This thesis reports on the social transformations brought by the development of intensive irrigation from groundwater and outlines a more global analysis of the processes of modernization of rural areas in Morocco. It contributes to the research field of critical agrarian studies and uses a "modernity-present" approach. Based on 15 months of empirical work combining observations, non-directive interviews, semi-structured interviews and focus groups, this study was conducted in rural communes of the province of El Hajeb where farmers moved from rain-fed agriculture to agriculture partially or totally irrigated by groundwater in the 1980s. By focusing on the processes of appropriation and reappropriation of land since access to individual water, and by disentangling the material and ideal modalities of appropriation, it was possible to grasp how access to water modified the relationship to land in territories undergoing land reform. This research shows that the increase in social differentiation linked to the rise of private irrigation has been accompanied by socio-economic differentiation in access to water, leading to the marginalization, but not the exclusion, of a large part of the rural population, and the reinforcement of inequalities in the rural areas studied. These dynamics lead to tensions that reveal conflicts of modernity that call for the need to consider the aspirations and ideals of the different social groups coexisting in the studied areas. This research has, moreover, emphasized an ideal of modernization through individual agricultural water that remains linked, today, to the groundwater economy model, in a context, admittedly, where the pressure on water resources continues to increase, but where the ideal of the actors meets the ideal of Moroccan State advocating a continuity of a policy of resource management through supply.