The dynamics of N2O near the groundwater table and the transfer of N2O into the unsaturated zone: A case study from a sandy aquifer in Germany

A multiple regression for the monthly N2O amounts in the exchange zone could explain 66% of the yearly variation. The significant variables were NO3−, CO2, pH, and O2. Therefore, a combination of the land use (NO3−), the geochemical boundary conditions (pH) and the type of denitrification reaction (O2 and CO2 indicate the importance of a heterotrophic denitrification process) governed the N2O dynamics in the surface groundwater of the FFA and its transfer into the unsaturated zone.