Soil of the Blue Ridge

The dominant soil order in the Blue Ridge Province is the Inceptisol. This order consists of relatively young soils that lack horizons of accumulated illuvial clay (argillic horizons). Most have weak to moderate profile differentiation. The chief Inceptisol Great Groups in the Blue Ridge are Dystrochrepts and Haplumbrepts. Ultisols, particularly Hapludults, do occur in the Blue Ridge. Sizeable areas of this Province are also mapped simply as Rockland (Buol 1973). In the high Great Smoky Mountains, soils on the steeper slopes most typically are Umbric and Typic Dystrochrepts. At the highest elevations and on gentler slopes, Haplumbrepts and Spodosols have developed on suitable parent materials (Springer and Elder 1980). Dystrochrepts and Hapludults are the most common soils on the midslopes of the Smoky Mountains and in the Foothills to the northwest. Paleudults and Hapludults are the main soils formed on alluvial, colluvial, and residual parent materials in the carbonate-floored coves of the Southern Blue Ridge (Clark and Others 1989).

In the Blue Ridge of North Carolina, Graham and Buol (1990) reported that 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 where fresh mica gneiss or schist is being eroded tend to be in the micaceous mineralogy class, whereas those in highly weathered colluvium and in very stable residuum (nearly level summit positions) have been depleted or mica and are in the oxidic class. The authors proposed a conceptual model relating soil development on slopes to a process, in which colluvial transport interrupts the orderly progression of residual soil development.

In the Northern Blue Ridge, as exemplified by Shenandoah National Park, Hapludalfs, Eutrochrepts, and Hapludults are typical upland soils. Along Skyline Drive, theyform in parent materials derived from the Catoctin Formation, which is composed of greenstone, a metamorphosed basalt (Clark and others 1989).