Use of electrical soil-moisture units in mountain soils

A procedure for measuring soil moisture at several depths in a mountain soil mantle using fiberglass, monel metal units (Colman Units) is presented. These units have a thermister (temperature element) encased in the monel metal case. Three wire leads are brought to the surface through a pipe to prevent rodent damage. The meter is an alternating current design circuit to measure impedance In milli-amps, thus averting a direct resistance reading that would be contaminated by soil salts or acids. The milli-amps readings are converted to Ohms by a calibration chart furnished with each meter. The process of calibrating the units to soil moisture by field and laboratory procedures is discussed. Calibration curves are exhibited. A discussion of results is included in the text of the paper.