More than a century ago, two German chemists discovered how to convert the nitrogen in Earth’s atmosphere to ammonia, which could be used in a variety of products, including fertilizers to increase crop yield. Their work was of little consequence until the 1960s, when mounting global famine sparked the Green Revolution.
Today, it is estimated that the increased crop yield achieved by fertilizer sustains one-third of the Earth’s population. Nearly 100 million tons is applied worldwide, with the U.S. and China among the most fertilized lands. In the U.S., corn is one of the most heavily fertilized crops, with typical applications of 150 lbs per acre each year.
When fertilizer is applied, a small amount of the nitrogen added to the soil escapes to the atmosphere as ammonia and nitrogen gas. Farm animals also emit ammonia to the atmosphere through excrement, with high concentrations in feedlots and barns.
These nitrogen and ammonia emissions can be carried hundreds of miles downwind. Along the way, they are converted to particles that are easy to breathe and hazardous to human health. And when they are eventually deposited onto the landscape, they can lead to harmful algal blooms in waterways.
“The exonomous and agricultural scientists are trying to develop a fertilizer that will work on the principle of a controlled release of ammonia or nitrogen from the fertilizer,” says Viney Aneja, a researcher at North Carolina State University. “That is a very important development that is currently taking place.”
Now, more than ever, we need efficiency standards to safeguard the environment from ammonia pollution and other unintended consequences of fertilizer dependence.
Photo, taken taken on February 10, 2010, courtesy of IRRI Images via Flickr.