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Soil‐Landscape Relationships in Virginia: II. Reconstruction Analysis and Soil Genesis
Author(s) -
Stolt M. H.,
Baker J. C.,
Simpson T. W.
Publication year - 1993
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1993.03615995005700020023x
Subject(s) - weathering , pedogenesis , silt , soil water , geology , soil science , leaching (pedology) , entisol , soil horizon , soil production function , paleosol , transect , parent material , soil morphology , geochemistry , soil type , geomorphology , loess , oceanography
Reconstruction analysis is a means of quantitatively determining gains and losses of soil constituents as a result of pedogenesis. Soil reconstruction techniques were employed to examine the relationships between landscape position and soil genesis in the Piedmont and Blue Ridge Highlands regions of Virginia. Backslope soils occurring on slopes of up to 18% have profile morphologies and clay distributions very similar to associated summit soils. Footslope soils are bisequal, have less clay in the Bt horizons, and show less profile development than associated summit or backslope soils. Transects across toposequences indicated minimal differences in profile morphology between summits and lower backslopes. The major processes that could be quantified using reconstruction analysis were sand and silt weathering, subsequent weathering product transport and leaching, clay illuviation, and accumulation of free Fe oxides. Soil reconstruction indicated that summit and backslope soils undergo the same soil‐forming processes. Footslope soil formation is, in part, dependent on the type and composition of parent material. Footslope horizons formed in substantially weathered local alluvium showed minimal sand and silt weathering and associated leaching of weathering products. Underlying horizons formed from parent rock showed evidence of both weathering and clay illuviation. Losses of elemental Fe, K, and Ti were found to coincide with weathering of silt and sand. Losses and gains of dithionite‐citrate‐bicarbonate (DCB) extractable Fe and Al were associated with gains or losses of clay‐sized material.