Masters Theses

Date of Award

12-1990

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

John T. Ammons

Committee Members

Russell Lewis, Darwin Newton

Abstract

Soil and landform relationships were studied on a group of soils developing from parent materials belonging to the Mississippian Grainger formation, the Cambrian Rome formation and the Cambrian Conasauga group in eastern Tennessee. The Conasauga group is made up of the Pumpkin Valley shale, Rutledge limestone, Rogersville shale, Maryville limestone, Nolichucky shale and Maynardville limestone. These are middle to late Cambrian age lithologies.

Alfisols, Inceptisols and Ultisols were the prevalent soil orders forming on this landscape. Alfisols occurred where high base parent materials were weathering and where agricultural practices were contributing bases to the soil environment. Alfisols were present on the Grainger formation. Pumpkin Valley shale, a deep alluvium overlying the Rutledge limestone, on the Maryville limestone and the Maynardville limestone. High base Inceptisols were forming on the flood plain of Richland Creek and in the Grainger formation. Low base Inceptisols were forming on the Rome formation. Ultisols developed in the residuum from the Rutledge limestone and Nolichucky shale.

This is an evolving landscape. With the exception of some deep, relatively well developed soils on more stable landscape components, there was little indication of stability among the landforms. Field studies revealed little accumulation of colluvium, except in some larger coves associated with the Grainger formation. It seems that geologic erosion has precluded the placement of deep colluvial deposits on most of this landscape. There was evidence, however, of relatively shallow layers of colluvium overlying some of the pedons observed.

An obvious relationship between degree of soil development and relief was observed, to the extent that on all but the most gentle slopes, the effect of relief was the overriding soil forming factor, obscuring much of the contribution of the parent material. On the stable landscape components, time, climate (or paleoclimate) and parent material were dominant factors of soil formation. High base saturation was observed in the upper parts of profiles on the Rutledge limestone unit. This high content of bases was not readily attributable to a single soil forming factor. Agricultural practices are thought to play some role in the high base content of these soils, but cannot account for all of the bases present in the upper meter or so of these profiles. It would seem that the bases are somehow being laterally translocated in this part of the landscape.

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