Prediction of the distribution of soil properties in deep Colluvisols in different pedogeographic regions (Czech Republic) using diffuse reflectance infrared spectroscopy

• Published in: Soil & tillage research 2023-10, Vol.234, p.105844, Article 105844
• Main Authors: Pavlů, Lenka, Zádorová, Tereza, Pavlů, Jiří, Tejnecký, Václav, Drábek, Ondřej, Rojas, Jessica Reyes, Thai, Saven, Penížek, Vít
• Format: Article
• Language: English
• Subjects: Colluvial soils; DRIFT spectroscopy; Organic matter quality; Soil erosion; Spectra normalization
• ISSN: 0167-1987; 1879-3444
• DOI: 10.1016/j.still.2023.105844

Colluvisols form a significant part of the erosion–deposition soil catena mainly in undulating, agriculturally managed landscapes. Due to their sedimentary origin, they are soils with highly variable properties. For such diverse and often extremely deep soils, it is essential to capture the vertical distribution of properties in as much detail as possible. This study demonstrates the potential of the diffuse reflectance infrared spectroscopy (DRIFT) to derive accurate information on the stratigraphy and selected soil properties (soil organic carbon and calcium carbonate contents and aluminium and iron concentrations) of deep colluvial profiles in three regions in the Czech Republic with different dominant soil types (Chernozem, Luvisol, and Cambisol). The normalization of the spectrum using the quartz spectral band was found to be suitable for assessing the carbonate content in Chernozems and Luvisols (coefficients of determination (R2) were 0.89 and 0.88, respectively). The amount of organic carbon can be predicted from such normalized spectra with less confidence (R2 = 0.64). Organic matter quality as an indicator of their stability and maturity was computed from aliphatic compounds spectral bands (2930 cm–1) and aromatics and CO groups band around 1640 cm–1. The highest values of this indicator were found in Colluvisols in the Chernozem region (> 6, while, e.g., in the Cambisol region it is