Nadler, A., Agricultural Research Organization, the Volcani Center, Bet Dagan 50250, Israel.
Dasberg, S., Agricultural Research Organization, the Volcani Center, Bet Dagan 50250, Israel.
Lapid, I., Dep. of Isotope Research, the Weizmann Institute of Science, Rehovot 76100, Israel

Time domain reflectometry (TDR) was used for simultaneous measurement of soil water content, θ, and bulk soil electrical conductivity, σ, for uniform and layered soil profiles in the laboratory. The purpose of the study was to test the different concepts of travel time and attenuation by using independent estimates of θ and σ than those of the two-rod probe. TDR measurements of θ for layered profiles were not always accurate, especially when wet soil was overlying dry soil, due to erroneous interpretation of the TDR trace. This study reports a new method of calculating σ, which is simpler than previous ones and independent of multiple reflections, was found to correlate better than the previously published methods with another, independent four-electrode technique. -from Authors