Problematic Calcareous Soils in Western Wyoming.

“Slogs” the mystery of Western Wyoming Matt King & Karen Vaughan Wetlands provide important ecosystem services including water filtration, flood mitigation, C storage, and wildlife habitat among many others. In semi-arid regions of the western United States, wetlands are particularly important due to the low overall areal extent and disparate spatial arrangement resulting in these areas being critical habitat for a diverse suite of animal and plant species. In western Wyoming, seasonally inundated soils formed in calcareous parent material present challenges in terms of wetland identification due to the lack of redoximorphic feature development. While the dominantly white soils display little to no sign of organic matter accumulation, oxidized or reduced Fe and Mn oxides, the landscape maintains wetland hydrology and supports hydrophytic plant communities. To better understand the reason for the lack of visually expressed morphological indicators of reduction in the soil, we employed a mesocosm allowing the selective manipulation of inputs to the soil environment. Intact soil cores were collected from a calcareous wetland by driving the beveled edge of 10-cm diameter PVC tubes into the soil. The mesocosms were extracted from the ground, transported, and individually placed in barrels, inundated with water, and treated with organic C, Fe oxides, a combination of organic C and Fe oxides, or no treatment. Redox potential and pH were measured weekly within each mesocosms and showed steady decline early in the 16-week study period. Results of the morphological and chemical characteristics will be presented pending analyses. We hypothesize the high pH, absence of adequate organic C or Fe oxides, or a combination of these factors is responsible for the lack of visible redoximorphic feature formation. The results of this study will allow us to better understand processes and biogeochemical cycling in these unique western wetland ecosystems. Matt King