This study explores the seasonal variability of microorganisms in the mountain-brown soils of the Gobustan region of Azerbaijan and how this variability depends on soil-climatic conditions. As part of the research, soil samples were collected across all four seasons- spring, summer, autumn, and winter and microbial abundance was quantified using standard serial dilution and plate count techniques. The results showed that bacterial populations reached their peak during the early vegetation period (autumn), when soil temperature was moderate and moisture levels were optimal. In contrast, fungal colonies were more active in spring and summer, which is attributed to their differing responses to temperature conditions. Microorganisms are considered key indicators of soil biological activity, playing essential roles in nutrient cycling, nitrogen fixation, soil organic matter (SOM) formation, and element mobilization. Their diversity and abundance are directly linked to soil health and productivity. Microbiological diagnostics are crucial for evaluating the ecological status and fertility potential of soils, especially under semi-arid conditions. Seasonal monitoring of microbial indicators allows researchers to assess how environmental factors influence biological processes and the adaptive capacity of soil ecosystems. Most soil microbiota are concentrated in the upper 25–30 cm of the soil profile, where biological fractions occupy less than 1% of the total volume. Despite their small proportion, microorganisms respond rapidly to environmental changes and serve as sensitive indicators of soil conditions. Their ability to adapt and dominate under new conditions reflects shifts in soil health and ecological balance.
