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Mitigating nitrous oxide emissions from an irrigated cropping system


Agricultural production in the western U.S. is an important part of the global food supply. However, due to concerns over impacts of agricultural greenhouse gasses on the global climate, there is a need to test potential mitigation strategies, especially for nitrous oxide (N2O) from irrigated cropping systems in semiarid environments. 

In a paper recently published in the Soil Science Society of America Journal, researchers report N2O emissions from a dairy forage rotation (silage corn-barley-alfalfa) in south-central Idaho that received various nitrogen sources, including conventional granular urea and an enhanced-efficiency fertilizer (SuperU, a stabilized granular urea with urease and nitrification inhibitors).

During corn production, the team found that cumulative N2O emissions were 53% lower with SuperU when compared with granular urea, and crop yields were unaffected. But when SuperU was used the following year with barley, cumulative N2O emissions were the same as those from granular urea. Furthermore, there was no lingering effect of SuperU on emissions when alfalfa was the subsequent crop. Overall, N2O-N emission losses as a percentage of total N applied were very low at ≤ 0.21%.

This work demonstrates that SuperU can reduce N2O emissions from irrigated cropping systems, but the results suggest that there is a crop-dependent effect. The study is currently being replicated for confirmation.

Read the full paper in SSSAJ. Free preview June 12- June 19