EN
The aim of this study was to increase the biological fixation of nitrogen by the application of co-inoculation with Azospirillum brasilense T60 and Sinorhizobium meliloti Bp bacteria in lucerne (Medicago sativa L.) and investigate to what extent the Azospirillum brasilense strain is appropriate for the co-inoculation in lucerne. The obtained results revealed a stimulating effect of the simultaneous inoculation of the alfalfa with Sinorhizobium meliloti and Azospirillum brasilense strains. The applied co-inoculation was found to exert a favourable impact on: the increase of fresh green matter and plant roots, number of nodules, nitrogenase activity and colonization of symbiotic bacteria.