In Latin America, the solidarity economy has born in the urban sector and particularly around initiatives of cooperative nature. In Brazil, it is object of instruments of public policy on the part of the National Secretariat of Solidarity Economy, supporting in particular forms of self management of the means of production. Recently, a reflection about solidarity economy practices in rural area has emerged. It has to see with activities that are not only established in cooperative enterprises, such as the experiences of handling of resources or common properties, the solidarity credit practices and the agro-ecological markets. This extension of the field of application of the notion of solidarity economy leads to consider the diversity of its theoretical references. Based on the analysis of the origins and modalities of some cases of solidarity economical practices in the Brazilian rural area, the communication examines the conceptual bases that can be used to interpret the advances and the limits of these experiences. The work mobilizes thus the economic categories of reciprocity, redistribution and exchange identified by K. Polanyi and the notion of reciprocity structure proposed by D. Temple. The quarrel questions the explicative or clarifying character of the notion of embeddedness and looks to elements of reply from the situations disclosing an interface of systems between the logic of the reciprocity and the logic of the exchange.