Asian Journal of Microbiology and Biotechnology

The quantification of microbial biomass is instrumental in evaluating soil degradation and restoration, as it significantly influences nutrient cycling and organic matter turnover, as well as soil structural and functional stability in response to perturbations and management practices. This study aimed to assess the potential effects of microbial biomass, organic carbon, moisture content and basal soil respiration on the establishment of microbial colonies in relation to the fertility of various age series of mine spoil. The chronosequence manganese overburden mine spoils taken in the study are: fresh manganese overburden mine spoil, i.e., 0 yr (MBO0), 2 yr manganese overburden mine spoil (MBO2), 4yrs manganese overburden mine spoil (MBO4), 6 yrs manganese overburden mine spoil (MBO6), 8 yrs manganese overburden mine spoil (MBO8), 10 yrs manganese overburden mine spoil (MBO10). The analysis revealed an increase in microbial biomass carbon, nitrogen and phosphorus (MB-C, MB-N, MB-P), from MBO0 to MBO10. The percentage of organic carbon and moisture content exhibited an increasing trend across overburden spoil, supporting the progressive establishment of microbes. Microbial respiration increased from MBO0 to MBO10; this rise was probably caused by the organic carbon content gradually increasing.  From MBO0 to MBO10, the number of colony-forming units of Azotobacter (AZB), Arthrobacter (ARB), Rhizobium (RHZ), Heterotrophic Aerobes (HAB), Yeast (YST), Actinomycetes (ACT), and Fungus (FUN) increased. The largest population was found in forest soil that helped initiate succession in mine-disturbed areas, while sulfur-reducing bacteria (SRB) showed the opposite trend. Multivariate analysis of variance (MANOVA) shown, HAB pertains highest (99.3%) contribution towards variations among all microbial colonies.