It consists in adding more than one microorganism admittedly beneficial to plants, in order to maximize the contribution of both to the plant. It combines well-known practices to the producers: the inoculation of soybean (or bean) seeds with nitrogen-fixing bacteria, namely rhizobia that will act through symbiotic fixation of nitrogen (BFN), and with the use of Azospirillum, a bacterium known for its action promoter of growth in grasses, but also helping for BFN effect and development of beans, and soybeans.