Denitrification in subsoils and groundwater
Denitrification is one of the main mechanisms for the reduction of nitrate (NO3-) movement through subsoils and groundwater. However this process may also lead to emissions of the greenhouse gas, nitrous oxide (N2O), rather than the environmentally benign N2. Understanding the microbial denitrification process within subsoil/groundwater will lead to a better understanding of the fate of NO3- delivery to groundwater and may also lead to management procedures for reducing both N2O emissions and NO3- leaching. The movement and transformations of NO3- from below the rooting zone to groundwater within agricultural systems is not yet well understood. The data generated from this project will assist in the prediction of NO3- occurrence in receiving waters, environmental risk assessment and contribute knowledge to Ireland’s derogation case under the Nitrates Directive and assist the achievement of Water Framework Directive objectives. Finally the N2O/N2 emissions quantified can be used to refine Irish greenhouse gas emission inventories under the Kyoto Protocol. This project quantifies NO3- reduction and indirect N2O emissions to atmosphere via subsurface denitrification while passing through and from the landscape to the surface waters.
Project coordinators: Adjunct Assistant Prof. Paul Johnston & Dr. Karl Richards (Teagasc)