In-situ multi-sensor characterization of soil cores along an erosion-deposition gradient

• Published in: Catena (Giessen) Vol. 182; p. 104140
• Main Authors: Leue, Martin, Hoffmann, Carsten, Hierold, Wilfried, Sommer, Michael
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-11-2019
• Subjects: Digital soil morphometrics; DRIFT spectroscopy; Soil erosion; Soil organic carbon; VIS-NIR spectroscopy; XRF spectroscopy; Digital soil morphometrics; VIS-NIR spectroscopy; Soil erosion; XRF spectroscopy; Soil organic carbon; DRIFT spectroscopy
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2019.104140

Soil landscape research is faced with wide-ranging questions of soil erosion, precision farming, and agricultural risk management. Digital Soil Morphometrics is a powerful tool to provide respective answers or recommendations but requires soil data from the pedon-to-field scale with high horizontal and vertical resolutions, including the subsoil. We present an efficient sampling and measurement method for easily obtainable soil driving cores with low-destructive preparation. Elemental contents and soil organic and mineral matter composition were measured rapidly and in large numbers using a multi-sensor approach, i.e., visible and near-infrared (Vis-NIR), diffuse reflectance infrared Fourier transform (DRIFT), and X-ray fluorescence (XRF) spectroscopy. The suitability of the approach with respect to three-dimensional soil landscape models was tested using soils along a slope representing different stages of erosion and deposition in a hummocky landscape under arable land use (Calcaric Regosols, Calcic Luvisols, Luvic Stagnosols, Gleyic-Colluvic Regosols). The combination of soil core sampling, pedological description, and three spectroscopic techniques enabled rapid determination and interpretation of horizontal and vertical spatial distributions of soil organic carbon (SOC), soil organic and mineral matter composition, as well as CaCO3, Fe, and Mn contents. Depth profiles for SOC, CaCO3, and Fe contents were suitable indicators for site-specific degrees of erosion and matter transport processes at the pedon-to-field scale. Fe and Mn profiles helped identifying zones of reductive and oxic domains in subsoils (gleyzation). Further methodical developments should implement plant-availability of nutrients, characterization of Fe-oxides, and calibration of the spectroscopic techniques to field-moist samples.
•An efficient sampling and measurement method for undisturbed soil cores is presented.•Detection of element contents and SOM composition in high horizontal and vertical resolution•Combination of pedological description, Vis-NIR, DRIFT, XRF, and laboratory analyses•Stages of erosion and deposition assigned to soil properties, e.g. SOC, CaCO3, Fe contents•Spatial Mn and Fe distributions (vertical, horizontal) reflect different redox domains.