Lamine Fall A.C.A, Montoroi Jean-Pierre, Starh K. (2014). Coastal acid sulfate soils in the Saloum river basin, Senegal. Soil Research, 52 (7), p. 671-684. ISSN 0371-1897.
Titre du document
Coastal acid sulfate soils in the Saloum river basin, Senegal
Soil Research, 2014,
52 (7), p. 671-684 ISSN 0371-1897
Soils in boundary conditions of contrasting ecosystems generally show unique features. Transition often leads to changes in soil-forming processes, whereby the environment never comes to equilibrium and therefore the soil chemistry and mineralogy show different influences. Such an environment was analysed in the Saloum River basin, west-central Senegal. The objective was to identify the main pedogenic processes prevailing in this saline and acid pedoenvironment and to assess the influence of environmental factors (climate, topography, soil salinity and acidity) on local soil formation and mineral distribution. The terrace landscape is built up by a floodplain, a low terrace, which is still influenced by groundwater, and a middle terrace. The results show that soil properties are strongly influenced by hydrology, salinity and acidity in the entire toposequence: Gleyic Hyposalic and Hypersalic Solonchaks (Sulfatic) in the floodplain, Haplic Gleysols (Thionic) in the low terrace, and Endogleyic Arenosols in the middle terrace. The oxidation of pyrite followed by the redistribution of the main products (Fe2+ and SO4 2–) represents the major chemical process responsible for iron oxide and jarosite formation. Mineral distribution and crystallinity are linked to the landscape position, which controls the hydrological behaviour and reactions of Fe and S ions. Finally, we observed intrapedon processes such as gleysation, sulfidisation and sulfurisation, as well as interpedon processes such as salinisation, colluvio-alluviation and lateral eluviation. The combination of processes depends strongly on the landscape positions.
Plan de classement
Constituants et propriétés des sols [068PROSOL]
Descripteurs
SOL ; CATENA ; ACIDIFICATION ; SALINISATION ; ZONE COTIERE ; PLAINE INONDABLE ; ALTERATION CHIMIQUE ; PEDOGENESE ; ANALYSE MINERALOGIQUE ; FER ; SULFURE ; TOPOGRAPHIE
