Measurement of soil capacitance using pulse width technique

Abstract

Soil water content is an important parameter in many engineering, agricultural and environmental applications. Capacitance measurement methods are used to measure the soil moisture or water content. Many capacitance soil moisture sensors employ a probe consisting of two electrodes. The capacitance between the probes varies as a function of water content in the soil. The capacitance measurement setup has been developed indigenously to measure capacitance of solid samples at low frequencies using integrated circuit of Monostable Multivibrator. The change in pulse width measured by using Tektronix TDS 2024 four channel digital storage oscilloscope. In this paper capacitance of soil samples from different locations of Pune district of Maharashtra State was measured at room temperature. The details of its interface to measure capacitance of soil samples and evaluated results are explained in this paper.