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Title: SOIL MICROBIOLOGICAL AND PHYSICOCHEMICAL PROPERTIES 20 YEARS AFTER SURFACE MINE RECLAMATION

Author
item MUMMEY, DANIEL - UNIV. OF WYOMING
item STAHL, PETER - UNIV. OF WYOMING
item Buyer, Jeffrey

Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/2002
Publication Date: 11/1/2002
Citation: MUMMEY, D.L., STAHL, P.D., BUYER, J.S. SOIL MICROBIOLOGICAL AND PHYSICOCHEMICAL PROPERTIES 20 YEARS AFTER SURFACE MINE RECLAMATION. SOIL BIOLOGY AND BIOCHEMISTRY. 34:1717-1725. 2002.

Interpretive Summary: The ultimate goal of surface mine reclamation is to restore the ecological integrity of these disturbed systems. Soil microbial communities are critically important to the ecological functioning of terrestrial ecosystems. The purpose of this study was to examine soil microbial communities in an ecosystem reclaimed after surface mining and an adjacent undisturbed ecosystem thought to be representative of pre-disturbance conditions. At the surface mining site topsoil was removed before mining and stockpiled until mining operations were completed. Stored soil was then spread and seeded with native plant species. In this study, performed twenty years after reclamation, soil lipids were analyzed to determine soil microbial community structure. Soil microbial biomass, soil organic matter, soil inorganic nitrogen, plant canopy coverage, and plant species diversity were also measured. The reclaimed site had, compared to the undisturbed site, lower plant species diversity; lower microbial biomass; lower levels of lipids indicative of biomass, fungi, and bacteria; and lower soil organic matter. Spatial analysis indicated very different patterns in spatial variation between the two sites, with microbes more concentrated around plants in the reclaimed site than in the undisturbed site. These results indicate that ecosystem recovery from surface mining may be extremely slow.

Technical Abstract: Spatial characteristics of soil microbial community structure and selected soil physicochemical factors were analyzed in areas surrounding individual plants of the predominant species in an ecosystem reclaimed after surface mining and an adjacent undisturbed ecosystem in Wyoming. Microbial biomass C and fatty acid methyl ester (FAME) biomarkers for total biomass, bacteria, and fungi were used as indicators of soil microbial community abundance and structure. Reclaimed soil total FAME biomarkers, microbial biomass and soil organic matter (SOM) were significantly less than in undisturbed soils. In contrast to undisturbed soils, FAME biomarkers and microbial biomass C of reclaimed soils exhibited spatial autocorrelation up to 42 cm. Reclaimed soils also exhibited localized enrichment of bacterial, fungal and total microbial biomass indicators, as well as depletion of inorganic N concentrations, around plant bases (less than 10 cm), suggesting relatively poor soil exploration by roots and microorganisms compared to the undisturbed ecosystem. Strong spatial stratification of undisturbed SOM and soil NH4+ pools was found with highest concentrations on the leeward side of shrubs, likely due to localized changes in microclimate and plant litter deposition. This indicates that shrub cover plays a central role in regulating ecological processes and establishment of site heterogeneity, which has important implications for reclamation.