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Studies on methods of soil moisture determination Item Info

Though the need for instrumentation capable of determining soil moisture quickly and accurately has long been recognized, no dependable means suitable for automatic and remote soil moisture measurement has yet been developed. Presently, the only reliable method for measuring soil moisture is a time consuming process which requires human attention. Water is removed from a soil sample by heating, and the resultant weight loss is determined. Considerable work has been reported on a device which measures the electrical conductivity of a gypsum block imbedded in the soil. Water causes the electrical resistance of the block to decrease. These blocks are alleged to be unreliable under many field conditions. The work reported in this thesis was undertaken with the intent to develop a more reliable instrument for remote site operation. An extensive survey of the literature led to the selection of three fields of study: streaming potential, thermal conductivity and specific heat, and absorption of infrared radiation by moist soil. Experimentation revealed that the factors controlling streaming potential were so diverse that isolation of soil moisture or moisture flow variables was not feasible in field applications. An original thermal measuring device could be successfully and reliably used in certain ambient temperature ranges. Certain wavelengths in the infrared spectrum are readily absorbed by moisture in the soil. A prototype instrument which utilizes this phenomenon was fabricated.

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Title:
Studies on methods of soil moisture determination
Authors:
Hite, Howard Eugene
Date Created (ISO Standard):
1968-04
Description:
Though the need for instrumentation capable of determining soil moisture quickly and accurately has long been recognized, no dependable means suitable for automatic and remote soil moisture measurement has yet been developed. Presently, the only reliable method for measuring soil moisture is a time consuming process which requires human attention. Water is removed from a soil sample by heating, and the resultant weight loss is determined. Considerable work has been reported on a device which measures the electrical conductivity of a gypsum block imbedded in the soil. Water causes the electrical resistance of the block to decrease. These blocks are alleged to be unreliable under many field conditions. The work reported in this thesis was undertaken with the intent to develop a more reliable instrument for remote site operation. An extensive survey of the literature led to the selection of three fields of study: streaming potential, thermal conductivity and specific heat, and absorption of infrared radiation by moist soil. Experimentation revealed that the factors controlling streaming potential were so diverse that isolation of soil moisture or moisture flow variables was not feasible in field applications. An original thermal measuring device could be successfully and reliably used in certain ambient temperature ranges. Certain wavelengths in the infrared spectrum are readily absorbed by moisture in the soil. A prototype instrument which utilizes this phenomenon was fabricated.
Subjects:
soil water
IWRRI number:
196810
Rights:
In copyright, educational use permitted. Educational use includes non-commercial reproduction of text and images in materials for teaching and research purposes. For other contexts beyond fair use, including digital reproduction, please contact the University of Idaho Library Special Collections and Archives Department at libspec@uidaho.edu. The University of Idaho Library is not liable for any violations of the law by users.
Publisher:
Engineering Experiment Station, University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
Jodi Haire
Date Digitized:
2008-03-06

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Preferred Citation:
"Studies on methods of soil moisture determination", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-196810.html
Rights
Rights:
In copyright, educational use permitted. Educational use includes non-commercial reproduction of text and images in materials for teaching and research purposes. For other contexts beyond fair use, including digital reproduction, please contact the University of Idaho Library Special Collections and Archives Department at libspec@uidaho.edu. The University of Idaho Library is not liable for any violations of the law by users.
Standardized Rights:
http://rightsstatements.org/vocab/InC-EDU/1.0/
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