Quantifying hematite and goethite in hydromorphic soils using sentinel-2 and XRF data in the Beni Moussa perimeter, Tadla plain, Morocco

• Published in: Journal of Sedimentary Environments 2024-12, Vol.9 (4), p.997-1011
• Main Authors: Salmi, Abdessalam, El Baghdadi, Mohamed, Hilali, Abdessamad, Mosaid, Hassan
• Format: Article
• Language: English
• Subjects: cities; Earth and Environmental Science; Earth Sciences; Environment; Evolutionary Biology; Geography; Sedimentology; towns; Urban Geography; Urbanism (inc. megacities
• ISSN: 2662-5571; 2447-9462
• DOI: 10.1007/s43217-024-00196-4

This study evaluates Sentinel-2 bands’ effectiveness in detecting and quantifying ferrous products in soil. It proposes a methodology for quantifying ferrous products in parts per million (ppm) using specific spectral indices and iron absorption features. Existing indices adapted for Sentinel-2, like the hematite index (IHm) and the ferric index (RHGt PF ), are used to assess absorption features of ferrous products. Continuum-removal spectral feature analysis is used to quantify hematite and goethite minerals in Beni Moussa soils. Correlations are established between soil parameters and spectral responses, with multivariate statistical analysis aiding in discerning interrelationships among these parameters. The findings reveal that multispectral data from Sentinel-2 enable the detection of iron oxides, specifically hematite and goethite. Chemical analysis reveals that soil organic matter exceeds 10.00% in hydromorphic conditions, CaCO3 levels are mostly below 11.00% except in Oued Arich, and iron concentrations vary significantly, with values ranging from 11,107.50 ppm to 40,708.44 ppm, showing increasing levels downstream. Pearson correlation coefficients indicate significant positive correlations between iron content determined by X-ray fluorescence and the redness index ( r  = 0.94), as well as ferruginous minerals determined through spectral characteristics depth analysis for hematite ( r  = 0.89) and goethite ( r  = 0.83). The redness index also shows positive correlations with ferruginous minerals determined by spectral characteristics depth analysis for goethite ( r  = 0.84) and hematite ( r  = 0.89), while displaying negative correlations with organic matter ( r  = − 0.57) and CaCO3 ( r  = − 0.77), suggesting significant influences of these elements on soil iron concentration and electromagnetic spectrum. The strong correlation ( r  = 0.74) between the iron index ratio (Hematite/[Hematite + Goethite]) and the ratio calculated from the proposed method confirms the representativeness of the results. The study advances soil mapping and land management by providing a robust methodology for detecting soil minerals using remotely sensed data, crucial for agriculture and wetlands. It underscores the importance of integrating field data with satellite imagery for accurate soil analysis across diverse environments.