@article{fdi:010015430,
  title = {{F}ield study and simulation of geochemical mechanism of soil alkalinization in the sahelian zone of {N}iger},
  author = {{M}arlet, {S}. and {V}alles, {V}. and {B}arbi{\'e}ro, {L}aurent},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n some soils of the {N}iger valley, alkalinization and sodization are related to the concentration of alteration products of calco-alkaline gneiss to biotite, which releases significant amounts of cations and alkalinity. {T}he results is an oversaturation of the soil solution with respect to calcite, which precipitates with a positive calcite residual alkalinity. {C}a2+ molality decreases, while alkalinity and p{H} increases : {C}a2+ desorption is accompanied by adsorption of {N}a+ on the exchange complex. {K}+, {M}g2+, and {N}a+ concentrations in the soil solution are successively controlled by the formation of illites and smectite-type silicates, while kaolinite dissolves. {T}hese processes were successfully simulated according to the analytical data. {T}hey agreed with the significant increase of the alkaline reserve in the soils according to chemical, physical, and mineralogical alterations. {T}hese geochemical mechanisms were found to be involved in the formation of alkali soils at three sites of the region. ({R}{\'e}sum{\'e} d'auteur)},
  keywords = {{GEOCHIMIE} ; {SOL} ; {SALINITE} ; {ALCALINISATION} ; {SOLUTION} {DU} {SOL} ; {COMPOSITION} {CHIMIQUE} ; {ARGILE} ; {CALCIUM} ; {MAGNESIUM} ; {POTASSIUM} ; {SODIUM} ; {SILICATE} ; {SIMULATION} ; {NIGER} ; {ZONE} {SAHELIENNE} ; {LOSSA} {REGION}},
  booktitle = {},
  journal = {{A}rid {S}oil {R}esearch and {R}ehabilitation},
  volume = {10},
  numero = {3},
  pages = {243--256},
  ISSN = {0890-3069},
  year = {1996},
  URL = {https://www.documentation.ird.fr/hor/fdi:010015430},
}