TIME DOMAIN REFLECTOMETRY FOR MEASURING SOIL-WATER CONTENT IN RANGE SURVEYS

Time Domain Reflectometry (TDR) is introduced as a viable alternative for measuring soil water content for rangeland surveys. The method is based on a strong relationship between the complex dielectric constant of soil and volumetric soil water. Volumetric water content (theta(v)), measured by TDR and gravimetrically, was compared for 2 rangeland sites. TDR underestimated theta(v) when compared to gravimetric samples for all data. Potential causes of this error and possible solutions are discussed. Some advantages and disadvantages of the method are discussed.