The introduction of new cultures and techniques in the farmers' productive system depends not only on the environmental constraints (precipitation, outline, soils) but also on the way the farmers combine their personal beliefs with the teachings of the technicians, based on an autonomous production of knowledge. Any introduction of a new product in the system of "sequeiro" is conditioned by its characteristic of producing fodder. The introduction of "congo" beans in the farming systems was inglorious due to the adversities of the natural environment but it was accompanied by the appraisal of the farmers who always overrate the species' economic "plasticity" (the capacity of producing food, wood, the preservation of the soils and the non-competition with other species) around the fact of being able to produce fodder. As a producer of an autonomous knowledge the farmer takes on the constraints of the environment in an objective way but produces a subjective reading when understanding the environment as a whole for the simple reason that he does a selective integration of the elements into that knowledge. The process of innovation encounters, as well, other factors of supreme importance such as the accessibility to the factors of production in what concerns the watering intervals, the pieces of the machines, the "drugs" and the credit. The implementation of the "drop-by-drop" system and the production of vegetables among the younger farmers is related to the fact that these adhere more easily to the proposals of the extensionists and agricultural technicians and, consequently, are able to dilute the elders' beliefs which are, at the same, in favor of the conservation of the power/ knowledge instituted in the traditional system of flooding associated with to the complex of the "trapiche". These processes enclose many advances and recoils, "involutions" that are no other than the state of the system in a given moment, in the actuality of the farmers' actions as managers of minimal resources.