Erfassung gasförmiger Emissionen vom Auslauf einesJungviehstalles mittels aktiver Probenahmehaube

Open stable systems with outdoor yards are used in organic cattle farming. Until now there are no emission factors in Germany for outdoor yards of dairy barns or of cattle barns generally. The measuring of the emission potential of gaseous substances (NH3, CO2, N2O and CH4) is difficult because of the size of the outdoor yards and the direct access by climate. One possibility to measure those emissions is the use of an active sampling hood. The sampling hood provides defined laminar exhaust airflow. The product of flow rate and concentration results in the emission mass flow. In a preliminary study six cattle in calf with a total of 7.19 GV had access to an outdoor yard. This was divided virtually in a 9 x 11 a 1 m² grid. To each m² a dirt level (clean, slightly, medium and heavily soiled) has been assigned. The grid area was sampled randomly. The influence of a scraper was investigated, too. The levels of dirtiness were allocated to the NH3 emission mass flows. Based on the rating the results of the random samples were transferred on the partial area of the entire outdoor yard. The outcome of this is an emission factor for NH3 of 3.02 kg/GV*a for the outdoor yard before the scraper was used and 2.79 kg/GV*a afterwards. The preliminary results show that measuring NH3 emissions by an active sampling hood is practicable for the use at outdoor yards of cattle barns.