@article{fdi:010067290,
  title = {{V}isible and near infrared spectra of {F}erralsols according to their structural features},
  author = {{O}liveira, {J}.{F}. de and {B}rossard, {M}ichel and {C}orazza, {E}.{J}. and {M}archão, {R}.{L}. and {G}uimarães, {M}. de {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n 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. {T}he objective of this study was to evaluate the relationship between the visible and near infrared ({V}is–{NIR}) spectra and microaggregates from a collection of {F}erralsols. {O}ur dataset consists of 56 spectra from seven soil profiles of kaolinitic and oxidic-gibbsitic {F}erralsols. {S}oils were characterised according to their morphological features: those with a typical porous massive structure and those with a cohesive massive structure. {S}ize distribution of five classes of microaggregate was determined (1000–2000 µm, 500–1000 µm, 250–500 µm, 105–250 µm and <105–µm). {F}rom the soil spectra, we determined the {CIE} ({C}ommission {I}nternationale de l'Éclairage) red index ({RICIE}) and the absorption intensities of kaolinite ({IK}a) and gibbsite ({IG}b). {T}he predominant fraction of microaggregates exhibited sizes between 250 and 1000µm (Φ250–1000). {T}he 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 Φ250–1000. {T}he 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 Φ250–1000. {T}hus, different structural features of {F}erralsols can be directly evaluated through {V}is–{NIR} spectroscopy, even in samples sieved through 2.00 mm. {T}hese results highlight the potential use of {V}is–{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. {A}s well as spectra, {RICIE},{IK}a and {IG}b can be used to characterise the different structural features of {F}erralsols.},
  keywords = {{STRUCTURE} {DU} {SOL} ; {SPECTROSCOPIE} ; {REFLECTANCE} ; {MINERALOGIE} ; {AGREGAT} ; {MICROMORPHOLOGIE} ; {BRESIL}},
  booktitle = {{N}ear infrared spectroscopy of soils},
  journal = {{J}ournal of {N}ear {I}nfrared {S}pectroscopy},
  volume = {24},
  numero = {3},
  pages = {243--254},
  ISSN = {0967-0335},
  year = {2016},
  DOI = {10.1255/jnirs.1202},
  URL = {https://www.documentation.ird.fr/hor/fdi:010067290},
}