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
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.
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.