The spatial variability of erodibility and its relation to soil types: a study from northern Ghana

In many parts of Africa, where regional mapping of soil erosion risk or related land-use planning exercises take place, existing soil maps are the only sources of information available when estimating erodibility. The current study examines the spatial variability of erodibility and the extent to which it is related to soil types based on a case study from northern Ghana. Soil samples from 136 test sites were analysed to determine erodibility parameters and surface characteristics were described in the field. Through ANOVA analysis, the intraclass correlations and within-class variations related to soil types were examined which showed an overall poor relationship. The fraction of sand was found to be the best indicator of erodibility due to its low spatial heterogeneity and determined the friability of water-stable aggregates. Further studies investigating the uncertainty associated with the use of soil maps in erosion studies should be carried out with the aim of producing soil maps with statistical information relevant for land resource studies.