Estimating the impact of changing fertilizer application rate, land use, and climate on nitrous oxide emissions in Irish grasslands
Wondo Genet College of Forestry and Natural Resources, Hawassa University, Shashemene, Ethiopia; HYDROMET, Centre for Hydrology, Micrometeorology and Climate Change, Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, 73019 OK, United States; Environmental Research Institute, University College Cork, Cork, Ireland; Department of Civil, Structural and Environmental Engineering, Cork Institute of Technology, Cork, Ireland
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. [Figure not available: see fulltext.] © 2013 Springer Science+Business Media Dordrecht.
agricultural emission; biogeochemistry; climate change; climate effect; climate feedback; fertilizer application; grassland; land use change; nitrous oxide; Ireland