Soil Microbial Community Recovery in Reclaimed Soils on a Surface Coal Mine Site

Recovery of belowground microbial community structure is important for reclamation success. In this study, the recovery of soil microbial community structure in cool-season grass dominated and sagebrush dominated reclaimed sites were examined using chronosequences ranging in time following reclamation from < 1 to 26 yr. Phospholipid fatty acid (PLFA) analysis was used to characterize changes in microbial community structure with time. Initial effects of surface mining resulted in reductions of total microbial biomass and diversity, with the greatest influence on saprophytic fungi and arbuscular mycorrhizal fungi relative to undisturbed soils. The total concentration of PLFA biomarkers increased after 14 yr in soils established under cool-season grass communities and 5 yr in soils colonized by sagebrush communities. Canonical multivariate analysis of variance indicated that soil microbial communities under reestablished sagebrush were more similar to one another than those under cool-season grasses. In general, microbial biomarkers of reclaimed soils recovered to predisturbance levels within 5 to 14 yr, which indicated that the most important phase of microbial community recovery occurs between 5 and 14 yr after reclamation.