A Pedological Investigation of Soils of the Cumberland Plateau of Tennessee

Soil formation depends on the unique interactions of influential soil forming factors. Soil parent material determines many of the properties exhibited by soil formed within that parent material. The Cumberland Plateau of Tennessee is a broad, uplifted, level-bedded, block of Mississippian and Pennsylvanian age stratigraphy located from 83^o40'00" W to 85^o05'00" W latitude along the Kentucky border and 85^o20'00" W to 86^o15'00" W along the Alabama border. The Pennsylvanian stratigraphy is composed mainly of sandstone with some interbedded beds of shale. The geology of the Plateau is in many locations overlain by a deposit of silt-laden, eolian loess likely deposited in the early Holocene (~10,000-12,000 years ago) shortly after the last glacial maximum. Certain landforms such as ridge tops were conducive to loess deposition while side slope positions did not facilitate deposition. As a result, soils present on the Cumberland Plateau exhibit properties that reflect the inherent differences related to soil parent material.

The objective of this study was to examine the effects of soil parent material and slope on soil genesis and morphology. An analysis of inherent soil properties will support determinations of soil parent material type and the degree of pedogenic alteration that has occurred within that soil parent material. Sites selected for this study have soils that represent the varied landform types present on the Plateau and the differing soils formed on those landforms. In areas that allowed for loess deposition soils exhibit a parent material sequence of loess over sandstone residuum while soils on side slopes formed from residuum. Pedons sampled from sites located on the Plateau Agricultural Experiment Station and Grassland Unit of the University of Tennessee were described and characterized through both field and laboratory investigation according to National Cooperative Soil Survey guidelines. Particle size analysis data proved useful in the examination and determination of soil parent material source. In pedons that exhibited a discontinuity a particle size analysis on a clay free basis was used to examine differences in soil parent material that would perhaps be masked by pedogenic alteration of clay minerals.

The study pedons exhibit properties that seem primarily dependent on the influence of soil parent material and soil slope. Soils in upland areas that form from transported loess over residual sandstone contain fragic properties at the interface of the two contrasting parent materials. These soils are classified as Typic Fragiudults and Typic Hapludults based their individual morphology. Soils formed on side slopes do not contain loess. The sandstone on which these soils form is highly resistant to weathering and pedogenic alteration. As a result, soils formed on steeper slopes do not exhibit a high degree of pedogenesis. These soils are classified as Typic Dystrudepts.