Auteur: Oenema J., Hilhorst G.J. and Van Ittersum M.K.
Jaar van uitgifte: 2015
In the Netherlands, more than 60% of agricultural land is used for dairy farming. Grass is the most important crop, followed by maize silage. To explore possibilities to increase nutrient-use efficiency and reduce nutrient losses, the method of prototyping a combination of system modelling and system implementation was applied on the experimental farm ‘De Marke’. To promote development and adoption of similar systems in commercial dairy farming, the project ‘cows & opportunities’ (C&O) was initiated in 1999 to bridge the gap in nutrient-use efficiency between experimental farms and commercial pilot farms. Total nitrogen (N) and phosphorus (P) application rate declined from 530 in 1998 to 400 kg N ha‑1 in 2013 and from 57 in 1998 to 48 kg P ha‑1 in 2013. Average grass dry matter yields were 11 Mg ha‑1 but with a huge variation amongst pilot farms. Substantial improvements in grassland management are possible on many commercial dairy farms, but strategies differ amongst farms.