Using ground-penetrating radar to explore the cemented soil horizon in an arid region in Iran

Petrosalic horizon (cemented by soluble salts) is identified as a root-restricting layer in the arid and semi-arid regions. The knowledge of the variability of cemented layers within the soil profiles provides valuable information to decision-makers for agricultural and/or engineering activities. This study was conducted to evaluate the potential of ground-penetrating radar in detecting petrosalic horizon within the soil pedon in an arid area (Kerman Province, southeastern Iran). The measurements were performed using an impulse ground-penetrating radar system with a centre frequency of 250 MHz along ten parallel transects of 100-m length and 10-m distance between two consecutive transects at two sites. The results of the soil stratigraphy indicated the presence of petrosalic horizons at 12- to 36-cm depth. The ground-penetrating radar images showed patterns corresponding to these soil horizons. The interpreted radargrams were quite consistent with the findings of the soil pedons. It is, therefore, suggested that ground-penetrating radar could be employed to detect the boundaries between different soil horizons in the arid areas with various degrees of conductivity. This, in turn, helps differentiate soilmapping units and improve the reliability and accuracy of digital soil maps. The results confirmed that ground-penetrating radar could be used as a rapid, efficient and non-destructive tool providing highresolution and continuous visualisation of the soil horizons to detect the presence and depth of petrosalic horizons. Such information could be crucial in making decisions in agricultural practices (e.g., creating gardens) and engineering activities (e.g., constructing roads and buildings).