Nitrous oxide emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape near Bjerringbro, Denmark, to investigate the main sources of variations in N2O emissions. Emissions were measured using four types of static chambers. Intensive sampling was done during April 2009 when chambers were installed at nine locations or fields to cover different crops and topography. During the experiment, slurry was applied to three of the fields. N2O fluxes were calculated from chamber concentration data using software that allows for non-linear regression of observed gas accumulation in the chambers. N2O emissions during the spring 2009 period were relatively low for all land use types. Emissions increased after slurry application to the wheat fields. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil moisture conditions due to the absence of rain fall during the previous four weeks. During the equivalent spring period of 2008, N2O fluxes were higher than in 2009, as was soil moisture content, indicating the importance of the climatic regime on N2O fluxes.
Proceedings From the International Conference on "nitrogen & Global Change, Key Findings - Future Challenges", 2011