Influence of Anthropic and Topographic Factors on the Physicochemical Properties of the Soil around Temporary Pools in Ferlo, North Senegal

The temporary ponds at Ferlo constitute wetlands whose pastoral activity is of paramount importance in the economy of Senegal. These zones are characterized by a fairly specific microclimate (soft and humid), a shallow depth of the water table, alternating phases of submersion and exudation whose functioning is linked to the soil. Thus the restoration and conservation of these wetlands requires a good knowledge of the soil factors.

The objective of this study is to compare the physico-chemical parameters of the soil around temporary pools in grazed and ungrazed areas and different topographical units in order to determine their relative similarities.

The samples taken at different horizons from seven soil pits (P1, P2, P3, P4, P5, P6 and P7) opened in the different morpho-pedological facies of two grazed ponds and one ungrazed pond were analyzed in the laboratory.

The results obtained show that the soils of Ferlo have a sandy texture and low fertility in the slopes and plateaus. However, they have a balanced texture and average fertility in ponds and ungrazed areas. The factorial analysis made it possible to highlight three distinct soil classes. A class of sandy texture soil with very low chemical fertility comes from the plateau. A class of soil with a balanced texture which is rich in cation and calcium exchange capacity found in the low zones of strong mineralization. A last class rich in chemical element with a silty texture which is found in wooded areas.

These results thus reveal the predominant influence of anthropic and topographic factors on the evolution and physico-chemical composition of the soil.