Heterogeneity of Hydromorphic Features: Observations from a Coastal Plain Hydrosequence
- S. A. Tangren,
- D. S. Fanning,
- K. L. Prestegaard and
- M. C. Rabenhorst
An understanding of soil spatial heterogeneity is prerequisite to any analysis of systematic catenary variation. In this chapter we discuss: (i) the variability that results from choice of a sampling site within a pedon, (ii) how that variability affects our ability to detect catenary variation, (iii) within-pedon heterogeneity as a function of catenary position, and (iv) the implications of within-pedon heterogeneity for soil classification. The study site is a valley situated on glauconite-containing, sandy-loams of the Coastal Plain in Anne Arundel County, Maryland. Six of forty pre-existing well sites were selected for replicate soil sampling. The well sites represent a variety of soil drainage conditions, from moderately well to poorly drained. Within a pedon-sized (10-m2) area around each of the six wells, six replicate auger holes have been drilled and the profiles described (36 descriptions total). For each description, the depth to redox concentrations and redox depletions was recorded. Standard errors of the six replicated descriptions were calculated and provide a quantitative indication of each pedon's redoximorphic variability. Upland pedons were found to have greater redoximorphic variability than wetland pedons. Variability within a pedon often affected the conclusions we made about the soil. Although considerable, particularly in higher positions of the transect, variability was not so great as to obscure the landscape trend in depth to redoximorphic features. The spatial heterogeneity of hydromorphic features affected our determinations of soil drainage class, hydric soil indicators, and taxonomic classification.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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