Nitrous oxide emissions from landfill cover soils in Sweden

Emissions of nitrous oxide measured at 4 landfill sites were found to be higher where sewage sludge was used as a landfill cover, ranging from -0.011 to 35.7 mg N₂O-N m^-2 h^-1. From landfill sites covered with mineral soils, N₂O-emissions ranged from ^-O.0017 to 1.07 mg N₂O-N m^-2 h^-1. However, extrapolation to the national level showed that sewage sludge could only be a minor source of nitrous oxide, since the amounts of sewage sludge are too small to give rise to any considerable fluxes compared with other sources. Nitrous oxide emissions from sewage sludge are comparable to emissions from most fertilizers, i.e., the N₂O-emissions are around 1% of the N-input per year.