Optimizing the environmental performance of agricultural activities: A case study in La Boulouze watershed

This paper introduces a method to optimize the environmental performance (EP) of agricultural activities, defined as the distance between the 'environmental' state of a system at a specific time or on a specific period and a 'high environmental performance' state to reach. Focus is on water management at the watershed level with three criteria: nitrogen, sediments (water quality) and water yields (water quantity). The purpose is to provide a new land-use plan. The originality of the method lies in the coupling between an agro-hydrological model, the soil and water assessment tool (SWAT), and the goal programming (GP) optimization method. Modeling is used to define the initial situation of the system and to generate data for the optimization. Goal programming is implemented to relocate farming systems in the watershed using a binary decision variable. The method is implemented on the La Boulouze watershed (South West of France). The results are an improvement of the EP, but the 'high environmental state' is not reached. The main land uses changes are the decrease of the sunflower-wheat farming system in favor of the meadows.