Erodibility of Cultivated Soils in the Foumbot Area (West Cameroon)

Agricultural lands in Western highlands of Cameroon are likely to face severe erosion because of the interactions of the following factors: high intensity of agricultural activities, poor farming practices and high rainfall intensity. However, the severity of this soil erosion can vary significantly with the ease with which soil is detached and transported by erosion agents. That is why a study was carried out in the Foumbot area in order to evaluate the soil erosion risk variation with some soil types. Thirty one soil samples were collected at 0–20 cm depth from three main soil types encountered in the area (Andosols, Acrisols and Ferralsols). Soil samples were analyzed for particle size distribution (Total clay, Total silt, Water dispersible clay, Water dispersible silt), Soil organic matter, Soil reaction, CEC, Exchangeable bases, clay dispersion ratio, dispersion ratio, clay aggregation and Mean weight diameter). Soil erodibility indicators were determined and used to estimate soil erosion risk for the three soil types. The results showed high dispersive potential of the three soil types. Soil characteristics and the deriving soil erodibility vary from one soil type to another. The most vulnerable soils are the Acrisols and the less erodible are the Andosols. Soil mineralogy seems to be the key factor regulating soil erodibility variation in the area. The Water-Dispersible Silt (WDS) correlates positively with the Soil organic matter (r=+0.67, p=0.000). The Water-Dispersible Clay (WDC) significantly correlates negatively with the soil organic matter (r=-0.61, p=0.000). WDC also showed significant negative correlation with calcium (r=-0.67, p=0.016) and potassium (r=-0.74, p=0.000). Based on its strong correlation with erodibility parameters, soil organic matter content appeared as the main soil characteristic through which soil conservation measures could easily be implemented in the studied area.