The Effect of Moisture on the Electrical Properties of Soil

Measurements of the dielectric constant of soil containing different known percentages of moisture were made at a fixed frequency of 430 Mc/s. The method adopted involved the use of a coaxial transmission line terminated with a sample of the soil under test The line consisted of a central rod with a concentric tube about 2½ metres in length. Measurements were made with soil samples containing from 4.1% to 47.7% moisture The dielectric constant was found to vary from 4.0 to 31.4 The values are shown graphically and compared with those obtained by nine other authors. The conductivity could not be measured accurately with the method used, but it was estimated to vary from about 1 5 × 10⁹ e.s u with 4% moisture to 4 × 10¹⁰ e.s u with 50% moisture