Krasnoyarsk forest-steppe trial fields agrochernozem microbiological indicators assessment

The purpose of the study is to assess the structure of microbial communities in agrochernozems of the Krasnoyarsk forest-steppe on the experimental fields of the Minderlinskoye farm of the Krasnoyarsk GAU and the Minino field station of the Krasnoyarsk Research Institute of Agriculture, KSC SB RAS. The study of soil microflora was carried out during the growing season of 2020. Analysis of microbiological parameters of soil samples was conducted by conventional methods. The quantitative indicators of ecological and trophic groups of microorganisms were assessed: copiotrophs – on mesopatamia agar, prototrophs – on starch-ammonia agar, oligotrophs – on soil agar, nitrogen fixers and oligonitrophils – on Ashby agar. The coefficients of mineralization and oligotrophy were calculated. The number of soil micromycetes was determined on potato-dextrose agar. Sowing of soil suspensions was carried out in triplicate from dilutions up to 106. Identification of micromycetes was performed on the basis of morphological characteristics. Pure cultures of dominant bacteria were identified by time-of-flight mass spectrometry using a MALDI-TOF MS Microflex mass spectrometer. The high values of the coefficients of mineralization and oligotrophy for the soils of the Minderlinskoe experimental farm were established – 1.85±0.05 and 0.94±0.02 and low values for the soils of the Minin station – 2.30±0.01 and 0.82±0.03 respectively. The species of bacteria that dominate during the field season in areas with different agrochemical soil characteristics have been isolated and identified. Differences in the taxonomic composition of microbial communities in the study areas were established: species of the genus Bacillus (B. simplex, B. marisflavi, and B. pumilus) prevailed in the soils of the Minderlinskoye experimental farm, while in the soils of the Minino field station Pseudomonas mandelii, Bacillus safensis, Rhoropoldococc Arthrobacter polychromogenes and Arthrobacter parietis dominated. The presence in microbial populations of species previously described as destructors of polyaromatic hydrocarbons, polyhydroxyalkanoates, and other organic compounds indicates a high degradation potential of agrogenic soils. Species of the genus Penicillium dominated among the micromycete population in all soil samples during the field season. It has been shown that the soils of the Minderlinskoye experimental farm have a high level of suppression due to the large population of fungi of the genus Trichoderma, which inhibits the development of phytopathogenic micromycetes Alternaria and Fusarium.