Topsoil Stockpiling Versus Exposure to Traffic: A Case Study on In situ Uranium Wellfields

Abstract

Management of soils on areas subjected to planned disturbance, such as surface mine sites, is crucial to post-disturbance restoration. We conducted a study to determine which of the following two topsoil management strategies resulted in less of a negative impact to the soil and vegetation resources and better promoted site restoration on in situ uranium wellfields: (1) removal of topsoil from an entire wellfield and stockpiling until mining activity is complete; or (2) leaving the majority of topsoil on the wellfield and allowing it to be exposed to disturbance associated with wellfield development activity (primarily heavy vehicle traffic). Our study compared selected soil properties from areas on in situ uranium wellfields managed by the two strategies stated above and with adjacent, relatively undisturbed sites. Vegetation reestablishment was assessed on sites where topsoil was left in place. Results indicated that levels of vehicular traffic on wellfields did not cause significant soil compaction and that removal and stockpiling of topsoil results in more negative impacts than disturbance inflicted when topsoil is left in place.

Changes in physical and chemical properties of soil after surface mining and reclamation

“…A low and similar SOC concentration throughout the soil profile of RMS, an observation similar to that by Ganjegunte et al (2009), resulted from drastic soil disturbance caused by surface mining and reclamation activities. These activities result in the depletion of soil organic matter (SOM), increase in oxidation, dilution of C through horizon mixing, acceleration in erosion, and little to no C input from primary production during mining and the initial years of reclamation (Stahl et al, 2002).…”

Redevelopment of Soil Carbon Pools on Reclaimed Surface Mine Lands

“…The moderate disturbance of soil caused by agricultural tillage has resulted in significant losses of SOC in cultivated soils throughout the world. Loss of SOC or SOM has been commonly reported for soils disturbed by activities associated with surface mining (Visser et al, 1984;Harris et al, 1993;Stahl et al, 2002) Reclamation of disturbed and degraded soils generally leads to redevelopment of SOM in the form of plant, microbial and animal residues (Stahl et al, 2003), which greatly contributes to improvement of soil fertility as well as soil structure, water holding capacity, biotic activity, and plant growth (Harris et al, 1996;Lal et al, 1998). Reestablishment of soil carbon pools in disturbed soil also sequesters carbon from the atmosphere where it is contributing to global climate change.…”

Drastic Disturbance of Salt-Affected Soils in a Semi-Arid Cool Desert Shrubland

“…Many arid regions of the world, including the Western United States, have become centers for energy extraction of uranium, coal, natural gas, oil, oil shale, as well as development of wind and solar energy (Copeland et al, 2009). These arid and semi-arid ecosystems can require long periods of time and difficult management strategies for reclamation after disturbance due to removal of stable plant communities (Coffin and Lauenroth, 1996), as well as losses of soil nutrients, structure, and organic matter during disturbance (Mason et al, 2011;Stahl et al, 2002).…”

“…When human infrastructure and disturbance is introduced to these ecosystems, fragmentation and loss of habitat diminish the capacity to support wildlife (Sawyer et al, 2006;Walker et al, 2007), the removal of plant biomass causes losses in soil organic matter and disrupts soil structure (Stahl et al, 2002), fragile soil microbial and fungal associations necessary for nutrient cycling are disrupted (Bates et al, 2010;Belnap, 2002), and soil becomes more vulnerable to colonization by opportunistic, non-native plant species (Bergquist et al, 2007;Bradley and Mustard, 2006;Norton et al, 2007).…”