Soil electromagnetic parameters as functions of frequency, soil density, and soil moisture

Measurements are made to determine the conductivity and dielectric constants of a gray clay loam and a reddish-brown clay loam. The measurements are made as a function of soil density (from 1.2 g/cm³to 1.8 g/cm³), soil moisture (from 0 percent to 20 percent of the dry soil weight), and excitation frequency (from 30 MHz to 4 GHz), using standard transmission line techniques. A correction term is presented to allow the effective open-circuit and short-circuit connections to be placed at any convenient location with respect to the soil-air interface.