@article{fdi:010014389,
  title = {{T}he alkali soils of the middle {N}iger valley : origins, formation and present evolution},
  author = {{B}arbi{\'e}ro, {L}aurent and {V}an {V}liet-{L}anoe, {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n {N}iger {R}epublic, the regional development of irrigation along the river {N}iger is confronted with a large extent of alkali soils. {F}or a sound management of the irrigated area, it appears necessary to understand the present evolution of these alkali soils. {T}he study of one of these areas, located on the {L}iptako bedrock, reveals a concentric soil distribution : within a zone of brown soil with abrupt textural change and alkaline in depth (stagnic {S}olonetz), appears a ring of brown steppe soils (cambic {C}alcisol), around zones of alkali soils ({S}olonetz). {T}hese alkali soils are not saline but their soil solution is more concentrated than in brown steppe soils. {T}he abrupt boundary between the brown steppe soils and the alkali soils is related with morphological and geochemical changes, resulting from calcite and fluorite precipitation in the soil solution. {T}he detailed study of this contact demonstrates the current transformation of alkali soils into brown steppe soils. {T}herefore, it appears that soil alkalization is no longer in process on the terraces of the river {N}iger. {T}he formation of brown steppe soils and alkali soils may be explained by the juxtaposition of two contrasted hydrological regimes in a former pond. {T}his hypothesis is supported by aerial pictures and microscopic observations. {I}t is also consistent with a recent study of the hydrology of {S}ahelian ponds and with considerations on the chemical quality of the runoff. ({R}{\'e}sum{\'e} d'auteur)},
  keywords = {{TOPOSEQUENCE} ; {SOL} ; {CARACTERE} {MORPHOLOGIQUE} ; {CARACTERISTIQUE} {CHIMIQUE} ; {DIFFERENTIATION} {PEDOGENETIQUE} ; {ALCALINISATION} ; {NIGER} ; {NIGER} {VALLEE} {MOYENNE}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {84},
  numero = {4},
  pages = {323--343},
  ISSN = {0016-7061},
  year = {1998},
  DOI = {10.1016/{S}0016-7061(98)00003-2},
  URL = {https://www.documentation.ird.fr/hor/fdi:010014389},
}