Features of changes in the number and composition of the microbiome of the rhizosphere of winter wheat in the process of ontogeny

Abstract

In agroecosystems, microorganisms are the main factor in the soil formation process, plant nutrition and phytosanitary condition of the soil. All measures aimed at restoring soil fertility and increasing productivity, environmental safety of agricultural production, are closely related to the activity of microorganisms. Increased local activity, biomass and diversity of microbiota are one of the most important characteristics that distinguish the rhizosphere from the total soil volume. The purpose of the research was to study the number and composition of the microbial complex of the rhizosphere of grain crops (winter wheat of different varieties of domestic selection) in the process of ontogenesis. To conduct a set of microbiological studies, soil samples (typical chernozem) were selected and prepared in compliance with standard requirements for sample preparation and storage in laboratory conditions. Analysis of rhizosphere soil samples was carried out on variants of different varieties of winter wheat of domestic selection. The number of soil microorganisms was determined by seeding suspensions on nutrient media according to generally accepted methods in microbiology. The determination of the total microbial biomass in the soil was carried out by the rehydration method, and the intensity of soil “breathing”, in terms of CO2 release and O2 absorption, was determined by the manometric method (Warburg apparatus). It was found that winter wheat varieties affected the formation of the microbiome of typical chernozem. The number and composition of the microbial complex of the rhizosphere of winter wheat in the process of ontogenesis changes significantly, especially in terms of the ratio of the number of spore-forming and non-spore forms of microorganisms under the same conditions of agricultural technology for growing crops. The rhizosphere's total pool of saprotrophic microorganisms shows biomass variability and changes in favour of ecoplastic bacilli. An increase in the number of spore-forming bacteria to 4.2 x 107 CFU/g was found in the variants of cultivation of certain varieties. Cultivation of different varieties of winter wheat demonstrates stable indicators of CO2 emission intensity – from 5.2 to 7.0. A similar trend can be traced in the absorption rate of O2 (no more than 5.3-6.8)