Effect of saline water on emissivity of soil

Abstract

Complex permittivity (e’, e”) of sandy loam soil was measured in the frequency range 300 KHz - 1.5 GHz (using a vector network analyzer) and at 5.65 GHz (using microwave bench set up) for various moisture contents in the soil. Measurements for complex permittivity in this frequency range were also carried out for various salinity levels of water content in the soil. The emissivity of the soil for normal incidence was calculated from the measured value of complex permittivity. It has been observed that at a given microwave frequency, emissivity decreases with increase in moisture content in the soil. Further, the emissivity of the wet soil, above transition moisture, decreases with increase in salinity level in soil. The experimental data of complex permittivity and emissivity in this frequency range can be useful in detecting the salinity and moisture content in the soil.