Background: The Thünen Institute of Climate-Smart Agriculture annually compiles the national inventories of greenhouse gases, air pollutants and dusts from agriculture. For this purpose, ammonia emissions are calculated from activity data using emission factors. The emission factor for spreading of biogas digestates has been derived by analogy because literature values are not available.
Objective: The emission factor currently used for biogas digestates will be checked experimentally and be related to emission factors of cattle and pig slurries. Field spreading of these organic fertilizers will be simulated in lab incubation experiments and ammonia emissions will be measured. Results from these experiments are expected to be integrated into the official emission reporting.