Résumé
Characterization of the spatial organization of agricultural practices is required for an assessment of the risks of diffuse pollution by pesticides. In the case of a vineyard catchment in Southern France, the authors hypothesized that the diversity of weed control practices is spatially organized at different levels. The practices were characterized on the basis of interviews with 27 vine-growers belonging to two different wineries. Three practices were differentiated according to the intensity of herbicide use. The results showed that field characteristics related to inter-row width play an important role in the weed control choices but fully make sense in the context of the holding, where choices of practices are related to the size of the workforce and the structure of the vineyard. The supply basin of a co-operative winery appeared as a third level of organization of the practices as the wineries direct the structure of their members' vineyards through their incentive policy. Finally, the possibility of using the results to localize weed control practices is discussed.