If the CS616/CS625 is providing an accurate volumetric water content (VWC) measurement in a mineral soil that follows a standard permittivity to water content equation such as Topp et al. or Ledieu et al., the relative dielectric permittivity, Ka, may be calculated. A good estimate of Ka is obtained with the following equation:
Ka = ((VWC + 0.176)/0.115)2, where VWC is fractional volumetric water content.