Land covers after the Grain-to-Green Program have proven to be effective over the last ten years (Fu et al., 2011).
Vegetation cover can lower the land surface erodibility and reduce the risk of soil erosion.
In our study, the trends of the C factor for the whole study area and for each land use (Fig. 8) indicated that the vegetation cover had been largely improved (P b 0.01).
Furthermore, similar to the changes of the soil erosion rates, the declining trend of the C factor for land uses from forest to shrub to woods also increased, and the lower the density of grassland, the greater the decreasing trend of the C factor during the decade. Therefore, vegetation restoration can improve the effectiveness of land cover and reduce susceptibility to soil erosion.
It may also be one of the most important reasons for the decreased rates of soil erosion on
the Loess Plateau and the dramatically decreased sediment discharge from the middle Yellow River since the Grain-to-Green Program.