Efficiency of application of mineral fertilizers and bacterial preparations on winter barley in the conditions of the Lower Don

Field experiments on ordinary black soil were conducted in 2018-2021 in the Rostov region. The object of research was a variety of winter barley Master. The predecessor is corn for grain. Bacte-rial preparations developed at the All-Russian Institute of Agricultural Microbiology (VNIISHM) in St. Petersburg contain strains of associative microorganisms-nitrogen fixators: Mizorin, Ri-zoagrin, Extrasol. They were applied to barley seeds in the pre-sowing period. It was found that the use of Mizorin (600 g /ha) for seed treatment before sowing against the background of a near-sowing application of nitrogen-phosphorus fertilizer in the form of a mixture of ammophos and ammonium nitrate at a dose of N30P30, nitrogen fertilization by a scattered surface method with ammonium nitrate at a dose of 30 kg/ ha of the active substance increased the increase in grain yield on average for 3 years compared with the control variant by 0.71 t/ ha or by 14.4%. The use of the biological preparation Mizorin without mineral fertilizers against the background of natural soil fertility increased the yield compared to the control variant by 0.31 t /ha or by 6.3%. On av-erage, in 2019-2021, the protein content in winter barley grain in the control variant was 10.7%, which provided a protein harvest equal to 528 kg/ha. Against the background of nitrogen-phosphorus fertilizers at a dose of N30P30 and nitrogen fertilizing at a dose of 30 kg / ha, the max-imum increase in protein content was obtained in the variant with the use of Mizorin, which compared to the control variant was 1.1%, while the protein harvest increased by 138 kg/ha or 26.1%. Keywords: WINTER BARLEY, ORDINARY BLACK SOIL, BACTERIAL PREPARATIONS, MINERAL FERTILIZERS