Spatial Variability of Manganese Oxide in Two Soilscapes: Upland-Lowland, and Riparian Buffer-Wetland Boundary- Wetland

Background: This research project describes the development of a quantitative measurement methodology to determine the concentration of manganese oxide (MnOx) in two soilscape positions (Upland- Lowland and Riparian Buffer-Wetland Boundary-Wetland). Methods: A reaction between the MnOx in the soil sample and hydrogen peroxide (H2O2) was initiated to determine the level of MnOx reactivity in the soil sample. Data was collected from four sites on Soilscape 1 (Upland, Lowland, and two sites between the Uplands and Lowlands); within each site, five soil profile depths and three sample replicates were measured which comprised a total of 60 samples. Additionally, data was collected from three sites on Soilscape 2 (Riparian Buffer-Wetland Boundary-Wetland), within each site, three soil profile depths and three sample replicates were measured which comprised a total of 27 samples. Measurements were collected and revalidated to assess the accuracy of the measurement protocol. Results: Analysis of data collected from the surface layers in Soilscape 1 indicated that the Lowland (Site 4) had the highest level of MnOx followed by Site 3 with the lowest value occurring at Site 2. A follow up, revalidation study of three of the four sites from the surface layers on Soilscape 1 indicated that the Lowland (Site 4) had the highest level followed by the Midslope (Site 3) with the lowest value occurring at the Upland (Site 1). Therefore, the revalidation study results matched two of the three sites from the initial study. Correspondingly, the data collected from the three sites from the surface layers on Soilscape 2 indicated that the Wetland Boundary had the highest level followed by Riparian Buffer with the lowest value occurring at Wetland. The revalidation study results matched the initial study for each of the three sites from the surface layers on Soilscape 2, which indicated that the Wetland Boundary had the highest level followed by the Riparian Buffer with the lowest value occurring at the Wetland. Conclusion: The results of this study can be used to easily determine the spatial variability o f MnOx levels in soilscapes that range from Upland-Lowland and Riparian Buffer- Wetland Boundary-Wetland, and the movement of soluble MnOx ions within soilscapes by mass flow and/or diffusion processes. In soils with adequate levels of MnOx ions, the use of this methodology can assist in the delineation of the wetland boundary, which has both an economic and land-use importance to society, because of the importance of the ecological functions of wetland ecosystems