Soil–Microbial Biomass Ecological Stoichiometric Characteristics of Coal Mining Reclamation Areas Are Driven by Reclamation Chronosequences

ABSTRACT Mine reclamation is essential for promoting soil development and ecological renewal in mining areas. However, changes in the biological stoichiometry of soil microbes, entropy effects and stoichiometric imbalances over increasing reclamation years remain unclear. This study aimed to clarify the responses of soil–microbial carbon (C), nitrogen (N) and phosphorus (P) stoichiometry to reclamation chronosequences, and to evaluate their links with microbial quotient indices, stoichiometric imbalances and microbial entropy ( q MB). Accordingly, this study investigated the dynamics of soil–microbial C, N and P within 0–40 cm soil profiles across four reclamation chronosequences (4a, 8a, 12a, 14a) in mining areas. The results showed the following. (1) The reclamation chronosequence had a significant effect on soil–microbial C, N, P and stoichiometric ratios. As the reclamation chronosequence increased, there were overall increasing trends in C soil , N soil , C mic , N mic , P mic , C soil :P soil , C soil :N soil , N soil :P soil and C mic :N mic , while P soil , N mic :P mic and C mic :P mic showed decreasing trends. (2) As the reclamation chronosequence increased, q MBP, q MBN, C imb :P imb , C imb :N imb and N imb :P imb generally increased, while q MBC showed a decreasing trend. As the soil layer deepened, C soil , N soil , P soil , C mic , N mic , P mic , C soil :P soil , C soil :N soil , C mic :N mic , C imb :P imb , C imb :N imb and N imb :P imb all tended to decrease, while q MBC, q MBN and q MBP generally increased. (3) Redundancy analysis (RDA) results showed that C imb :P imb , Cimb:N imb , N mic :P mic and C soil :N soil were the primary factors influencing changes in q MB over different years following mine reclamation. In conclusion, soil microbial biomass C, N and P, and stoichiometric ratios, as well as stoichiometric imbalances in the coal mining reclamation area, were driven by reclamation chronosequences, which in turn positively or negatively influenced q MB. These factors play a crucial role in coal mining reclamation areas and have positive implications for the recovery of soil microbial resources in the region.