Comparative analysis of species composition of micromycetes of chestnut soil and leached chernozem soil

Relevance . The article deals with the determination of the species and quantitative composition of soil micromycetes of moderately deep chestnut soil and leached chernozem soil, as well as the ecological plasticity of the identified microscopic fungi. Methods . The objects of the study were microscopic fungi contained in different types of fallow soil in the regions of the Southern Federal District — chestnut shallow soil and leached chernozem. The study of soil samples under laboratory conditions for the presence of micromycetes was carried out according to generally accepted methods. The third dilution (1:1000) was used for sowing the soil suspension on Czapek medium. Results . In 2023–2024, the species composition of micromycetes was more diverse in chestnut soil (9 genera) samples compared to leached chernozem soil (6 genera). Micromycetes common to chestnut and leached chernozem soils were identified: Cladosporium spp ., Fusarium spp ., Penicillium spp ., Aspergillus spp . and Mucor spp . The presence of these micromycetes genera in soil types that differ in structure and microelement content indicates their ecological flexibility and developed ability to adapt to different moisture conditions and soil types. Fungi Trichoderma spp . were not found in chestnut soil samples, and fungi Acremonium spp ., Mortierella spp . and fungi-like organisms of the genus Pythium spp . were not found in leached chernozem samples, which allows us to classify them as stenobionts. The dominants of the second rank in the chestnut soil were Penicillium spp . with an abundance index of 37%, in the leached chernozem — Fusarium spp . and Trichoderma spp . (the abundance was 45 and 36%). The highest spatial frequency of occurrence of soil micromycetes in the conditions of the Kotelnikovsky district was noted in the genus Penicillium spp . (83%), in the conditions of the Oktyabrsky farm — in Trichoderma spp . and Fusarium spp . (100% each).