Soil-Geomorphic Relations on the Blue Ridge Front: II. Soil Characteristics and Pedogenesis
- R. C. Graham * and
- S. W. Buol
Soils along two mountain slope transects in mica gneiss and schist terrane were studied to better understand soil distribution and genesis on the Blue Ridge Front landscape in North Carolina. Soils may form entirely in residuum or colluvium, but on most slope positions they have developed in both materials. The colluvial/residual nature of soils is related to geomorphic position and has a strong influence on soil properties and the evolution of the soils. Soils on upper slopes have a significant residual component as a result of weathering into the parent rock. Low slope positions are sites of accumulation, resulting in deep soils formed in colluvium. Dystrochrepts, or very weakly expressed Hapludults, have developed entirely in colluvium, whereas soils with at least a partial component of residuum are Hapludults. Soils on landscape positions down wearing into fresh mica gneiss or schist are in the micaceous mineralogy class, whereas those in highly weathered colluvium and in very stable residuum (i.e., nearly level summit positions) have been depleted of mica and are in the oxidic class. A conceptual model relating slope processes to pedogenesis is proposed in which colluvial transport interrupts the orderly in situ progression of residual soil development. The genesis and distribution of soils are best understood when studied in landscape contexts, rather than at the level of individual pedons or classification units.
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