Soil water movement along a loess and alluvium interface in West Tennessee

Author

Holly Ann Carter

Date of Award

12-1996

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

John T. Ammons

Committee Members

Ron Yoder, Michael Essington, Vernon Reich

Abstract

Ongoing water quality research at the University of Tennessee Ames Plantation Agricultural Experiment Station in west Tennessee, has provided opportunity to examine the factors affecting soil water movement, for applications in determining the fate of agricultural chemicals. This research was to create a high intensity, order one soil survey map of the research plot, and to examine the effects of soil morphology on the direction of soil water movement.

In order to establish general morphology of the research area, four soil cores equally spaced in a 15.24 meter linear transect were taken with a Giddings-S-M hydraulic probe using a 7.62 cm sampling tube. Morphology of each core was recorded in the field. Individual horizons of each core were sampled and taken to the laboratory for determination of; total carbon, particle size, citrate-dithionite extractable iron oxides, KCI exchangeable acidity, hydroxylamine-hydrochloride extractable manganese, exchangeable bases, cation exchange capacity, free carbonates, and pH. Moist sub-samples of each horizon were refrigerated for determination of background chloride levels. Based on field morphology notes and laboratory data, the four transect cores were classified to the family level, as fine-silty, mixed, thermic Typic Hapludalfs.

The soil morphology for 32 cores surrounding a 0.05 hectare release area on the research plot were recorded. Alluvium was found underlying the surface loessial layer across the entire plot. Based on the depth to this alluvial paleosol and soil morphology, a high intensity, order one soil survey map was created. Surface and paleosurface topography and 3-dimensional surface maps were also made based on measured elevations and depths.

Shallow sampling wells were set to the depth of the alluvium in each of the 32 holes where the cores were taken. A prediction as to which wells would receive water based on their topographic position on the alluvial surface, and also a prediction of the general expected direction of movement across the plot were made. A 527 m² tracer release area was established in the center of the previously designated release area. A calcium chloride tracer solution was applied to the release area and allowed to move into and through the soil, after which wells that yielded water were sampled. A total of two background and three post-release sampling events occurred, lon-chromatography results reflecting background and post-release chloride levels were statistically inconclusive, and could not be used to prove or disprove the validity of the prediction. Instead, the presence of water samples in a well on all three sampling dates was considered to make that well a consistent receptor. While individual wells were not very successfully predicted, the general direction of soil water movement was quite accurately forecasted.

Recommended Citation

Carter, Holly Ann, "Soil water movement along a loess and alluvium interface in West Tennessee. " Master's Thesis, University of Tennessee, 1996.
https://trace.tennessee.edu/utk_gradthes/6841