Number and ratio of microorganisms in the rhizosphere of spring wheat under the effect of diazotrophy bacterization

Under the agro-ecological conditions of the southern forest-steppe of Western Siberia the influence of Ri- zoagrin biological preparation on microbiological activity of meadow-chernozem soil has been revealed. Studies were conducted in 2011-2013 in the experimental fields of the Department of Seed Growing and in the Microbi- ology laboratory of FSBSI Siberian Research Institute of Agriculture. The effect of biological preparation on 9 varieties of spring soft wheat has been studied. The inoculation of seeds enabled the increase in the number of separate groups of microorganisms in the rhizosphere of the crop. The soil of the experimental field was meadow chernozem medium-humic moderately heavy loam soil. On average over the study years, the number of bacteria on the plain agar was the largest one on Pamyati Azieva variety, the number of microorganisms on starch- ammonia agar was the largest one on Omskaya 35 variety, the number of nitrifying microorganisms on Duet variety. The number of oligonitrophilic and the total number of microorganisms was largest in the rhizosphere of Pamyati Azieva and Omskaya 35 varieties. Inoculation increased the abundance of fungi in the rhizosphere of Duet and Pamyati Azieva varieties. It has been found that the ratio of the individual groups of microorganisms varied depending on both growing conditions, genotype and the actions of Rizoagrin. So, for Pamyati Azieva variety by grain ripening the percentage of bacteria on MPA increased in average for the years of study by%. For Duet variety in both phases of development the percentage of microorganisms on starch-ammonia agar increased by 3.94, 4.72 %, and Omskaya 35 variety showed an increase in the percentage of oligonitrophilic microorganisms by 6.29 % in the phase of earing and by 2.82 % in the period of grain filling. Close direct and inverse dependences between microorganisms in the rhizosphere of the crop, main nutrients, soil moisture and hydrothermal conditions have been revealed.