Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2001
Publication Date: N/A
Technical Abstract: Estimating saturated hydraulic conductivity (K) is necessary to model nutrient movement through soil profiles. At a ~2 ha, shallow water table site on Maryland's Coastal Plain, we conducted slug tests in 54 monitoring wells at four different depths (0.8-1.2 m, 1.1-1.6 m, 1.6 to 2.0 m, and 2.0-2.7 m) to obtain a spatial distribution of K. We calculated K values with methods developed by Bouwer and Rice, Dagan, and Butler. Bouwer and Rice and Butler K values were similar, but were consistently less than Dagan K values by a factor of about 0.7. Dagan K values ranged from 0.05 m/d to 19.9 m/d, with an average of 2.0 m/d and a variance of 7.4 m/d. Values for K were typically greater in deeper, coarser textured soil layers than in more shallow, finer textured layers. Conductivities also increased when moving from poorly drained Othello silt loam soils (fine-silty, mixed, mesic, Typic Endoaquult) on the east end of the field to moderately well drained Matapeake silt loam soils (fine-silty, mixed, mesic, Typic Hapludult) on the west end. Limited soil property data were not good predictors of the spatial variability in K values. The best relationship seen was between effective horizontal K values and the depth to redoximoprhic features in the soil. Further collection of field data is necessary to better elucidate relationships between K values and soil properties in an effort to be able to predict K values for water quality modeling.