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Conventionally, soils have been characterized based on their physical, chemical and mineralogical characteristics. However, in order to address various geo-environmental issues that have become a threat for the modem day civilization, soils have also been characterized based on their electrical properties. Furthermore, it has been demonstrated that the electrical properties of the soil mass (i.e., the soil compacted at a certain dry density and water content) are instrumental, primarily, in measuring its volumetric moisture content. In this context, though several efforts have been made by earlier researchers to determine dielectric response of the soil mass, the effect of soil magnetic characteristics on dielectric response and volumetric moisture content has not been established yet. Hence, development of a methodology to determine magnetic characteristics and their relationship with the dielectric response of the soil mass, if any, becomes quite intriguing. With this in view, soils of entirely different characteristics were tested for their magnetic characteristics (viz., remnant magnetization, coercivity and magnetic hysteresis area) by employing a magnetometer. Furthermore, these characteristics have been correlated with the physical, chemical, mineralogical and electrical properties (dielectric dispersion obtained from an impedance analyzer) of the soil. The study demonstrates that the parameter "area of magnetic hysteresis" of the air dried soils has significant influence on soil specific parameters such as specific gravity, iron content and dielectric constant. This preliminary study also proposes a hypothesis to obtain volumetric moisture content of the soil mass based on its magnetic characteristics and dielectric constant, which can be obtained from an impedance analyzer. However, efficiency and utility of the proposed hypothesis should be demonstrated by testing a large number of soils from different parts of the world.

This technical note deals with the fabrication and details of an electrical resistivity box and an electrical resistivity probe, for estimating soil electrical resistivity. Calibration of these setups has been done with the standard KCl and NaCl solutions. Using this calibration, electrical resistivity of a locally available silty soil and commercially available white clay has been determined. Further, efforts have been made to develop relationships between the electrical resistivity of these soils and their saturation. Results available in the literature have been used to validate these relationships.