First results from a millimetre-wave measurement of soil moisture content

The method presented in this letter enables, for the first time, quantitative assessment of soil moisture content in the upper part of the root zone using remote sensing. The data are obtained in a short time and at low cost. We present results of measurements following water application at various cumulative energies by Morin's rainfall simulator. The method is based on the emerging technology of millimetre waves, providing improved resolution of the subsurface concurrent with surface mapping. Development and use of the tools described herein will make it easier to understand processes occurring at the soil-water interface, such as soil crusting, penetration, run-off and erosion. We emphasize the difference between the suggested technique based on microwave radiation at millimetre wavelengths with excellent resolution and microwave radiation with a wavelength of tens of centimetres and thus reduced resolution.