AgriBMPWater: systems approach to environmentally acceptable farming

This project aims at providing planners with a grid which would allow a comparison between Best Management Practices (BMPs) in terms of environmental efficiency, economic cost and potential acceptability by farmers. A comparison between different existing or simulated BMPs (Best Management Practices) has been carried out through a cost/effectiveness assessment along with the study of their acceptability by farmers on seven European watersheds in a multidisciplinary framework which includes eleven research teams. Effectivity has been assessed as the evolution of water quality resulting from BMPs' implementation in experimental watersheds. Particular efforts is being carried out to improve BMPs representation in hydrological models, as they can take various forms from landscape structures modifications to agronomic recommendations. Spatial modelling, at various scales, is used to define critical areas where efforts should be concentrated. For costs, efforts concern the evaluation of both direct and indirect costs induced by BMPs implementation. When studying diffuse pollution, individual contributions and de-pollution costs were not known and had to be assessed. Direct costs are estimated through the definition of contract menus in a Principal/Agent modelling framework, or, depending on the available data, with linearly optimised profit functions. Indirect costs have been considered as being the impact of BMPs on all other branches of the economy and were evaluated by using a general equilibrium model. A cost/effectiveness ratio was calculated for each studied BMP, allowing a comparison of possible alternatives. Unfortunately farmers tend not to apply BMPs as would be desirable. Possible explanations include their poor commitment to environmental improvements and their practice of insufficiently implementing BMPs. Extensive interviews have been carried out to account for the social dimension of farmers' decision making process. In addition, complementary interviews with land managers helped defining practices already implemented and problems that have already been encountered. This work aims at defining new negociative implementation methods which will be evaluated in a demonstration project involving both local land managers and farmers. / Ce projet a pour but de fournir une grille qui permette la comparaison entre les meilleures pratiques de gestion en terme d'efficacité environnementale, coût économique et acceptation potentielle par les agriculteurs.