@article{fdi:010065007,
  title = {{P}rediction of soil organic carbon stock using visible and near infrared reflectance spectroscopy ({VNIRS}) in the field},
  author = {{C}ambou, {A}. and {C}ardinael, {R}. and {K}ouakoua, {E}rnest and {V}illeneuve, {M}anon and {D}urand, {C}. and {B}arth{\`e}s, {B}ernard},
  editor = {},
  language = {{ENG}},
  abstract = {{D}ue to the role of soils in the global carbon cycle, there is increasing demand for data on soil organic carbon ({SOC}) stock, but the conventional determination of {SOC} stock ({SSOC}) is tedious and hardly allows meeting this demand. {V}isible and near infrared diffuse reflectance spectroscopy ({VNIRS}) is a time- and cost-effective approach that has been successfully used for characterizing {SOC} concentration, even in the field. {T}he present study aimed at testing the potential of {VNIRS} for characterizing {SSOC} in the field, from spectra acquired on partially disturbed cores collected using a manual auger (thus not using cylinder sampling except for calibration), at 0–10, 10–20 and 20–30 cm depth in two agroforestry fields in {F}rance. {B}oth fields were on silty {L}uvisols under temperate climate and included tree rows with grass cover, plowed interrows with cereals, and a conventional agricultural plot without trees. {C}onventional determination of {SSOC} involved bulk density measurement (cylinder method) and {SOC} concentration analysis (dry combustion) on the same samples, and was calculated as their product. {VNIR} spectra were acquired using an {ASD} {L}ab{S}pec 2500 spectrophotometer, on the outer side of cores collected using a manual auger, at three points around the place where {SSOC} was determined. {I}n total, 288 samples were studied (144 per field). {C}alibration with partial least squares regression was carried out on the 200 most spectrally representative samples, and validation was performed on the remaining samples. {C}onsidering the determination coefficient for validation ({R}2val), standard error of prediction corrected for bias ({SEP}c) and ratio of standard deviation of the validation subset to {SEP}c (denoted {RPD}val), the {VNIRS} prediction of {SOC} concentration was accurate ({R}2val = 0.75; {SEP}c = 1.6 g{C} kg− 1 soil < 2 mm, i.e. 13% of the mean; {RPD}val = 2.0). {T}he prediction of {SSOC} was acceptable ({R}2val = 0.70; {SEP}c = 2.0 g{C} dm− 3, representing 13% of the mean; {RPD}val = 1.8). {P}art of the {VNIRS} prediction error could be attributed to the fact that conventional and spectral measurements were not made on the same samples. {S}canning the cylinder cores would probably result in better {VNIRS} predictions but is not consistent with the objective of determining {SSOC} without tedious cylinder sampling (except for calibration). {H}owever, conventional determination of {SOC} concentration on auger cores (rather than on cylinder cores) could be a valuable solution for improving calibration, with the perspective to develop a rapid procedure for accurate {VNIRS} prediction of {SOC} stock in the field.},
  keywords = {{FRANCE}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {261},
  numero = {},
  pages = {151--159},
  ISSN = {0016-7061},
  year = {2016},
  DOI = {10.1016/j.geoderma.2015.07.007},
  URL = {https://www.documentation.ird.fr/hor/fdi:010065007},
}