Nitrous oxide emissions, coming from legume cover crops, manure, can be reduced

by Jeff Mulhollem, Penn State University
August 2, 2021

UNIVERSITY PARK, Pa. — The application of manure after the growth and demise of legume cover crops in rotations is a recipe to increase nitrous oxide releases during ensuing corn growth, according to a team of Penn State researchers who conducted a new study. They suggest that innovative management strategies are needed to reduce these emissions. 

The greenhouse gas — nitrous oxide — is important because it is about 300 times better at trapping heat than is carbon dioxide, so even small emissions of nitrous oxide affect the climate, explained team leader Armen Kemanian, professor of production systems and modeling in the College of Agricultural Sciences.

“In the United States, agriculture accounts for approximately 10% of all greenhouse gas emissions but contributes about 80% of all nitrous oxide emissions linked to human activity,” he said. “Of the three major greenhouse gases emitted naturally — carbon dioxide, methane and nitrous oxide — nitrous oxide is the most important in field crops. We have an obligation, I believe, to develop climate-friendly farming practices and reduce nitrous oxide emissions.”

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