Characterizing Minimally Disturbed Soils in a Highly Disturbed Urban Environment

Abstract

Core Ideas Historical maps were used to identify two undisturbed soil pedons in the urban area. Strong correlation was found between dolomite and the very coarse and coarse sand fractions. The Y2O3/ZrO2 ratios of soil minerals can be used to identify disturbance boundaries. Urban soils are often highly disturbed by anthropogenic activity, and consequent impacts on soil function are not well understood. Minimizing the disturbance of highly modified soils, including those at The Ohio State University, will decrease local C footprints. The main objective of this study was to locate and characterize relatively undisturbed soils in the urban study area to use as a baseline for comparison with a wider range of sampled profiles. Historical campus maps were used to locate and sample three areas where building footprints indicated that minimally disturbed soils might be found. Pedon 1 was classified as a Celina silt loam (fine, mixed, active, mesic Aquic Hapludalfs) and Pedon 2 as an Eldean silt loam (fine, mixed, superactive, mesic Typic Hapludalfs). Pedon 3 exhibited evidence of significant disturbance due to the presence of foreign materials and disrupted horizonation. Pedon 3 had the highest percentage of total C of all three sites at 0‐ to 70‐cm depth due to the presence of asphalt. In Pedon 2, most of the total C from the BC horizon and below was inorganic C derived from calcareous glacial outwash parent material. Pedon 1 showed a mostly homogeneous parent material due to the consistent geochemical ratios throughout the soil profile. There were abrupt horizon discontinuities in Pedon's 2 and 3 ratios indicating heterogeneity of materials. Establishing baseline soil characteristics shows how urban soils have been modified over time and provides information for policymakers to understand the urbanization of soil environments and to enhance ecosystem services.