Improvement of a dual-sensor horizontal penetrometer by incorporating an EC sensor

Following the development of a dual-sensor horizontal penetrometer for the simultaneous measurements of soil water content and strength, an electrical conductivity (EC) sensor with a 4-ring Wenner-array was incorporated into the cone of the horizontal penetrometer. In order to overcome the cross-modulation of signals from water content and EC sensors, two filters with specific pass-bands were connected in each circuitry. Both laboratory calibration and field test were conducted, and the experimental results showed that the improved technique could provide more informative data to interpret soil physical conditions at field-scale.