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United States Department of Agriculture

Agricultural Research Service

Research Project: INCREASING SUSTAINABILITY AND MITIGATING GREENHOUSE GAS EMISSIONS OF FOOD AND BIOFUEL PRODUCTION SYSTEMS OF THE UPPER MIDWEST U.S.

Location: Soil and Water Management Research

Title: Challenges and opportunities for mitigating nitrous oxide emissions from fertilized cropping systems

Authors
item Venterea, Rodney
item Halvorson, Ardell
item Kitchen, Newell
item Liebig, Mark
item Cavigelli, Michel
item Del Grosso, Stephen
item Motavalli, Peter -
item Nelson, Kelly -
item Spokas, Kurt
item Singh, Bhupinder -
item Stewart, Catherine
item Ranaivoson, Andry -
item Strock, Jeffrey -
item Collins, Harold

Submitted to: Frontiers in Ecology and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 9, 2012
Publication Date: December 1, 2012
Repository URL: http://handle.nal.usda.gov/10113/56803
Citation: Venterea, R.T., Halvorson, A.D., Kitchen, N.R., Liebig, M.A., Cavigelli, M.A., Del Grosso, S.J., Motavalli, P.P., Nelson, K.A., Spokas, K.A., Singh, B.P., Stewart, C.E., Ranaivoson, A., Strock, J., Collins, H.P. 2012. Challenges and opportunities for mitigating nitrous oxide emissions from fertilized cropping systems. Frontiers in Ecology and the Environment. 10(10)562-570.

Interpretive Summary: Nitrous oxide (N2O) represents in many cases the largest single component of the greenhouse gas (GHG)budget of individual cropping systems and for the U.S. agricultural sector as a whole. Reducing N2O emissions from cropping systems remains a research frontier largely because of biophysical factors that set N2O apart from other agro-ecosystem N losses. Conservation management approaches that increase overall crop nitrogen (N) use efficiency – i.e., modification of fertilizer rate, source, placement, and timing - have in some cases been effective in reducing N2O emissions. However, the reliability of these approaches in reducing N2O emissions while maintaining crop yields across different locations and growing seasons is uncertain due to interactions of multiple factors that regulate several different N2O–producing processes in soil. While the underlying processes have been well-studied, our current understanding of key aspects and our ability to manage them, remain limited. Efforts to increase overall crop N use efficiency may not necessarily be effective for N2O mitigation because of the potential for several different soil production processes, the high variability and complexity of process controls, and the tendency for large pulse events. More effective strategies will require improved calibration of N fertilizer requirements to meet site-specific crop N demands using new crop sensing, fertilizer delivery, and other technologies, as well as improved understanding at the process level. Although the challenges are great, practices that mitigate agricultural N2O emissions will likely have broad co-benefits in reducing agricultural losses of all other reactive N forms, and therefore will enhance soil, water, and air quality in several ways. The aim of this article is to highlight the factors that make mitigation of N2O emissions from fertilized cropping systems such a difficult challenge, and to discuss how these factors and knowledge gaps limit the effectiveness of existing practices and therefore require new ideas and technologies. This information will be useful to policy-makers, farmers, and scientists in developing strategies for reducing GHG emissions associated with agricultural production.

Technical Abstract: Nitrous oxide (N2O) represents in many cases the largest single component of the greenhouse gas (GHG) budget of individual cropping systems and for the U.S. agricultural sector as a whole. Reducing N2O emissions from cropping systems remains a research frontier largely because of biophysical factors that set N2O apart from other agro-ecosystem N losses. Conservation management approaches that increase overall crop nitrogen (N) use efficiency – i.e., modification of fertilizer rate, source, placement, and timing - have in some cases been effective in reducing N2O emissions. However, the reliability of these approaches in reducing N2O emissions while maintaining crop yields across different locations and growing seasons is uncertain due to interactions of multiple factors that regulate several different N2O–producing processes in soil. While the underlying processes have been well-studied, our current understanding of key aspects and our ability to manage them, remain limited. Efforts to increase overall crop N use efficiency may not necessarily be effective for N2O mitigation because of the potential for several different soil production processes, the high variability and complexity of process controls, and the tendency for large pulse events. More effective strategies will require improved calibration of N fertilizer requirements to meet site-specific crop N demands using new crop sensing, fertilizer delivery, and other technologies, as well as improved understanding at the process level. Although the challenges are great, practices that mitigate agricultural N2O emissions will likely have broad co-benefits in reducing agricultural losses of all other reactive N forms, and therefore will enhance soil, water, and air quality in several ways. The aim of this article is to highlight the factors that make mitigation of N2O emissions from fertilized cropping systems such a difficult challenge, and to discuss how these factors and knowledge gaps limit the effectiveness of existing practices and therefore require new ideas and technologies.

Last Modified: 11/27/2014
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