The area of Lake Aloatra faces a growing population, a stagnation of rice production and an increase in crop land which are less fertile and subject to erosion. To promote sustainable agriculture research and development projects promote new agricultural techniques based on conservation agriculture including no-tillage practices. Increase in cultivated area affected by these new techniques is real but modest. Questions are raised about the adequacy of support provided to farmers, especially by advisory services. The objective of this paper is to question the adequacy of advisory services regarding to the organizational and technical changes induced by the adoption of conservation agriculture and to propose improvements of the advisory system regarding to the local constraints and opportunities (skills and creation of knowledge for advisors, funding, interactions between researchers and advisors, etc..) The work is based on surveys of farmers and stakeholders involved in advisory activities. The results show the dominance of technical advice provided by a project mainly dedicated to the promotion of conservation agriculture and based on the recommendations of a bio-physic research, but also the recent willingness to promote advice that addresses the complexity of farming system in interaction with the proposed technical changes. The results question the advisory method mobilized to achieve the goals but also the capacity of advisors to develop co-constructed advice. They also show the dominance of advisory providers and projects to orient the advisory activities, the role of research in the provision of technical-economic references for advisors and in the development of advisory methods, and the small ability of farmers to influence the choice that are made. They question the sustainability of the advisory system in a context of funding of advisory system by foreign aid. (Texte integral)