The characterization of actual crop rotations on a large territory is a major challenge for local stakeholders in order to understand agricultural impacts on natural resources, e.g., nitrate leaching (Beaudouin et al., 2005). Although various mathematical descriptions and simulations of crop rotations have been proposed (e.g., Castellazi et al., 2010), few models propose to reconstruct actual crop sequences and to simplify their diversity in a reasonable number of crop rotations. The aim of this work was thus to combine modelling and farm interviews to characterize crop rotations which were representative of different soil characteristics and farming systems over a whole agricultural area of 70,000 ha.