Technical Report - Evaluation of a Roving Capacitance Probe for Measuring Soil Moisture
Abstract
In the Proserpine area of central Queensland, Australia, trials were conducted to evaluate the performance of a proving capacitance probe for determining soil moisture. Soil moisture was monitored using both a neutron moisture meter (NMM) and a roving capacitance probe on seven different soil types at depths between 0.20 and 1 m. Volumetric soil moisture was also determined from core analysis. While the capacitance probe was more accurate when used with specific site or soil type calibrations, a general calibration was believed to be acceptable for most purposes. The calibration supplied with the sensor produced considerable error. The capacitance probe was quick, cheap and simple to use with a similar level of accuracy to that of the neutron probe. Difficulties with the capacitance probe resulted from poor installation of access tubes, and development of cracks around the access tube in cracking clay soils.