6 Conclusion
This study took Yan’an as the research object, and evaluated the effects and existing problems of soil conservation in different regions since the implementation of the GFG. By constructing the SCP model and exploring the relationship between the GFG investment and the SCE in some counties, the causes of problems were analyzed. On this basis, suggestions were made for the implementation of GFG in the future. The conclusions of the study are as follows.
(1) Since the implementation of GFG, soil erosion in Yan’an has been effectively controlled. Especially in regions with serious soil erosion, the SCE is more significant. However, due to insufficient theoretical research in the early stage, the implementation of the policy appears blind. The imbalance of input and output in some areas leads to the failure of soil conservation to achieve the optimal effect.
(2) As a theoretical innovation, the SCP model not only explains the low efficiency of previous policies but also simulates the investment difference of GFG under the same SCP, thus providing a new idea for the optimization of future GFG.
(3) The SCP for Yan’an in 2015 was calculated by using the SCP model. According to this, three investment levels of GFG were divided, and corresponding optimization schemes were formulated for different levels.
(4) A dynamic circulation for the optimization of the ecological policy is proposed based on the analysis of the relationship among the SCP, the GFG investment.