Experimental economics and co-design of the PES with the farmers of Tremblay-Omonville

Through of one-to-one meetings with the farmers of the Tremblay-Omonville catchment, the SERPN defined the objectives of practices for setting up plant cover between two crops. Furthermore, Sara Hernandez Consulting (SHC) organized experimental workshops to test the role of collective action in achieving the Winter Incoming N Balance (WINB) targets to reduce soil nitrate levels.

Fanny Claise, SHC's junior consultant, developed a “public good” game to identify the level of farmers' preference for accepting a payment that would take into account collective achievements or collective efforts towards changing practices to improve water quality. In other words, the game of the “public good” can reveal altruistic attitudes of individuals, cooperative and competitive tendencies (opportunistic behaviour) towards a common goal.

Twenty farmers participated in the game and some players participated at the same time as farmers from Paris. At the end of the game, a discussion between the experimenter and the farmer brought out some interesting outcomes. This type of game has the advantage of facilitating dialogue with farmers who are motivated to continue their efforts (plant cover planting) in order to improve their WINB. Most were convinced of the role of group action in achieving a collective result for improving water resources in the catchment area. According to participating farmers, however, the allocation of this payment must not be too restrictive and the payment must be economically attractive and fair.