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(ϵc)½ − 0.204.

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