Erodibility of agricultural soils in the semiarid Mediterranean area of Spain

Erosion mapping is a useful tool for soil conservation planning. The possible correlation between soil type or lithology with soil erodibility has been tested with the aim of facilitating the accomplishment of erosion maps from soil or lithology maps. Soil erodibility (K factor of the universal soil loss equation [USLE]) was determined from 340 samples taken from 4 soil types, on which approximately 95% of agriculture in the semiarid Mediterranean area is located. Calcaric regosols (K = 0.47) showed the highest erodibility and are significantly different from the other soil types. It was also possible to differentiate between calcic xerosols (K = 0.41) and petrocalcic xerosols (K = 0.37). No significant differences were established between the other soil types. The statistical analysis of the soil samples, grouped according to lithology, showed a better discrimination than is evident from those grouped as a function of soil type. It was possible to establish significant differences among all lithologies w...