too much for corn?

Apr 23, 2007

North Carolina State researchers recently discovered a test that quickly predicts nitrogen levels in the humid soil conditions of the southeastern United States. These scientists report that the Illinois Soil Nitrogen Test ...

Recommended for you

Stopping the leaks

15 minutes ago

When a big old cast-iron water main blows, it certainly makes for a spectacular media event.

Alpine lifelines on the brink

1 hour ago

Only one in ten Alpine rivers are healthy enough to maintain water supply and to cope with climate impacts according to a report by WWF. The publication is the first-ever comprehensive study on the condition ...

Research that holds water

2 hours ago

Water is a vulnerable resource coming under increasing pressure in many parts of the world. The Research Council of Norway is providing funding to a number of research projects seeking to solve challenges related to the supply ...

User comments : 0