Biological measures for soil and water conservation work by their protective impact on the vegetation cover. A dense vegetation cover
These effects entail a low soil erosionrate compared with an uncovered soil which shows in general a high soil erosion rate. Even cultivated crops in agricultural areas are a better protection against soil loss than uncovered soil (relatively high soil erosion rate) . Other positive impacts have been observed, such as improved soil moisture condition (or protection against erosion by wind).
Several types of biological soil and water conservation measures exist (see figure).
Afforestation is presented on the following page.