4.1 Evaluation of the SCE after the implementation of GFG
As shown in Figure 3, in general, the average annual amount of soil erosion in Yan’an decreased from 4884.49 t·km-2·a-1 in 2000 to 4087.57 t·km-2·a-1 in 2015. This result shows that the effect of GFG on soil conservation is significant. The implementation of GFG has improved the level of vegetation coverage, curbed the increasingly serious soil erosion in Yan’an, and improved the effect of soil conservation.
[Figure 3 near here]
From the spatial perspective, compared with 2000, in 2015, the area with an average annual soil erosion of more than 8000 t·km-2·a-1 almost completely disappeared. The scale of the region between 5000 and 8000 t·km-2·a-1 has been significantly reduced. At the same time, the average annual soil erosion between 2500 and 5000 t·km-2·a-1 increased significantly. The above results show that, since the implementation of GFG, the soil erosion in Yan’an has been significantly reduced on the whole, while the differences between different regions have been gradually narrowed, and some areas with serious soil erosion have achieved remarkable results in the treatment.