In both industrialized and non-industrialized countries, the economic environment faced by farmers is undergoing profound changes due to uncertainty and economic liberalization. Decision-making processes related to farm management are more complex and diversified than ever. Normative models of management and research offering 'one best way' solution are no longer efficient in such a context. A new approach is presented here, based on (i) the concept of action model, (ii) a sectoral analysis of farm management, (iii) general frameworks of the decision-making processes adapted to complex problems like work organization and (iv) modelling and simulation to stimulate farmers' reasoning rather than giving them recommendations. This approach is illustrated by two cases dealing with work organization in rice-based farming systems. The first one is in Camargue (France) where rice establishment in spring is critical because of cold temperatures. We show how farmers organize their work from ploughing to seeding, how we can model and simulate this specific organization, and how the advice process is structured around this knowledge. The second case is in the Senegal River delta (Senegal), where farmers collectively manage irrigation schemes and try to implement a double cropping of rice using contractors for land preparation and harvest. This plurality of actors increases uncertainty and makes the coordination necessary between them more complex. In this case, advice is mainly an aid to formalize technical and organizational problems, as no modelling tool is yet available to represent these situations. The interests and limits of the approach, as well as further research perspectives, are discussed.