TDR probes for the measurement of root zone soil moisture

Bolitho, Gary (2007) TDR probes for the measurement of root zone soil moisture. [USQ Project]

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[Abstract]: There can be no doubt that the efficient management of water resources is a topic that is highly relevant today. A decline in traditional levels of seasonal rain is impacting on rural and urban areas alike as public attention is directed towards recycling programs and public campaigns of efficient use of water. In agriculture, crop yields are directly related to soil moisture, levels that are most important at the root zone area of the plant.

There have been many technical approaches to the monitoring and control of soil moisture levels. One of the most convenient and accurate in-situ methods that has
established itself as a recognised standard around the world uses Time Domain Reflectometry (TDR) to determine volumetric water content of the soil.

TDR is most popularly used with soil probes (typically 30 - 60 cm in length) that are inserted directly into the soil and produce a soil moisture measurement that is averaged
over the length of the probes. More specific information such as the soil moisture in the root zone is not easily determined with such probes.

This project investigates an alternative TDR probe design that provides more information about the root zone area of interest. The launch of the TDR incident wave is from a point along the length of the probe, rather than from the start of the probe. Transmission line theory is used to determine the expected behaviour of the incident and subsequent reflection waves. 3D electro-magnetic design and simulation software is used as an aid to
the design process. A prototype probe has been designed and constructed, and laboratory tested for performance.

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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Additional Information: The raw data files stored as 144 Microsoft® Excel Worksheets, have been loaded as a Zip File.
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - Department of Electrical, Electronic and Computer Engineering (Up to 30 Jun 2013)
Date Deposited: 19 Jun 2008 23:44
Last Modified: 27 Sep 2022 04:19
Uncontrolled Keywords: TDR probes; Time Domain Reflectometry probes; measurement; root zone; soil moisture levels
Fields of Research (2008): 07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Fields of Research (2020): 30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3002 Agriculture, land and farm management > 300201 Agricultural hydrology

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