Effects of vegetation restoration on soil conservation and sediment loads in China a critical review

China has been one of the countries suffering from the most serious soil erosion, which has severely degraded soil productivity and water quality, thus affecting agricultural activities and hindering economic and social development. During the past few decades, a large amount of effort has been made to combat soil erosion. Vegetation restoration as a major strategy is given equal importance compared to engineering measures. Although a measure of success has been achieved, many uncertainties remain unanswered such as to what extent the vegetation restoration has reduced soil erosion and sediment loads especially in large river systems. This paper first analyzes the impacts of vegetation restoration on soil erosion and sediment loads in terms of vegetation cover and vegetation species. Then, the spatial scale effect of soil erosion reduction benefit resulting from vegetation restoration is elaborated. Soil erosion reduction benefit decreases with increased vegetation planting area. In addition, a comprehensive discussion about the disputes between vegetation restoration and engineering measures is made by integrating published studies spanning large spatial and temporal scales. Finally, future research needs regarding vegetation restoration efforts are given. In order to evaluate the effects of vegetation restoration programs on soil erosion, assessments in shorter time interval and larger spatial scale should be undertaken. Further, the present assessment system mainly based on simple statistical methods has to be improved. Specific areas demanding immediate attention, including the western China in general and the upper Yangtze River basin in particular, are highlighted as well.