Diversité du territoire d'exploitation et sensibilité aux aléas climatiques : exemples d'élevages laitiers en Auvergne

A major constraint in the management of forage systems is constituted by the climatic hazards. By adjusting the utilization of his lands during the season, a farmer may reduce the sensitivity of his forage system to them. We have sutdied the link between these adjustments and the diversity existing within the farm lands. The study was made on seven animal farms during the 2002 season : we analysed the reasons for which the farmers decided to make these adjustments along the season and we tried to find out how the diversity of the lands influenced them. There are three ways in which these farmers adjusted the utilization of their lands. One is limited to a poorly diversified farm land ; the two others correspond to well-diversified lands, but where the flexibilityof land utilization against the climatic hazards was different : either a pre-ordained flexibility at planning, or a flexibility of management during the season.The latter case illustrates the underlying assumption that land diversity is an asset in view of the possibilities it gives of adjustments for climatic hazards. / Un territoire d'exploitation varié ( végétation, altitude ou exposition) constitue un atout pour limiter la sensibilité du système fourrager aux alés climatiques. Il permet de procéder à des ajustements dans l'utilisation du territoire. Pour vérifier cette hypothèse , en 2002, un suiviauprès de sept exploitations d'élevage a permis d'étudier quatre modalités théoriques d'ajustement de l'utilisatin du territoire. Elles sont dépendantes de la diversité du territoire et de l'importance des règles de pilotage mobilisées par l'éleveur en cours de campagne.