Estimating the impact of changing fertilizer application rate, land use, and climate on nitrous oxide emissions in Irish grasslands
2014
Kim, Dong-Gill | Rafique, Rashad | Leahy, Paul | Cochrane, Mark | Kiely, Gerard
AIM: This study examines the impact of changing nitrogen (N) fertilizer application rates, land use and climate on N fertilizer-derived direct nitrous oxide (N₂O) emissions in Irish grasslands. METHODS: A set of N fertilizer application rates, land use and climate change scenarios were developed for the baseline year 2000 and then for the years 2020 and 2050. Direct N₂O emissions under the different scenarios were estimated using three different types of emission factors and a newly developed Irish grassland N₂O emissions empirical model. RESULTS: There were large differences in the predicted N₂O emissions between the methodologies, however, all methods predicted that the overall N₂O emissions from Irish grasslands would decrease by 2050 (by 40–60 %) relative to the year 2000. Reduced N fertilizer application rate and land-use changes resulted in decreases of 19–34 % and 11–60 % in N₂O emission respectively, while climate change led to an increase of 5–80 % in N₂O emission by 2050. CONCLUSIONS: It was observed in the study that a reduction in N fertilizer and a reduction in the land used for agriculture could mitigate emissions of N₂O, however, future changes in climate may be responsible for increases in emissions causing the positive feedback of climate on emissions of N₂O.
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