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The traditional soil equivalent circuit model is simply combined by a capacitor and resistor in parallel. But this model doesn't work out in a wide frequency range and a lot of electrical properties of soil cannot be reflected by this model. So it is valuable to develop a new soil equivalent circuit model that has actual physical meaning to carry out quantitative analysis on soil properties and to predict soil electrical behaviors over a wide frequency range. In this paper, a novel soil equivalent two-phase circuit model is proposed, and then the impedance characteristics of soil are measured and studied. The variation trend of the measured soil impedance spectroscopy curve is consistent with the impedance characteristics of the equivalent circuit model, so it can be considered that the soil equivalent two-phase circuit model proposed in this paper is rational. The frequency range below 10MHz is determined as the suitable measurement signal frequency range to measure the soil resistivity, and 1MHz was taken as the measurement frequency to calculate the corresponding relationship between the soil resistivity and the soil water content. As a result, the measurement of soil moisture can be implemented indirectly by measuring the soil resistivity. This method requires simple measuring equipment and low cost, so that it can be used as a rapid measurement method of soil moisture content, which has a broad application prospect.
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