Since 1980, a series of programs to control soil and water loss have been initiated. These programs have included optimizing the land use structure and configuration, terracing slopes, converting slope cropland into forest and grassland, enclosing hillsides to remove grazing, building reservoirs, and improving basic farmland practices (Yang, 2003).
In 1999, an ecological rehabilitation project called the “Grain-to-Green” Project was extensively implemented on the Loess Plateau. Many infrastructure reforms and ecological projects were undertaken, including the construction of large reservoirs and silt dams, afforestation, converting cropland on steep slopes to forest and grassland, and restoring biological soil crust (BSC) (Xin et al., 2008; Zhao et al., 2010).
Positive effects for soil stability against erosion have been achieved through the recovery of the natural vegetation and the protection of BSC development by increasing the threshold friction velocity and decreasing the sediment yield (Fu et al., 2011; Zhao et al., 2010). BSC covers in grassland rehabilitated after the Grain-to-Green Program, especially in the hilly region, covered up to 60–70% of the soil surface in mature vascular plant communities, and thus played an important ecological role in controlling soil erosion, resulting in a dramatic reduction of runoff and sediment discharge from areas around the middle Yellow River (Chamizo et al., 2012; Zhao et al., 2010)