Science et changements planétaires / Sécheresse


Analysis of morphopedological units in the Senegal River valley based on remote sensing data Volume 12, issue 1, Mars 2001


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Société nationale d'aménagement et d'exploitation des terres du delta et des vallées du fleuve Sénégal et de la Falémé (SAED), BP 74, Saint-Louis, Sénégal.
  • Page(s) : 7-14
  • Published in: 2001

This study was aimed at analysing organization and changes in soil surface conditions in the middle Senegal River valley on the basis of field and remote sensing data. This research involved a comparison of three sets of information from very different sources: elementary surface conditions (frequency of surface components, microtopography), soils (physiocochemical composition) and reflectance values obtained via field radiomety and from two SPOT scenes recorded in the dry and rainy seasons. Three analytical scales were used (plot of land, landscape segment, landscape). The multivariate analysis of all collected data revealed that: - Senegal River alluvial valley soils differend overall with respect to two constituents (clay and fine sand); topography was the main pedogenesis factor; soil units generally merged with geomorphological units, which clearly differed with respect to soil surface conditions. - In the three analytical scales, seven balance states or processes were were defined, highlighting the involvement of dynamics between four poles: organic accumutation, mineral accumulation, mineral accumulation, soil surface stability and destructuring. - Soil surface conditions were organised according to the different topographical units and variations in spectral responses all matched this organization, indicating that remote sensing data can be used to monitor of landscape transformation.