The experiments were carried out in 2018–2021   on ordinary chernozem in the conditions of the Rostov region. The winter barley variety Master was cultivated. The predecessor is corn for grain. Mineral fertilizers included ammonium nitrate (34.4%), ammophos (12-52), nitroammophos (16-16-16). Nitrogen-phosphorus fertilizers (a fertilizer mixture of ammonium nitrate and ammophos) and nitroammophoska (16-16-16) were applied when sowing barley, ammonium nitrate was applied by a surface method randomly in the spring tillering phase. Bacterial preparations contain strains of associative nitrogen-fixing microorganisms: Mizorin, Rizoagrin, Extrasol. They were applied to barley seeds in the pre-sowing period. It has been established that the use of the bacterial preparation Mizorin (600 g/ha) against the background of pre-sowing application of nitrogen-phosphorus fertilizer at a dose of N30P30, nitrogen top dressing with ammonium nitrate at a dose of 30 kg/a.i. ha increased the increase in grain yield on average over three years compared with the control variant (without the use of agrochemicals) by 0.71 t/ha, or 14.4%. The application of the biological preparation Mizorin without mineral fertilizers increased the yield by 0.31 t/ha, or 6.3%, compared to the control variant. In 2019–2021, the average protein content in the grain of winter barley in the control variant was 10.7%, which ensured the collection of protein 525 kg/ha. Against the background of nitrogen-phosphorus fertilizers at a dose of N30P30 and nitrogen supplementation at a dose of 30 kg/ha, the maximum increase in protein content was in the variant using Mizorin, which was 1.1% compared to the control variant, while the protein yield in the crop increased by 138 kg/ha, or by 26.3%.