Dairy manure and forage crops can combine to reduce the amount of commercial nitrogen fertilizer needed to grow corn, researchers at the University of Pennsylvania have reported. That will reduce greenhouse gas emissions.
They compared a corn-soybean rotation and a dairy forage rotation under three different management regimens. The forages include nitrogen-fixing clovers and alfalfa.
The results are important because although nitrous oxide accounts for only seven per cent of U.S. greenhouse gas emissions, it is significantly more potent than carbon dioxide or methane in global warming, said Heather Karsten, associate professor of crop production/ecology in the College of Agricultural Sciences.
Nitrous oxide is almost 300 times more powerful than carbon dioxide and remains in the atmosphere for more than 100 years, she said.