The Aridisols of the Atacama Desert remain poorly explored pedologically using proximal sensing techniques, such as combined geophysical methods, which can provide information on various pedogeophysical variables, including radionuclides, magnetic susceptibility (κ), and soil apparent electrical conductivity (ECa). Studies in this context can provide important insights into weathering, pedogenetic, and geomorphological processes in the region and support soil mapping. Among the advantages of geophysical methods are rapid data acquisition, non-invasive nature, the ability to accurately detect soil subsurface information, and their operational simplicity in the field. This study aimed to characterize Aridisol profiles in the Atacama Desert using a combination of three geophysical techniques (gamma-ray spectrometry, κ, and ECa) in a heterogeneous area with respect to soil-forming factors (lithology, climatic conditions, and relief variability). It also aimed to relate pedogeophysical variables to diagnostic horizons and soil attributes and to explore the relationships between pedogeophysical variables and soil-forming factors. For that, we employed the combined use of gamma-ray spectrometry, soil κ, and soil ECa measured with proximal geophysical sensors, integrated with morphological descriptions and laboratory analyses (chemical, physical, and mineralogical) to validate the field pedogeophysical data. Nine soil profiles were characterized using depth-resolved sensors. Statistical analyses were performed in the R software environment, including mean comparison tests, multivariate analyses, spearman correlation, and visualization of the vertical distribution of pedogeophysical variables across Aridisol profile. Our results revealed a hierarchical control over the magnitude and distribution of pedogeophysical variables. Lithology exerted the strongest influence, acting as the primary source of radionuclides and ferrimagnetic minerals and controlling salt dissolution and precipitation. Climate conditions limited radionuclide leaching and governed soil moisture and salt precipitation conditions in most profiles affecting ECa values. Geomorphology influenced erosion processes and the aeolian deposition of allochthonous materials with distinct compositions, which was reflected in the concentrations of ferrimagnetic minerals and radionuclides content. Pedogenesis, although active, exerted a comparatively minor influence on overall levels of geophysical variables, particularly radionuclides, but played a more important role in their vertical redistribution within the Aridisol profiles. Differences in pedogeophysical variables among diagnostic horizons were observed across the Aridisol profiles and were consistent with morphological observations and laboratory analytical data.
Moreira et al. (Thu,) studied this question.