Comparing electromagnetic induction and ground penetrating radar techniques for estimating soil moisture content

Previous studies have demonstrated the capacity of electromagnetic geophysical methods for estimating soil moisture content. In this study, electromagnetic induction (EMI) and ground-penetrating radar (GPR) measurements were coincidently collected along a fixed survey line to evaluate temporal changes in apparent electrical conductivity and electromagnetic direct ground wave velocity, respectively; surveys were collected at three sites (i.e., sand, sandy loam and silt loam) during the course of a complete annual cycle of soil conditions. These two geophysical data sets correlated well during the course of the annual cycle at the silt loam site. Correlation between the two data sets was not as strong at the other two sites, with the sand site showing the lowest correlation values. Further, the geophysical data and gravimetric water content measurements obtained from the upper 0.5 metres indicate higher correlation estimates at the finer grained silt loam site relative to the sand and sandy loam sites.