Wetland hydrology; Soil moisture
The duration and depth of seasonal soil saturation affects soil suitability for many landuses and are critical factors in the determination of hydric soil boundaries for jurisdictional wetland delineations. Biochemical processes in saturated, anaerobic soil conditions lead to the genesis of soil morphological features that indicate the duration of seasonal saturation. However, few prior studies confirm the relationships between soil hydrology and soil morphology in Minnesota landscapes. We monitored water table and piezometric elevations, soil temperature, redox potential, and soil matric potential at multiple depths for five locations along a hillslope hydrosequence of well to very poorly drained prairie soils (Mollisols) in southeastern Minnesota. Sites were monitored at two-week intervals for two years. Detailed soil profiles were described and sampled during the summer of 1992 along this hydrosequence. The duration that water tables were within the upper 30 cm of the soil ranged from 0 weeks at the shoulder to 10 weeks at the toeslope and 30 weeks in the drainageway. Low(< 300 mV) soil redox potentials, dark A horizon colors (chroma~ 1), low chroma subsoil matrix colors (chroma ~ 2), and organic carbon contents > 3% were observed for the toeslope and drainageway soils subjected to extended periods of high water tables. An increase in abundance of soil morphological features associated with depletions and/or concentrations of Fe and Mn on mineral soil grains was also associated with periods of prolonged soil wetness. Preliminary results suggest lateral movement of water through the soils above a layer of dense till linking the hydrology of upland and wetland soils.
Bell, J. C.,
Thompson, J. A.,
Butler, C. A.
Morphological Indicators of Seasonally-Saturated Soils for a Hydrosequence in Southeastern Minnesota.
Journal of the Minnesota Academy of Science, Vol. 59 No.4, 25-34.
Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol59/iss4/5