Soybean plants belong to the Leguminaceae family and are of a huge importance worldwide, as a source of different kinds of products, used in various industries, including food, medicine and energy. To produce organic matter soybean plants take up essential mineral macro- and microelements from soil and atmosphere. Nitrogen (N) which represents one of the most important essential macro element required throughout plant development is absorb by roots from soil as ions of nitrate (NO3−) or ammonium (NH4+). Also soybean plants, like other leguminous crops, are capable to satisfy a considerable part of their demands in N by fixation of atmospheric N2 in symbiosis with bacteria Bradyrhizobium sp.. Bacteria colonize plant roots, penetrate inside of root cells and are transformed into symbiotic forms – bacteroids, which are localized in the new root morphological structures – nodules. The process of N2 fixation by bacteroids of the root nodules is catalyzed by the enzyme nitrogenase (NG), which is influenced by diverse endogenous and exogenous circumstances, including type and quantity of the essential nutrients. In this study, we have attempted a comparison of nodule growth and NG activity of inoculated soybean plants supplied with low concentrations of mineral N, and also with essential metal ions compounds, inclusive Mo, Co, Mn and Zn. The effect of NH4NO3, NH4 (SO4)2 and NaNO3 supply on plant growth, nodulation and NG activity was investigated in a greenhouse experiment with the use of sand culture and the nutrient media after Preanicinikov, using (1/30 part) of the mineral N. The highest values of nodule NG activity were in the variant with NH4 (SO4)2, followed by NaNO3.The nodule biomass and NG activity of the soybean plants that grew on the medium with NH4NO3 was at the lowest level. It has also been shown that the growth of soybean nodules and NG activity related to micronutrient supply, administered at the stage of the first trifoliate leaf, has varied and were determined by the metal ion type and the plant ontogenesis stage. By the stimulatory effect on NG activity, metal ions can be arranged in the following descending order: i) at the beginning of the bloom: Mo> Co > Mn> Zn; ii) at the mass flowering: Co >Mn > Mo >Zn; and at the pods formation: Co >Mn >Zn> Mo. The highest level of NG activity for all tested metal ions was observed at the mass flowering of soybean.