A new Swiss inventory of ammonia emissions from agriculture based on a survey on farm and manure management and farm-specific model calculations

Existing emission inventory approaches mainly rely on expert judgement for information on farm and manure management. To detect the relatively small changes of total annual ammonia (NH3) emissions required under the Gothenburg Protocol, expert judgement is considered insufficient. We present, therefore, here a new Swiss NH3 emission inventory based on a detailed representative stratified survey on farm and manure management conducted on 1950 farms. The survey data was used to calculate NH3 emissions with the emission model DYNAMO for each farm participating in the survey. This allowed the effects of the variability of farm and manure management parameters among farms on the NH3 emissions to be fully taken into account. Weighted emission factors per animal for 24 livestock categories and 36 farm classes were used to upscale to the national inventory. The stratified sampling and the individual farm calculations allowed the comparison of emissions from specific regions and altitudes and the study of the variability among farms. The new emission inventory approach permits a more detailed analysis of the regional distribution of NH3 emissions as well as a more robust and standardised monitoring of the future development of emissions.