Nitrous oxide is a potent greenhouse gas (GHG) with a 100-year global warming potential 298 times greater than carbon dioxide. The Intergovernmental Panel on Climate Change (IPCC) estimate that agriculture contributes about 60% of total global anthropogenic N2O emissions, mainly due to nitrogen fertiliser use and emissions from animal waste. However, N2O fluxes from agricultural soils remain one of the most uncertain emission sources due to large spatial and temporal variability. This project seeks to determine the effectiveness of various mitigation options for N2O emissions from grass and spring barley production in Ireland. The information generated is urgently required to improve the national agricultural inventory for N2O emissions to take account of the range of soil types and climates in Ireland and facilitate a move towards country-specific (Tier 2) emission factors. In particular, the project will:
- generate N2O emission factors for manufactured fertilisers urea and calcium ammonium nitrate (CAN) for both grassland and spring barley production
- generate N2O emission factors for N stabilisers (also known as inhibitors) such as Agrotain, Nutrisphere-N and DCD (dicyandiamide) when applied with urea
- develop disaggregated N2O emission factors for different N sources, soil types, climate and time of year
- investigate the effect of fertiliser formulation on N cycle processes, in particular the ratio of N2O:N2 (nitrous oxide to dinitrogen, an environmentally-benign gas).
The N2O project in AGRI-I will be closely aligned with a project on Sustainable nitrogen fertiliser use and disaggregated emissions of nitrogen (SUDEN) funded by the Department of Agriculture, Food and the Marine, which is quantifying N uptake, N leaching and ammonia volatilisation in the same sites and treatments.