Soil degradation in the Senegal lower valley
Résumé
The Senegal River is regulated by two dams, the Diama anti-salt dam constructed in 1986, close to the
river mouth (Fig. 1), to prevent marine intrusions during high tides, and the Mantanali reservoir dam
that was impounded two years later in Mali. Since then, there has been a spectacular development of
irrigated agriculture in the valley. The initial plan for development of the Senegal River valley
envisaged a potential of at least 250,000 ha, which could be increased to 375,000 ha, mainly in the
two countries, Senegal and Mauritania. This intensification of agriculture and the increase in irrigated
areas has disrupted the existing environmental balance. It is therefore important to determine whether
they have caused soil degradation, or simply offered a new framework for the development and
exploration of the Senegal middle valley. Impact studies prior to development are generally
insufficient to understand the environment and the complexity of its functioning. As will be shown in
this study, recent pedogenetical processes in the Senegal River valley have led to soil diversity and
salinity distribution. The first objective is to illustrate the mechanisms that dominated this
environment until the commissioning of the two dams. In a second step, we will present the evolution
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of some sites being studied at the beginning of irrigated agriculture, focusing on soil salinisation and
alkalinisation hazards.
Origine : Fichiers produits par l'(les) auteur(s)
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