Biological activity of rhisosphere of grain forage crops in case of application of bacterial products
The studies were carried out in field experiments of Federal State Budgetary Scientific Institution "Omsk Agrarian Research Center" in the southern forest-steppe of Western Siberia. The aim of the research is to study the effect of application of biological products of associative diazotrophs on biological properties of the rhizosphere of grain forage crops of varieties of Omsk selection. The tests were carried out on varieties of spring barley for grain forage and brewing purposes bred at Omsk agrarian scientific centre (FSBSI "SibSRIA"): Omsky 95, Sasha, Omsky hulless 1, Omsky 90, Omsky 91, Omsky 101 and oats for cereal purposes - Siberian Hercules. Preparations of complex action produced at All-Russian Research Institute of Agricultural Microbiology (FSBSI All-Russian Research Institute of Agricultural Microbiology:, St. Petersburg, Pushkin) Rizoagrin (Agrobacterium radiobacter), Azorizin (Azospirillum), Mizorin (Arthrobacter mysorens), Flavobacterin (Flavobacterium) were used for inoculation of seeds. The soil of the experimental plot is meadow-black soil, medium-thick, medium-humus, heavy loamy with a humus content of 6.5%, water pH - 6.5. It was found that the microflora population of the rhizosphere of agricultural crops reacted dubiously to application of biological products and depended on genotypic characteristics of the varieties. The greatest positive effect of seed inoculation on the total number of microorganisms was noted in the rhizosphere of barley variety Omsky 95, the increase was 35% when the seeds were treated with Azorizin, with Rizoagrin -70% in relation to the control. The inoculation of oat seeds of Siberian Hercules variety with the bioproduct Flavobacterin contributed to an increase of the total number of microorganisms in the rhizosphere up to 27% compared to the control. The processes of nitrogen immobilization (K<sub>immob></sub>1) prevailed in the soil under crops of grain forage crops in the years of the research. The highest coefficient of organic matter (potentially mineralizing) transformation was noted in the rhizosphere of grain-forage barley Omsk hulless 1 when seeds were treated with Rizoagrin -148 units (109 units in the control) and in the rhizosphere of cereal oat Siberian Hercules when seeds were treated with Mizorin - 91.5 units . (55.8 units in the control).