Dielectric Dependence On Salinity And Probe Length In Tdr-Measurements

Time domain reflectometry (TDR) is widely used in soil sciences and forestry to determine soil<br>dielectric properties and water content. The effects of TDR probe length, geometry and water<br>electrical conductivity (%) on dielectric values were studied. The three-prong TRD probes, 0.06<br>m in diameter and lenght varying from 0.035 to 0.15 m with varying the spacing of the probes<br>tested in water, whose electrical conductivity (%) varied from 0.6 mS/m to 700 mS/m. The<br>scattering in dielectric values increased significantly, when the probe lengt was 0.035 m or<br>shorter. However, the scatter level was minor with probes bend outward or inward. Probe<br>spacing greater than 0.06 m resulted in unreliable readings. The increase of electrical<br>conductivity of water with %> 200 mS/m resulted in scattered data, particularly with the 0.035-<br>m-long probes. Dielectric data for all probe lenghts were scattered with water electrical<br>conductivity with oW> 500 mS/m.