Influence of erosion control afforestation on some soil parameters in two watersheds in Southwest Bulgaria

Soil is limited resource with vital role in maintenance of variety ecosystems. One of the greatest treat for soils is soil erosion. This natural hazard is widely spread in the terrestrial world, and the territory of Bulgaria is also affected.  Important role for soil protection has a forest vegetation and afforestation is widely used for erosion control activity. The main benefits of afforestation are reduction of water runoff, erosion and sedimentation year-round, which is important for the areas located around the reservoirs and their basins. They also decrease the migration of vital substances for soils and sedimentation yield.  The main goal of the study is to establish the influence of erosion control afforestation to the main soil characteristics in the territory of two watershed situated in Southwest Bulgaria. Soil samples and dead leaf cover were analyzed as well as some characteristics of afforestation and topographic charac-teristics. It was established high water resistance of the soil aggregates under the planted forests and low resistance in the controls. The amounts of content of org. carbon and total nitrogen varying with slope and exposure. The differences between parameters of soils under afforestation and in control samples is established which shows an important influence of forest to the soil characteristics.