Tuesday, 8 November 2005
7

Evaluation of Saturated Hydraulic Conductivity for Soils in the Southern Piedmont in Georgia.

Maria E. Abreu, University of Georgia, 3111 Miller Plant Sciences Bldg., Athens, GA 30602

For common soils in the Southern Piedmont, clayey upper Bt horizons have been estimated to have the lowest Ks in the profile, and deeper more loamy horizons to have higher Ks. Limited data suggest that these clayey horizons are more permeable than deeper horizons, however, primarily due to better-expressed structure. Thus, the objective of this study was to evaluate Ks for major horizons of soils on various landscape positions in Piedmont landscapes. On five hillslopes in the Georgia Piedmont, Ks was measured at 21 sites with a constant head permeameter for the upper Bt, middle to lower Bt, and BC horizons, along three transects extending from summit to footslope landscape positions. Three representative pedons on each hillslope that represented a range in Ks were described and sampled for laboratory characterization including water characteristic curves and micromorphological analysis. Upper Bt horizons had highest clay contents and clay was substantially lower in BC horizons. Mean Ks over all hillslopes and locations was 42, 2, and 18 cm d-1 for upper Bt, middle Bt, and BC horizons, respectively. Analysis indicated that there was no spatial correlation between Ks and landscape position for any of the three depths. Differences in Ks among depths across the hillslopes were significant and related to a combination of horizon texture and pedogenic structure including weak platy structure in BC horizons.

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