We describe a simple model of the dynamics of adoption of agri-environmental measures by farmers in Europe. Farmers choices are based on their evaluation of the economic advantages of taking environmental premiums in exchange for environment friendly practices, plus imitation terms taking into account the information that they get from neighbours which have already made their own choice. We show that under a large set of social network topologies and hypotheses on distribution of farmers characteristics, the outcome of the social processes, namely premium uptake rate, depends upon local characteristics of farmers and their network. It is not directly related to average characteristics. Some conclusions and recommendations about policy implementation can then be driven.