Assessing Agricultural Peatland Emissions of Nitrous Oxide in Ireland

Peatland is an important storage of carbon (C) and nitrogen (N) on the earth surface. They have played a vital role in regulating the global climate through their capacity for C and N sequestration. Human activities including peatland drainage, burning, and conversion for agriculture transform peatlands from C sinks into greenhouse gas (GHG) sources. In Ireland, approximately 20% of the land area is peatland, over 95% of them have been degraded through anthropogenic activities. To assess the impact of peatland management on nitrous oxide (N₂O) emission, this study utilised the LICOR auto chamber and smart chamber coupled with state-of-the-art portable gas analysers to determine the N₂O emissions from grass-based agricultural peatland in Ireland. The site-specific characteristics that drive GHG production and can act as proxies for emissions (water table height and nutrient status) were also explored. Refined emission factors (EFs) were developed for N amendments applied in both drained and rewetted peatland. N amendments including mineral N fertiliser, cattle urine and sheep urine were applied to simulate real agricultural activities on peatland. The results obtained so far showed that peak N₂O emissions occurred on the day of N application and in the presence of rainfall. The cumulative N₂O emission showed significant difference between both drained and rewetted peatland. The outputs of this work will directly contribute to the Ireland National Inventory Report and provide insight for climate mitigation and peatland rehabilitation activities.