title: Using nitrification inhibitors to mitigate agricultural N2O emission: a double-edged sword?
abstract: Nitrification inhibitors show promise in decreasing nitrous oxide (N2O) emission from agricultural systems worldwide, but they may be much less effective than previously thought when both direct and indirect emissions are taken into account. Whilst nitrification inhibitors are effective at decreasing direct N2O emission and nitrate (NO3-) leaching, limited studies suggest that they may increase ammonia (NH3) volatilization and, subsequently, indirect N2O emission. These dual effects are typically not considered when evaluating the inhibitors as a climate change mitigation tool. Here, we collate results from the literature that simultaneously examined the effects of nitrification inhibitors on N2O and NH3emissions. We found that nitrification inhibitors decreased direct N2O emission by 0.2-4.5 kg N2O-N ha-1(8-57%), but generally increased NH3emission by 0.2-18.7 kg NH3-N ha-1(3-65%). Taking into account the estimated indirect N2O emission from deposited NH3, the overall impact of nitrification inhibitors ranged from -4.5 (reduction) to +0.5 (increase) kg N2O-N ha-1. Our results suggest that the beneficial effect of nitrification inhibitors in decreasing direct N2O emission can be undermined or even outweighed by an increase in NH3volatilization.
authors.affiliation: Crop and Soil Science Section, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Shu Kee
authors.initials: SK
authors.lastname: Lam
authors.affiliation: Crop and Soil Science Section, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Suter
authors.affiliation: Crop and Soil Science Section, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Arvin R
authors.initials: AR
authors.lastname: Mosier
authors.affiliation: Crop and Soil Science Section, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
authors.forename: Deli
authors.initials: D
authors.lastname: Chen
mesh_terms: D000383:Agriculture; D057231:Climate Change; D005308:Fertilizers; D058465:Nitrification; D009609:Nitrous Oxide
chemical_list: D005308:Fertilizers; D009609:Nitrous Oxide
keywords: agriculture; ammonia; climate change mitigation; indirect greenhouse gas; nitrification inhibitor; nitrous oxide