Design and Calibration of Soil Water Content Sensor Based on Dual Frequency Excitation

Accuracy of capacitance moisture sensors is typically deteriorated on account of soil bulk electrical conductivity effect. In this work, a low-cost capacitance sensor with dual frequency excitation for soil water content measurement was proposed. Then, a two-step calibration method was presented to reduce soil bulk electrical conductivity effect on soil water content. Firstly, the mathematical mod...