LABORATORY EVALUATION OF A FIELD-PORTABLE DIELECTRIC SOIL-MOISTURE PROBE

There has been a need for a rapid method of collecting soil-moisture information, especially for verifying microwave remote sensing field experiments. In this investigation an evaluation of an L-band dielectric probe was conducted to examine its capabilities, calibration, and performance under laboratory conditions. Results indicated that the probe can estimate the real part of the dielectric constant over a wide range of values. The imaginary part of the dielectric constant was overestimated. Since the soil moisture estimate is made using only the real part of the dielectric constant, the probe should produce reliable estimates of soil moisture. Studies utilizing a variety of soils, ranging from a loamy sand to a clay loam, produced results which were not as variable as those predicted by the dielectric models. © 1990 IEEE