Previous studies on the biodiversity productive capacity emphasized that crop diversity increases crop yields. Here, we focus on the productivity of crop diversity and permanent grasslands for cereals and milk. Using GMM, we estimated joint production functions using a sample of 3960 mixed farms of the FADN from 2002 to 2013. We highlight that permanent grasslands enhance crop production. We confirm that crop diversity increases crop and milk yields. However, both biodiversity productive capacity are substitute inputs. We found that biodiversity productive capacities influence variable input productivities. These results emphasize the potential adaptations of farmers’ choices to environmental measures.