Potentie van grasraffinage op melkveebedrijven: Modelanalyse van de effecten van grasraffinage op de nutriëntenkringloop en economische prestaties van melkveebedrijven

This report analyses the effects of grass refining using Dairy Wise for three typical Dutch dairy farms: an intensive farm on clay soil and two extensive farms on peat and sandy soils. The initial situation was compared with a scenario in which five hectares of grassland per farm are allocated to grass refining. The results show that grass biorefining alters the availability and composition of roughage, which affects the purchase and sale of feed (including concentrates) and thereby the farm’s economic performance. Grassland use also changes, which has implications for the required quantity and composition of mineral fertilizers. The removal of protein from the farm via grass juice reduces, depending on the level of concentrate purchases, the share of home-grown protein. The changes in nutrient flows lead to lower ammonia and greenhouse gas emissions. Overall, the model analysis shows that the application of grass refining results in a positive economic outcome, based on compensation for land use and grass juice, lower contracting costs, reduced concentrate feed costs, and lower manure disposal costs. Grass refining can therefore be considered a promising strategy to improve both nutrient use efficiency and the profitability of dairy farms. However, validation under practical farming conditions is required to determine how these model outcomes translate to farm-specific practices and results.