The Structure of Bacterial and Fungal Communities in the Rhizosphere and Root-Free Loci of Gray Forest Soil

Abstract

The taxonomic composition, abundance, and diversity of bacterial and fungal communities in the rhizosphere loci and bulk mass of the gray forest soil (Eutric Retisol (Loamic, Aric, Cutanic, Humic)) under potatoes, maize, and white mustard grown with the application of mineral and organic fertilizers were compared. Among bacteria, Bacillus megaterium and Paenibacillus polymyxa species predominated in all the experimental variants. The micromycete community was represented by 39 species belonging to 19 genera. Under the impact of organic fertilizers, the abundance of Trichoderma harzianum—an antagonist of many phytopathogens—increased. A decrease in the abundance of representatives of Fusarium genus was observed both in the rhizosphere and in the bulk soil. Fertilization was the most significant factor determining the structure and diversity of micromycete communities both in the soil and rhizosphere. The application of mineral fertilizers reduced the diversity of micromycetes in soil, whereas the use of organic fertilizers increased it. In general, organic fertilizers proved to be more favorable for the rhizosphere and bulk soil mycobiomes and for the total soil suppressiveness than the mineral fertilizers.