Effects of Laboratory Warming on Active Soil Organic Matter and Bacterial Diversity During the Long-Term Deсomposition of Forest Litter in Soil Microcosms

To investigate the combined impacts of temperature and plant residues on the mineralization capacity of soil organic matter and taxonomic composition and activity of the soil microbiome, a 364-day experiment with gray forest soil was carried out in a controlled laboratory conditions. Three substrate management, control (C), augmented with aspen leaves (L) and branches (B), and three temperature settings (2, 12, and 22oC) comprised the treatment levels. According to the findings, long-term experimental warming reduced alpha diversity (number of species), increased microbial respiration and decomposition rates, and changed community composition. It has also lowered active soil organic matter. In comparison to branches, the percentage of mineralization in leaves was higher during the course of the year (29.9-57.8% and 20.1-47.6%, respectively). The efficiency of organic matter decomposition rose by 1.5 to 2 times between 2 and 12°C. It has been discovered that all experimental versions are dominated by Proteobacteria. According to α-diversity analysis, leaves were the most preferred substrate for increasing species representation. Temperature was the most significant factor affecting the microbial community’s structure, according to β-diversity data. Our research provides new insights into the soil organic matter formation, and raises interesting questions regarding the microbiological drivers of this process.