In the Wenner Four-Pin Method, what does the average soil resistivity depend on?

In the Wenner Four-Pin Method, the average soil resistivity is determined by measuring the voltage drop between the center pins while a current flows through the outer pins. This method involves applying a known current and measuring the resulting voltage, allowing for the calculation of resistivity based on Ohm's Law (Resistivity = Voltage / Current).

The arrangement with four pins helps to minimize the influence of ground resistance and provides a more accurate reading of soil resistivity over a defined spacing. The voltage drop measured at the center pins directly reflects the resistivity of the soil through which the current is flowing.

Thus, the average soil resistivity is intrinsic to the voltage drop observed and the current used, making the measurement between the center pins critical in achieving accurate results. The accuracy and reliability of the Wenner method hinge on this voltage measurement, which is why it is the core factor in determining soil resistivity.