Objective. Investigate the possibility of enriching mineral fertilizers (Azofoska: NPK 16:16:16) with agronomically useful microorganisms by applying their suspensions to solid fertilizer granules. Methods. Microbiological (cultivation of microorganisms on different media, obtaining suspensions, determination of titre in suspensions, microscopy), field small-plot experiment in six repetitions (growing potatoes on sod-podzolic soil), full accounting of the harvest from each plot, statistical. Results. Enrichment of Azofoska with microorganisms by applying aqueous suspensions of Trichoderma harzianum PD3 and representatives of the genus Bacillus to fertilizer granules before their application to sod-podzolic soil at the rate of N80P80K80 had different effects on the yield of Bellaroza potatoes. T. harzianum PD3- and Bacillus sp. 102-enriched fertilizers contributed to a reliable increase in crop yield in a three-year experiment. The combination of these microorganisms to enrich Azofoska did not provide a stable effect over the years of research. The use of B. vallismortis 44- and B. cereus SB1-enriched fertilizers was not effective. The greatest increase in potato yield was ensured by the use of Bacillus sp. 102-enriched fertilizers. At the same time, minor deviations from the average parameter were reported for all six repetitions in the experiments (in contrast to other variants). Conclusion. The fundamental possibility of increasing the efficiency of mineral fertilizers by enriching them with agronomically useful microorganisms when growing potatoes on sod-podzolic soil has been shown. The efficiency of biologically modified Azofoska depended on the microorganism used for enrichment. Additional research both on the screening of microorganism strains promising for this purpose, as well as technological aspects (the number of cells of microorganisms on fertilizer granules, the use of adhesives, carbon sources and adjuvants during fertilizer enrichment, the terms of preservation of microorganisms on granules depending on the conditions of enrichment, extension of the spectrum of fertilizer types and types of agricultural crops, etc.) is necessary.
