Monitoring van methaan-, ammoniak- en lachgasemissies uit melkveestallen : Praktijkmetingen in de periode oktober 2018-oktober 2020

Between October 2018 and October 2020 measurements have taken place on 18 dairy farms in The Netherlands based on which their ammonia- (NH3) and methane (CH4) emissions were determined. With the measurement equipment, an emission estimation was made per day and compared with a reference measurement. The aim of this study was to determine the methane emissions and its variation from dairy houses in the Netherlands. Besides that, an aim was to find relations with farm management factors. Another aim was to investigate how such a measurement system could support farmers to apply measures in order to reduce ammonia- and methane emissions. The mean emission ± standard deviation was 13,8 ± 3,2 kg NH3 per animal place per year and 193 ± 56 kg CH4 per animal place per year based on the reference measurements. Based on thedaily averages (from the continuous measurements), the average ammonia emissions were 12,0 ±2,9 kg per animal place per year and the average methane emissions 184 ± 50 kg per animal place per year. Based on continuous measurements, the variation in methane emissions was 27% between farms and 29% within farms (i.e. the variation between days). The outside temperature is found to be a good predictor for the ammonia emissions pattern throughout the year. In addition to that, the CH4-CO 2 ratio at concentration level of house air can be used as a predictor for the total methane emission of a certain farm. Quantifying emission levels by a measurement system can help the farmer to implement farm specific measures