Soil Morphology as an Indicator of Soil Hydrology on a Hillslope Underlain by a Fragipan
- M. A. Calmon,
- R. L. Day,
- E. J. Ciolkosz and
- G. W. Petersen
In Pennsylvania the presence of redoximorphic features is often used to evaluate the suitability of soils for on-site waste disposal. Many studies have related soil morphology to soil saturation; however, few studies have addressed fragipan soils and perched water table systems. The objective of this study was to determine the relationship between water table dynamics and soil morphology on a hillslope underlain by a fragipan. Five landscape positions along a mixed grass and forest-covered hillslope with eolian- and glacial till-derived soils were chosen for the study. Each landscape position was instrumented with: (i) a continuous water table monitoring well and two 5-cm-diam. Polyvinyl chloride (PVC) observation wells; (ii) triplicate thermocouples at 25- and 50-cm depths; (iii) five platinum electrodes at 25- and 50-cm depths; and (iv) one zero-tension soil solution sampler at 25- and 50-cm depths. Although the water table was close to the soil surface at all five landscape positions during the wet seasons (fall and winter) of 1996, redoximorphic features were never observed within 19 cm of the soil surface. Redoximorphic features were found at depths ranging from 19 to 40 cm. At the minimum depth to redoximorphic features the soils were saturated 28 to 39% of the monitoring period. Low soil temperature, short-duration of saturation events (<10 d), and lack of organic C appear to be the main factors preventing the reduction of Fe and redoximorphic feature formation when the water table was present. Continuous monitoring of the water table is needed to accurately quantify the hydrodynamics of these systems for some land-use decisions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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