| Abstract Submission No. | ABS-4.1-0230 |
| Title of Abstract | Soil Water Retention Curve using a Dielectric Permittivity Regression |
| Authors | Keith Bellingham* |
| Organisation | Stevens Water Monitoring Inc. |
| Address | 12067 NE Glenn Widing Dr #106 Portland, Oregon, India Pincode: 97220 E-mail: ageorge@stevenswater.com |
| Country | India |
| Presentation | Poster |
| Abstract | The understanding of the movement of water through soil has many applications. The Richards Equation has become one of the most common ways to describe and quantify the transient movement of water in unsaturated porous media which uses the unsaturated hydraulic conductivity. The unsaturated hydraulic conductivity is important for both physical and statistical models. Hydraulic conductivity is determined from a water retention curve which is a plot of soil moisture verses unsaturated hydraulic head. The water retention curve, however, is often difficult to obtain in the laboratory and difficult to apply to soil moisture data in the field. A fixture called The Travel Assembly has been developed to hold a soil sensor in a soil sample during the laboratory development of a soil water retention curve. The Travel Assembly is a fixture that holds the soil sample with a HydraProbe, so that it can be pressurized up to 15 bar. The resulting soil water retention curve can then be correlated with the HydraProbe. Upon completion of the soil water retention curve, HydraProbes in the field in the same soil tested are able to measure soil moisture very accurately with a custom calibration, and unsaturated hydraulic head. With this information and the unsaturated hydraulic conductivity can then be calculated using the van Genuchten equation. Six soil samples were placed in the Travel Assembly and evaluated at saturation and 10 pressures ranging from 0.01 to 5 Bar. The technique was perfected to generate a soil water retention curve with minimal error. |
| Keywords | Hydraprobe, Van Genuchten equation, Unsaturated Hydraulic head, Water retention curve, Travel assembly. |