The role of organomineral gel in the origin of soil resistivity: Concept and experiments

摘要

A concept suggesting that soil colloids form an integral structure-organomineral gel-is developed. The organomineral gel consists of colloidal particles of clay minerals, iron and aluminum hydroxides, silica, and organic substances. This gel covers the surface of noncolloidal particles and links them with one another. The soil solution is also included in the composition of the organomineral gel. The four-electrode method has been applied to measure the specific resistance in a number of soils at constant and alternating currents under different moisture and temperature conditions. It has been found that the soil resistivity increases upon low current frequencies (10-30 Hz) and low intensities of the electric field. It also increases with time for the absolutely dry and then moistened soils. These facts support the hypothesis about the inclusion of the soil solution into the organomineral gel system.