Abstract
Over the last years there has been a significant development of bio-economic models, especially those integrating biophysical (called also agronomic or cropping system models) models and economic mathematical programming models. This development was enhanced by the conjunction of several factors such as the multiplicity of objectives of new agricultural policies, the increase of demand for multi-disciplinary approaches for integrated assessment, the call for more dialogue and cooperation between scientists from diverse disciplines... However, this rich body of literature on empirical applications of bio-economic models was not followed by a clear definition of their conceptual and theoretical framework. Indeed, there is not enough literature regarding the relations between this kind of models and the economic theory, their main interest compared to conventional economic approaches, their specifications and contributions in strengthening collaboration and improving integration between different disciplines... The aim of this chapter is to develop some conceptual and theoretical issues related to the bio-economic models and to present the suitable way to use this type of approach for modelling the relations between agriculture and environment and more largely for the integrated assessment.