Wednesday, December 29, 2010
NoTill Cuts Greenhouse Gases
Did you ever have nitrous oxide for dental work? Or use it to increase horsepower of an engine?
It is a powerful gaseous mixture of the elements in our atmosphere, Nitrogen and Oxygen. Mixed together they are green house gas.
"Tony Vyn, a professor of agronomy, finds that no-till reduces nitrous oxide emissions by 57% over chisel tilling, which mixes crop residue into surface soil, and 40% over moldboard tilling, which completely inverts soil as well as the majority of surface residue.
"There was a dramatic reduction simply because of the no-till," says Vyn, whose findings were published in the Soil Science Society of America Journal. "We think the soil disturbance and residue placement impacts of chisel plowing and moldboard plowing modify the soil physical and microbial environments such that more nitrous oxide is created and released."
During early season nitrogen fertilizer applications on corn, no-till may actually reduce nitrous oxide emissions from other forms of nitrogen present in, or resulting from, that fertilizer.
Nitrous oxide is the third-most abundant greenhouse gas in the atmosphere but, according to the U.S. Environmental Protection Agency, has about 310 times more heat-trapping power than carbon dioxide in part because of its 120-year lifespan.
"This suggests there is another benefit to no-till beyond soil conservation and improving water quality," Vyn says. "There is an air quality benefit as well."
Using a corn-soybean rotation instead of continuous corn decreased nitrous oxide emissions by 20% in the three-year study. Vyn says the reduction could be even greater, though, because for the long-term experiment, both continuous corn and rotation crops were fertilized based on the needs of continuous corn. A rotation cornfield would normally receive 20% less nitrogen.
Finding ways to reduce nitrous oxide emissions is important because food production accounts for about 58% of all emissions of the gas in the United States. Of that, about 38% is coming from the soil.
"There is more nitrous oxide emission coming from agriculture than the tailpipes of cars and trucks," Vyn says. "And there is likely to be more nitrous oxide emission if we increase nitrogen application rates to increase cereal yields."
Science keeps bashing ethanol and notill for political reasons.
They both make sense to me.