Multi-TDR probe designed for measuring soil moisture distribution near the soil surface.

To establish a method for monitoring the vertical profile of volumetric water content ( �) near a soil surface, a multi-TDR (time domain reflectometry) probe was designed and applied to �-profile observations during the evaporation processes for sand soil and decomposed granite soil (DG soil). The multi-TDR probe consists of 8 sets of 3-line TDR probes, being on a print-circuit board with a low dielectric constant and able to measure dielectric constant ( �Multi-TDR ) at intervals of 3 mm. We individually calibrated the probes for sand with