Study On Soil Conservation And Carbon Sequestration Of The Grain For Green Program And Its Influencing Factors In The Hilly Red Soil Region Of Southern China

The Grain for Green Program(GFGP)is the largest ecological restoration plan in China.After 20 years of construction,the GFGP produced huge ecological benefits.Therefore,evaluating the effect of GFGP from the perspective of ecosystem services is of guiding significance for the consolidation and continued implementation of the project in the future.At present,most studies about the ecosystem services of GFGP did not distinguish between the GFGP area and the non-GFGP area.The results hardly highlight the impact on ecosystem services of GFGP.Identifying the GFGP area,and assessing the changes in ecosystem services in the GFGP area will be more conducive for managers to grasp the impact of GFGP on various ecosystem services.In addition,it is of great significance for managers to optimize management measures to explore the trade-off or synergy between various ecosystem services of GFGP and clarify the law of the effects of various influencing factors on the spatial relationships.Therefore,we select the hilly red soil region(HRSR)of southern China as the research object in this study.This study mainly explored soil conservation and carbon sequestration.The GFGP region was identified by land use data from 2000 to 2015 in HRSR.Then,the Change of soil conservation service and carbon storage service in the HRSR during 2000-2015 were evaluated by Revised Universal Soil Loss Equation(RUSLE)and Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST)model.Finally,we analyze the spatial correlation between the relationship of soil conservation service and carbon storage service in GFGP of HRSR by the geographically weighted logistic regression(GWLR).(1)The area of Grain for Green Program(GFGP)in hilly red soil region(HRSR)of southern China is expanding continuously,but the growth rate is slow.Based on the land use,a total area of GFGP was identified in the red soil hilly region of southern China is about 2,052.61km~2.The area of grassland being returned to forest land is the largest,accounting for about 69%of the total area.The implementation of the GFGP showed a trend of expansion from east to west.(2)The benefit of soil conservation was improved significantly overall,but there were still some negative benefits in some areas in the region of Grain for Green Program(GFGP)in the hilly red soil region(HRSR)southern China.From 2000 to 2015,the total soil conservation in the GFGP in HRSR increased by 9.18(?)10~8 t,and soil conservation per unit area increased by447 327.54 t/km~2.Among the types of land use change,the soil conservation benefit of the transform from bare land to forest land is the most significant.The contribution of this transformation type is 3 989 647.43 t/km~2.(3)The implement of the Grain for Green Program(GFGP)in the hilly red soil region(HRSR)of southern China is helpful to enhance carbon sequestration services,and had a positive impact on the mitigation of regional climate warming.From 2000 to 2015,the carbon storage increased by 3.04 Tg C in the region of GFGP in HRSR,and the carbon storage per unit area increased by 0.0015 Tg C/km2.The regions with the most significant carbon sequestration benefits are the central Hunan Province,while the regions with longer implementation time such as Zhejiang and Fujian have relatively low carbon sequestration benefits.Comparison of carbon storage changes of five land use change types related to the GFGP showed that bare land afforestation was the most beneficial way to increase carbon sequestration benefits.(4)The relationship between soil conservation and carbon storage is different in space,and the key influential factor is average temperature.Moreover,the nature and intensity of the correlation between influence factors(such as topographical factors,meteorological factor and GDP)and the relationship of soil conservation service and carbon storage service change with space.