Managing Global Resources for a Secure Future

When trying to understand soil water dynamics soil water content and water potential are critical parameters to understand. Historically we’ve been forced to make these measurements with two separate sensors. This added cost, site disturbance, and challenges with colocation. Currently there is not a single sensor commercially available that combines a measurement of water content and water potential. Yet, the idea of combining the two is often mentioned as a key piece for field monitoring in soil physics and geotechnical engineering. We took two commonly used sensors for soil moisture: tensiometers for water potential and capacitance for water content integrated them into a single, cylindrical sensor that can be easily and snuggly inserted into soil to a considerable depth. Lab calibrations showed the capacitance technology to accurately measure water content across a broad range of soil types while the tensiometer element showed the exceptional accuracy expected from an instrument of this type. Field-testing at two locations, in Braunschweig, Germany and in Pullman, WA, showed good performance compared to other installed sensors. The proper co-location of these two measurements can enable us to collect better in-situ soil moisture release curves, understanding slope stability, and better understand soil water dynamic