Graslandmanagement voor reductie van methaan en ammoniak: Resultaten analyse KringloopWijzer 2021 van 15 pilotbedrijven: jaarrapport 2

This project focuses on an integrated approach to reduce methane (CH4) and ammonia (NH3) emission on dairy farms, with changes in grassland management as a measure. For 15 pilot farms using with grazing cattle, the current efficiency and corresponding CH4 and NH3 emissions were calculated. This was done using the Annual Nutrient Cycle Assessment (ANCA) from 2021, using more detailed detail input on grassland related to CH4 and NH3 emission and applying adapted emission factors for CH4 (A), simulating single (B) and combined (C) effects of farm characteristics and management strategies on emissions. This overview shows that increasing grazing hours and increasing fresh grass intake can contribute to simultaneous reduction of CH4 and NH3 on dairy farms. The crude protein level of additional roughage feeding plays an important role in reducing NH3 emission. Fresh grass, especially in spring, remains an important management tool. It is expected that CH4 emission can be reduced by 3-12% on dairy farms with grazing practices through management measures. This report describes the results of the analysis of 15 pilot farms in the dataset of 2021, as an exploratory study. Since the selection of dairy farms is not perse representative for the sector, the results cannot directly be translated to practice.