The inoculation of red beets with the nitrogenfixing bacteria Pseudomonas putida 23 increased
the activity of the nitrogen fixation in the rhizosphere of the plants grown on meadow soil in the central part
of the Oka River floodplain. The yield of the red beets and the uptake by plants of nitrogen from the soil and
from the 15Nlabeled nitrogen fertilizer applied on the trial microplot increased significantly. A statistically
significant additional fixation of nitrogen from the atmosphere and a positive balance of nitrogen in the soil–
plant system without significant changes in the bulk content of the soil nitrogen after the plant growing were
found in a greenhouse experiment with the application of P. putida. It can be supposed that the excessive
nitrogen determined in this system is related to the incorporation into plants of atmospheric nitrogen fixed in
the rhizosphere of the inoculated plants. The application of P. putida 23 makes it possible to decrease the rates
of NPK fertilizer by two times without losses in the yield of red beets.