Mineralogy and Structural Organization of a Red to Yellow Soil Sequence in Cuba – Relationships with Soil Properties

Camacho, E.; Robert, M.; Jaunet, A.M.

doi:10.1016/s0166-2481(08)70329-5

Cited by 3 publications

(1 citation statement)

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“…On another scale of microaggregate analysis, the interaction between organic matter and iron and aluminium oxyhydroxides may increase the scattering light for spectra of soil with porous massive structure because this interaction causes a disorganisation in the arrangement (stacking) of the minerals, primarily by the following two mechanisms: (i) binding to the surface of other minerals by their edges, promoting a disorganised stacking of kaolinite, 43,45,46 and (ii) the iron acting as a polycationic ligand for other molecules in the composition and internal organisation of microaggregates, this same concept also applying to gibbsite. 45 In this way, the porosity formed by a disorganisation in the arrangement of the primary minerals results in increased specific surface area and anisotropic reticular zones, increasing the probability of light being absorbed in internal microaggregate pores, as observed by Bänninger et al 40 Thus, with our soil sample collection, sieving of the samples did not prevent the different reflectance intensity of light and or concavity of the spectra, inherent to soils with porous and cohesive macromorphological features.…”

Section: Spectra Related To Soil Structurementioning

confidence: 73%

Visible and near Infrared Spectra of Ferralsols According to Their Structural Features

Oliveira

Brossard

Corazza

et al. 2016

Journal of Near Infrared Spectroscopy

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In soil science, structural features of soils are an important attribute; soils can be characterised by proportional size distribution of aggregates and the pore space between and within those aggregates. The objective of this study was to evaluate the relationship between the visible and near infrared (Vis-NIR) spectra and microaggregates from a collection of Ferralsols. Our dataset consists of 56 spectra from seven soil profiles of kaolinitic and oxidic-gibbsitic Ferralsols. Soils were characterised according to their morphological features: those with a typical porous massive structure and those with a cohesive massive structure. Size distribution of five classes of microaggregate was determined (1000-2000 µm, 500-1000 µm, 250-500 µm, 105-250 µm and <105 µm). From the soil spectra, we determined the CIE (Commission Internationale de l'Eclairage) red index (RI CIE) and the absorption intensities of kaolinite (I Ka) and gibbsite (I Gb). The predominant fraction of microaggregates exhibited sizes between 250 and 1000 µm (F 250-1000). The proportional increase of this microaggregate class in the soils increased the scattering and variability of reflected light, particularly when soil samples showed more than 0.50 g g −1 of F 250-1000. The microaggregate size explained over 55% of reflectance intensity variability of wavelengths in the Vis-NIR regions, principally on reflectance intensity and concavity of the spectra at 436 nm, 546 nm and 2236 nm, which decreases with increased proportion of F 250-1000. Thus, different structural features of Ferralsols can be directly evaluated through Vis-NIR spectroscopy, even in samples sieved through 2.00 mm. These results highlight the potential use of Vis-NIR spectroscopy in studies of soil classification, soil physical behaviour and soil physical fertility and environmental studies, principally by a new method of analysing bulk density and structure of soil directly from the soil spectra, without the need for predictive models. As well as spectra, RI CIE , I Ka and I Gb can be used to characterise the various structural features of Ferralsols.

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Section: Spectra Related To Soil Structurementioning

confidence: 73%