The soils of the Mefou Catchment are the typical soils of the southern parts of Cameroon. According to the World Reference Database, the soils might be classified as Ferralosols.
In the local classification system, there a three subtypes of ferralitic soils:
- Red and yellow ferralitic soils cover most of the catchment, especially the mid‐altitudes and the summits. They are deeply weathered (sometimes more than 15 m), have a high clay content and are acidic (pH > 5.5). The main clay minerals are kaolinite, haematite, goethite, quartz and gibbsite. At the foot of the hills the soils are more yellow, also rich in clay minerals (especially quartz) and iron, but less stable than the red soils.
Deep red soils are also known as lateritic soils, because of the presence of an accumulation horizon, containing oxides and hydroxides of iron and aluminium. Agriculture on red or yellow soils is possible after clearing the forest, but due to the low fertility of the soils – most of the nutrients are stored in the biomass – the cultivation system has to take into account the poor soil quality. Besides farming, red soils are used to produce bricks to build traditional houses. They are also a relatively good material for creating unpaved roads.
- Shallower soils are located in areas characterised by high relief and steep slopes. The soils have low humus content and unweathered rocks are close to the surface. These soils are strongly influenced by tree coverage, in that the roots of the trees tend to hold the substratum in place. Due to their topographic position and the shallow depth of these soils they are normally not used for agriculture.
- Hydromorphic ferralitic soils are located In the river valleys. They are of a blackish colour, have higher humus content than the soils higher in the catchment, are therefore more fertile. Yields of plants grown on these hydromorphic soils are much higher than those grown on red or yellow soils. The concentration of sesquioxides (of aluminium and iron) gives the soils a good aggregate stability, which means their susceptibility to being destroyed by raindrops, or to being transported by overland flow, is low. In addition, the high clay content lessens the risk of soil erosion.