PEAT WATER-CONTENT MEASUREMENT USING TIME DOMAIN REFLECTOMETRY

The calibration of time domain reflectometry, previously established for an organic soil of 0.422 Mg.m-3 bulk density, was established for peat blocks with bulk densities ranging from 0.06 to 0.25 Mg.m-3. An empirical relationship between the volumetric water content and the measured apparent dielectric constant was established in the laboratory. This relationship can be used to estimate volumetric water content between 0.21 and 0.95 cm3.cm-3 with a standard deviation of 0.03 cm3.cm-3. The large variations observed during the calibration were mainly attributed to the size and heterogeneousness of peat samples. When water tables in the field were high, standard deviation decreased to 0.02 cm3.cm-3, which agrees very well with other time domain reflectometry experiments.