Pilotage de la production et aide à la décision stratégique : le cas des exploitations en grande culture
Abstract
Production management and stratégie décision support. The case of arable farm. For farmers, the present question of redefinition of the new CAP implies redefinition of both strategic decisions and management practices. Most existing production models and decision support Systems dealing with tactical and operational decision levels seem to be inadequate to solve these problems. In this perspective, we suggest that a pertinent way of setting the problem involves emphasizing the farmer's vision to build evolution projects. According to the analysis of practices in arable farms, we assume that farmer's production management rests on an integrated vision of different decision levels (from operational to strategic ones) : for each crop, the farmer conceives a set of coordinated decision rules for the successive steps of technical management ; but these rules are strongly dependent on transversal levels of decision which deal with the necessary sol- ving of conflicts between activities for the allocation of limited resources (labour, equipment, money..). This vision structures production management by the way of plans of action which raise the problem of coordination. So, we design a framework to forma lize the production management. We assume that the formalization of a far- mer' s decision rules and the simulation of their resuit s in a set of scenarios may help the f armer to have a new look on his own mangement and may lead him to imagine new ways of managing production. Thus, we conceive Decision Support Systems which expand the decision maker's reasoning. These D.S.S. are based on managerial knowledge representation (the decisional model) and on simulation processing. The decisional model uses frames, production rules and specifie language. We implement tools that run decisional models and estimate their effects for several climat ic scenarios. The aim is to favour an interactive and cooperative approach between farmers who have resolved the problem and the adviser. This approach has been tried on problems such as wheat crop management and work organization in relation to the choice of equipment I labour levels. For this last point, an experimentation has been carried out since 1990 with groups of advisers and farmers. It showed the relevance of the approach as a support to imagine new technical and economical ways of organizing work and reflect on farms equipment. Another project is still in development for more rational irrigation management.
L'objet de cet article est de présenter une démarche de modélisation de la production agricole dans une perspective d'aide à la décision stratégique. Cette démarche vise à privilégier une problématique de conseil basée sur la prise en compte des modalités pratiques de gestion des agriculteurs. L'objet de la première partie est de montrer à partir d'exemples les logiques qui structurent l'activité de gestion de production. Dans une deuxième partie, nous abordons la nature des interconnexions qui s'opèrent entre gestion courante et décisions stratégiques. Une troisième partie présente une démarche de conseil basée sur des systèmes d'aide à la décision qui permettent d'expérimenter par simulation des modèles de gestion et de construire des projets d'évolution d'exploitation, argumentes sous l'angle de leur intérêt économique et de leur cohérence vis-à-vis des contraintes de l'action.