The CEC (Cation Exchange Capacity) of a soil represents its capacity to retain and exchange nutrient cations with plant roots. In Sudanese modified natural forests, hydromorphic soils are characterised by a silty-clayey texture and a large specific surface area, which enables them to retain cations in a manner that is distinct from sandy soils. It was hypothesised that the CEC of the topsoil in modified natural forests in western Burkina Faso would demonstrate a significant increase as a consequence of the substantial environmental changes that occurred during the fallow period. To test this hypothesis, a comparison was made between the soil fertility of the forests and fallows and that of the cultivated plots, which were selected as witnesses to the increase. A total of 15 plots were selected, with five plots allocated to each situation. The vegetation and soil characteristics of each plot were documented. Soil samples were taken from the 0-20 cm horizon to create composite samples. The laboratory soil analyses included a number of parameters, including texture, pH in water and KCl solutions, carbon, nitrogen, CEC and exchangeable bases. The observations yielded a classification of the soils as tropical ferruginous hydromorphic soils with iron and manganese sexquioxide. The original materials indicate that the soil is predominantly silty-clayey in composition. The granulometric study demonstrated that the soils exhibited a predominantly silty-clayey texture in the surface horizon. This results in a high retention capacity for exchangeable bases. The woody vegetation of the forests is characterised by a greater diversity and richness of flora than that of fallow land. This has a significant impact on the enhancement of the CEC, due to the replenishment of the soil with plant debris of varying organic compositions. The overall pH is slightly acidic, with a value of 5.98 for pH in water (H2O) and 6.41 for pH in soil. Forest soils exhibit elevated concentrations of carbon (1.48% C) and nitrogen (0.1% N) in comparison to fallow soils (0.65% N, 0.05% N) and agricultural fields (0.34% C, 0.03% N). The observation of chemical balances has identified forests as suitable locations for optimal plant nutrition. In general, forests enhance the CEC and exchangeable bases, despite the values remaining below the recommended threshold for tropical ferruginous hydromorphic soils. It is thus imperative to implement strategies that will foster sustainable agricultural practices and enhance agricultural productivity in this region, where soil nutrients are naturally scarce.