Soil Development in Response to Geomorphic Reclamation in the Semi-Arid West.

Surface mining in the Rocky Mountain west has resulted in drastic land alteration due to mass removal of soil and geologic material. Following mining activities, companies are required by law to reclaim the landscape, however, many mines in operation prior to enactment of the Surface Mining Control and Reclamation Act of 1977 were abandoned. Decade-old reclamation of an abandoned uranium mine in central Wyoming was funded and overseen by the Wyoming Department of Environmental Quality Abandon Mine Lands group, using traditional and innovative geomorphic reclamation techniques. Traditional reclamation involves the construction of long, uniform slopes whereas geomorphic reclamation is designed to incorporate the natural geomorphology and complexity of the landscape. Newly constructed landforms are created using redistributed soil that has become homogenized during mining and reclamation activities. The resulting soil spread 30-cm deep across the reclaimed surface quickly evolves into Entisols. Salvaged topsoil is often finer, more saline and lower in organic matter than the original surface horizon. The loss of the A horizon is the main feature and impediment to successful reclamation. It is hypothesized that pedogenesis has occurred in surface horizons since reclamation was completed as development of thin A horizons through the enrichment of organic matter, weak soil structure and eluviation of salts to lower in the profile. Stratified random sampling techniques were employed within traditional and geomorphic reclamation sites as well as the surrounding native landscapes. Using a combination of field, computer, and laboratory analyses, environmental covariates were documented and soil samples collected and analyzed for a suite of morphological, physical and chemical properties. Results from this research will deliver insight into how human-manipulated topographic differences in reclamation design influence the evolution of homogenized soils. This will ultimately enhance understanding of the succession in soil recovery and ecosystem function after major disturbances.