Experimental Electrical Modeling of Soil for In Situ Soil Moisture Measurement

Wet soil is a heterogeneous mixture and involves a lot of complexities in terms of its electrical properties. Different parameters that affect electrical properties of the soil are type of the soil, density, operating frequency, water content, soluble salts and minerals. Due to this complex nature it is a challenge to develop a universal electronic system for moisture measurement. Therefore design of the measurement system, particularly for in-situ applications, needs an experiment-based electrical model of the soil. This paper presents an experiment-based electrical modeling of white clay soil, applicable for frequency range of 40Hz to 1.26MHz, which can be used to represent the same soil in any soil moisture circuit and system design. This model is then used to design an LC oscillator for soil moisture measurement. Testing of equivalent electrical circuit of white clay with LC oscillator shows correctness of the equivalent electrical model.