Measurement of Soil Thermal Properties with a Dual-Probe Heat-Pulse Technique

Bristow, Keith L.; Kluitenberg, Gerard J.; Horton, Robert

Measurement of Soil Thermal Properties with a Dual-Probe Heat-Pulse Technique

1994

Bristow, Keith L. | Kluitenberg, Gerard J. | Horton, Robert

Although soil thermal properties are required in many areas of engineering, micrometeorology, agronomy, and soil science, they are seldom measured on a routine basis. Reasons for this are unclear, but may be related to a lack of suitable instrumentation and appropriate theory. We developed a theory for the radial conduction of a short-duration heat pulse away from an infinite line source, and compared it with the theory for an instantaneously heated line source. By measuring the temperature response at a short distance from the line source, and applying short-duration heat-pulse theory, we can extract all the soil thermal properties, the thermal diffusivity, heat capacity, and conductivity, from a single heat-pulse measurement. Results of initial experiments carried out on air-dry sand and clay materials indicate that this heat-pulse method yields soil thermal properties that compare well with thermal properties measured by independent methods. Contribution no. 93-430-J from the Kansas Agric. Exp. Stn., Manhattan, KS. Journal paper no. J-15353 of the Iowa Agric. Home Economics Exp. Stn., Ames, IA.

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