Investigating Problematic Hydric Soils using Hydrology, IRIS Tubes, Chemistry, and the Hydric Soils Technical Standard

摘要

Resource professionals rely on soil morphology to make determinations of hydric soil status. Characteristic morphologies led to the development of field indicators for hydric soil identification and delineation. This study examined soils not meeting approved field indicators. These included high-chroma sandy soils, dark sandy soils, and marl soils located in Michigan. All soils displayed high water tables within 25 cm (10 in) of the surface for a minimum of 14 consecutive days. Indicator of reduction in soils (IRIS) tube data confirmed reducing conditions in wetland sites, with average Fe removal of 74%; only 4.8% removal was observed in uplands. Ten of 11 soils examined met the hydric soil technical standard (HSTS). Results indicate that two additional field indicators (S7-Dark surface and F10-Marl) should be approved in the region. Soil chemical data examined the development of hydric soil morphologies. Laboratory incubations monitored the formation of low-chroma colors with artificial C substrate in high-chroma sands. This work expands the range of accepted field indicators and provides a case study for applying the HSTS to problematic soil situations.