brewbooks/flickr

Fertilizer is fouling the air in California: Study

Due to heavy fertilizer use, California's Central Valley is behind up to 41 percent of the state's emissions of nitrogen oxide—an air pollutant and climate-warming gas

A large proportion of California's nitrogen oxide—which can cause harmful ozone and a variety of health impacts—comes from heavy fertilizer use in the state's Central Valley, according to a new study.


University of California, Davis, researchers reported today that as much as 41 percent of smog-causing nitrogen oxide emissions are coming from the state's Central Valley region, which grows more than half of US vegetables, fruits and nuts.

"The effect of large soil NOx emissions on air quality and human health remain unclear, but the magnitude of the flux alone raises concern about its potential impact, particularly in rural California," the authors wrote in the study published today in Science Advances journal.

Nitrogen oxides, a "family of air-polluting compounds," according to the study, are also pumped into the air via burning fossil fuels and car exhaust.

The pollutants spur ground level ozone, have been linked to asthma, other breathing problems and heart disease, and are a potent greenhouse gas. One pound of nitrous oxide—a common component of nitrogen oxide—has 300 times more climate warming impact than a pound of carbon dioxide, according to the U.S. Environmental Protection Agency.

The scientists collected data from flights over the farming region and analyzed it along with computer models.

They estimated between 25 percent and 41 percent of the state nitrogen oxide emissions come from farm soils that received nitrogen-based fertilizers.


Credit: UC Davis

The fertilizers simulate soil microbes that can convert nitrogen, an essential plant nutrient, to nitrogen oxide.

About half of nitrogen-based fertilizers put on crops are actually absorbed by plants.

The study built upon 2012 research from the university that reported, since 1750, nitrous oxide levels have increased 20 percent, largely due to heavy fertilizer use over the past 50 years.

The authors didn't vilify fertilizers. "We need to increase the food we're making," said lead author Maya Almaraz, a postdoctoral fellow at UC Davis, in a statement. "We need to do it on the land we have. But we need to do it using improved techniques."

Almaraz and colleagues pointed to potential solutions, including slow-release fertilizers that reduce emissions, healthy soil efforts to bolster crops' uptake and retention of nutrients, and precision agriculture, which would mean more discriminate fertilizer application.

"It's critical that new policies focus on incentives to bring the latest nutrient management technologies to farms so that growers can produce food more efficiently, increasing their bottom line and improving rural health," said senior author Ben Houlton, a professor with the UC Davis Department of Land, Air and Water Resources, and director of the John Muir Institute of the Environment, in a statement.

Climate activists pan carbon capture plans

'There are still no projects operating anywhere in the world that have delivered on time, on budget, or in the quantities promised.'

More than 500 environmental and community groups – from the Nassau Hiking & Outdoor Club to Greenpeace USA – have called on United States and Canadian leaders to abandon efforts to capture carbon emissions from fossil fuels and work harder to curb fossil fuel use in the first place.

Keep reading... Show less

Get our Good News newsletter

Get the best positive, solutions-oriented stories we've seen on the intersection of our health and environment, FREE every Tuesday in your inbox. Subscribe here today. Keep the change tomorrow.

Coral reefs face disaster from climate change if we don’t curb greenhouse gas emissions, report says

To save this underwater ecosystem, researchers argue, we’ll need to reduce global warming, improve local conditions and invest in restoration.
www.nytimes.com

A lawyer known for fighting Chevron was found guilty of contempt of court by a federal judge

The ruling is the latest episode in a long legal battle over the alleged dumping of oil in the Amazon region of Ecuador from the 1960s to the 1990s by Texaco, which Chevron acquired in 2001.
www.nytimes.com

Wildfires ravage Italy's Sardinia region in 'a disaster without precedent'

A 25-mile swath of vegetation, farms and villages is hit by one of the largest wildfires in decades, devastating the Italian tourist destination.
www.nytimes.com

Floods, heat, then floods again: England is battered by wild weather

Thunderstorms in London flooded hospitals’ emergency rooms and submerged streets for the second time this month.
www.nytimes.com