Influence of gravimetric water content and bulk density on the dielectric properties of soil

Summary Moisture content and bulk density largely characterize physical and mechanical soil status and behaviour. A nondestructive determination of these soil properties is essential. Time domain reflectometry (TDR), although widely accepted for determination of volumetric water content, θ , has its limitations, and recently a frequency domain (FD) sensor has been developed and tested. An equation relating relative permittivity, ɛ′, to gravimetric water content, w , and bulk density, p , was established for three soil types (sand, sandy loam and clay). If ɛ′ and w are known, our model can be used to calculate bulk density and associated volumetric water content, θ , keeping in mind that θ= pw. Utilization is found in long‐term monitoring of moisture fluctuations or short‐term detection of traffic‐induced soil compaction.