This PhD thesis analyzes relationships betweenfarming activity and its local environment,precisely in the valleys. In these valleyenvironments that have specific features in termsof soils, topography and water flows modes,farming activities have to adapt, take advantage orcope with the natural features, as well as satisfyresource management requirements (such aswater and landscapes quality, riverbankmanagement, biodiversity...). The case study fieldis made of the three main valleys of a basin inwestern France, Maine river basin (Loir, Mayenneand Sarthe rivers). In these valleys areconcentrated several functions and social uses, inwhich agriculture represents one of the mostdominant elements. First, it is shown thatagriculture is specific in these valleys in terms ofenvironmental conditions and socio-economicalcontext, at different scales (from basin level tostudy areas level composed of a few municipalitiesin valleys), and throughout time (from 19th centuryuntil today). Then, interviews with farmers at thefarming system level give access to the variety ofassessments of a same local environment, namelythe bottom of the valley characterized by wet soilsand sloped sides. Specific land uses in the valleysare revealed from these investigations: kinds ofcrops, plots accessibility, grass forage types, etc.Finally, the selection of eight qualitative andquantitative criteria, such as distribution of plots,land use dynamics or nature of the relationship towater resources in the valley, has allowed us tobuild a typology of three types of farms, based onthe level of appreciation of the valley environmentby farmers.
