Soil water saturation: Dielectric determination

Dielectric measurements of moist soils are used to determine water saturations. The degree of saturation of water is determined using a mixing law for the composite structure (soil, water, and air) which is verified experimentally. For the lower water saturation range (<60%), a particularly simple form for the relationship between fractional water content θ and measured dielectric constant can be formulated. In particular, for sandy soils at 23°C, the fractional water content is given by θ = 0.128( ϵ c ) ½ − 0.204.