Thermal Resistivity of Stony Soils: How To Get the Right Answer in a Soil/Rock Mix

Get the right thermal resistivity or thermal conductivity value for your soil profile. Find out how to combine rock and soil measurements.

You can’t directly measure the thermal resistivity or conductivity of a stony soil

Rocks typically have a much higher thermal conductivity than the soil around them. You can measure the thermal conductivity of the rocks and of the interstitial soil, but how do you combine them to get the conductivity or resistivity of the soil profile? If you average the two, you’ll end up with the wrong number, which could be catastrophic. In underground power cable applications, if you overestimate, you’re in danger of damaging the cable. If you underestimate, you’ll spend too much on your installation.

How to combine the conductivity of rock and soil to get the right value for the profile

In this 30-minute webinar, world-renowned soil physicist Dr. Gaylon Campbell teaches how to combine the conductivity of rock and soil to get the right thermal conductivity or thermal resistivity value for the soil profile. You’ll learn:

  • How to both measure and model soil thermal conductivity
  • How to measure the thermal conductivity of rocks
  • How to combine those two measurements to get the right conductivity value for the entire soil profile


Dr. Gaylon S. Campbell has been a research scientist and engineer at METER for over 20 years, following nearly 30 years on faculty at Washington State University. Dr. Campbell’s first experience with environmental measurement came in the lab of Sterling Taylor at Utah State University making water potential measurements to understand plant water status.

Dr. Campbell is one of the world’s foremost authorities on physical measurements in the soil-plant-atmosphere continuum. His book written with Dr. John Norman on Environmental Biophysics provides a critical foundation for anyone interested in understanding the physics of the natural world. Dr. Campbell has written three books, over 100 refereed journal articles and book chapters, and has several patents.

Next steps


Our scientists have decades of experience helping researchers and growers measure the soil-plant-atmosphere continuum. 

Rapid, in situ Thermal Conductivity Measurements—Even in Moist Insulating Materials

Dr. Gaylon Campbell shows how to measure the thermal conductivity of wet insulation with a 5-minute read time. These previously impossible measurements are now possible through advanced electronics and analytical methods.
Webinars40 min watch

Best practices for measuring thermal properties of fluids

Dr. Cobos gives practical considerations to improve the quality of fluid measurements. 
Webinars44 min watch

Soil Moisture 302: Hydraulic Conductivity—Which Instrument is Right for You?

Leo Rivera, research scientist at METER, teaches which situations require saturated or unsaturated hydraulic conductivity and the pros and cons of common methods.
Webinars47 min watch

Get case studies, webinars, and articles you’ll love

Receive the latest content on a regular basis.


METER Group, Inc. USA privacy policy statements.