Mitigating Nitrous Oxide Emissions from Corn Cropping Systems in the Midwestern U.S.: Potential and Data Gaps
2014
Decock, Charlotte
One of the unintended nitrogen (N)-loss pathways from cropland is the emission of nitrous oxide (N₂O), a potent greenhouse gas and ozone depleting substance. This study explores the potential of alternative agronomic management practices to mitigate N₂O emissions from corn cropping systems in major corn producing regions in the U.S. and Canada, using meta-analysis. The use of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) in combination with the nitrification inhibitor Dicyandiamide (DCD) was the only management strategy that consistently reduced N₂O emissions, but the number of observations underlying this effect was relatively low. Manure application caused higher N₂O emissions compared to the use of synthetic fertilizer N. This warrants further investigation in appropriate manure N-management, particularly in the Lake States where manure application is common. The N₂O response to increasing N-rate varied by region, indicating the importance of region-specific approaches for quantifying N₂O emissions and mitigation potential. In general, more data collection on side-by-side comparisons of common and alternative management practices, especially those pertaining to N-placement, N-timing, and N-source, in combination with biogeochemical model simulations, will be needed to further develop and improve N₂O mitigation strategies for corn cropping systems in the major corn producing regions in the U.S.
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