Geophysical methods for soil applications

Traditional methods to assess soil properties or monitor soil processes typically rely on point data. They often fail to represent the heterogeneity of soil. Airborne remote sensing techniques allowed us to measure proxies for soil properties or variables at regional scale, but often covering only the first few centimeters of soil. Ground-based geophysical methods can fill in the gap between these two scales. They primarily observe variations in the thermal, electrical, magnetic, electromagnetic or seismic properties of the subsurface to map its characteristics or to monitor dynamic changes and can yield 2- or 3-D quantitative information on soil properties or processes. Geophysical methods have been applied in various soil-related research fields: from soil mapping and precision agriculture, to geotechnical engineering and soil remediation and to archeology and forensic investigation. This chapter briefly introduces the ground-based geophysical techniques appropriate for soil applications.