Document Type

Thesis - Open Access

Award Date

1985

Degree Name

Master of Science (MS)

Department

Agricultural Engineering

First Advisor

A.R. Bender

Abstract

The union of pressure transducer and tensiometer ceramic cup was termed "transiometer". Construction and installation procedures for a transiometer were presented. The transiorneter can be used in both saturated and unsaturated conditions. In saturated conditions, it has a faster response than a piezometer, making it very useful in fine-textured, slowly permeable soils. The primary transiometer study site, at the RCWP Master site, consisted of four replications each of transiometers installed at depths of 1.22 m, 1.83 m, 3.66 m, and 6.10 m, along with a sensor without the ceramic cup installed at a depth of 3.66 m. The sensors placed within 2 m of the ground surface were in the unsaturated zone. A piezometer, placed at a depth of 6.10 m, and neutron probe access tubes, for soil moisture monitoring to a depth of 5.18 m, were also installed in each of the four plots. Thermistors were installed in one plot at depths of 15, 30, 61, and 91 crn. An auxiliary site was established with a transiorneter placed at a depth of 5.03 m, piezometers placed at depths of 2.26 m and 3.76 m, and a neutron probe access tube to monitor soil moisture to a depth of 3.35 m. ii Random error of the measuring system of transiometer, digital voltmeter, and scanner was typically 2.8 cm with a maximum of 11.5 cm. The two most significant components of measuring system random error were the potential created at the connection terminals of the scanner and the imprecision of the transducer calibrations. The transiometer was very sensitive to atmospheric pressure fluctuations, with the response to atmospheric pressure changes increasing with depth of installation. Saturated hydraulic conductivity of the glacial till monitored was 10-7 to 10-8 m s-l, while the drainable porosity was .025-.035.

Library of Congress Subject Headings

Soil moisture -- Measurement

Format

application/pdf

Number of Pages

107

Publisher

South Dakota State University

Rights

No Copyright - United State
http://rightsstatements.org/vocab/NoC-US/1.0/

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