Experimental determination of emission factors and the greenhouse gas budget of grazing systems in Switzerland: Final Report Extended Summary (Project on behalf of the Swiss Federal Office for the Environment FOEN).
Experimental determination of emission factors and the greenhouse gas budget of grazing systems in Switzerland: Final Report Extended Summary (Project on behalf of the Swiss Federal Office for the Environment FOEN).
The present study analyzed the greenhouse gas flux measurements of a grazed pasture system for dairy cows in western Switzerland over five years. Based on the evaluation and the corresponding uncertainties the pasture has to be considered as near carbon-neutral and as a small source for CH4. However, the pasture was found to be a considerable and significant source of N2O attributable both to grazing excreta and to fertilizer spreading. The developed partitioning procedure allowed the determination of excreta-related and fertilizer-related emission factors. While the fertilizer-related emission factor was on average close to the corresponding IPCC default value, the excreta-related factor was significantly lower than the presently used default value of 2%. It could also be shown that there is a clear difference in the individual emission factors for urine and dung patches on the pasture. For the development of country-specific emission factors for Switzerland, a combined use of process-based modelling and experimental results is recommended.
