Probe assembly for measuring resistivity of a soil, and method thereof

A probe assembly for measuring resistivity of a soil is connected to a measuring apparatus capable of generating a constant DC current signal into two electric leads. The probe assembly includes a short circuit connector; double-pole double-throw switch having two fixed contacts, and two switched contacts alternatively connectable to the electric leads or to the short circuit connector, respectively; and two electrodes connected to the fixed contacts respectively. Each of the electrodes has a portion of its surface forming a conductive surface. The conductive surfaces are substantially opposite to each other when the electrodes are put into the soil. In a stand-by position, the switched contacts are connected to the short circuit connector. In an operating position for measurement, the switched contacts are connected to the electrical leads, whereby when a measurement is performed, the switched contacts are switched from the stand-by position to the operating position so that the DC current signal can be injected into the electrodes and produce a voltage between the electrical leads that is indicative of the resistivity of the soil between said electrodes.