Study On Land Use Change And Ecosystem Service Funcyion Of Smallwatershed In Hilly Gully Region Of Loess Plateau

In recent years,the ecosystem service function and other value quantificationhave been the hot spots in the sustainable development assessment in the world.The in-depth quantitative study of the ecosystem service function can make the human being more aware of the importance of protecting the natural ecosystem,and then better deal with the relationship between human society,economy and ecology?environment and sustainable development.The function of ecosystem services to human beings is usually embodied in two major categories:one is to provide the products and services necessary for human survival and life,such as providing food,medicinal materials,other production,raw materials for life,and so on;and two is the function of guaranteeing the quality of human life,such as some ecosystems.The typical representative area of the Loess Plateau,Nangou small watershed in the Loess Hilly Region,is selected as the research area to evaluate the ecological benefits of land use change and its ecosystem service function under the long-term ecological comprehensive treatment.The relative change of land use?N_C?and the relative change of land use in the vegetation restoration process are adopted in this paper.The corresponding net change rate of land use is used to describe the dynamic changes of land use types in the last 15 ye ars,and to evaluate the improvement of soil fertility quality in the process of regional ecological management with the soil physical and chemical properties under different land use types in the region,and the soil storage in the basin based on RS and GIS technology.Water capacity,soil erosion intensity,and vegetation NPP were estimated,and the distribution information of soil erosion under different terrain factors?slope and slope?was extracted,and the market value method was used to replace the product supply of the ecosystem in the small watershed of South gully,the total value of soil retention,water conservation and carbon fixation and oxygen release service.The results are as follows:?1?The main types of land use in the small watershed of South gully are mainly woodland and grassland.In the 2000-2015 years,the area of the research area garden,the construction land and the forest land are all increased,but the net change of the construction land is the largest,the grassland,the cultivated land and the unused land area decrease,and the net change of the cultivated land is the largest;in 2000-2015 years,about 70%of the land use category in the river basin The conversion rate of the construction land area is relatively large,up to 96.94%,and the transfer rate of other unused and grassland area is equal,reaching 64.25%and 63.34%respectively,mainly from the transfer of cultivated land and woodland.?2?The difference of physical and chemical properties of soil under different land use is obvious.The total nitrogen content of soil in different vegetation types is grassland>woodland>cultivated land>orchard;the soil available potassium in different land use,the content of available phosphorus is gradually decreasing with the increase of soil thickness on the section layer,and the surface layer of different land use soil surface profile.The density of surface?0-30cm?organic carbon was ranked as grassland>woodland>cultivated land>orchard,and the change range of 0-30cm organic carbon density in each land use soil was between 1.39-1.71kg·m^-2.?3?The water storage capacity method was used to estimate the amount of soil water storage in the basin.The results showed that the soil water storage value in the whole basin range was between 229.91³97.26mm,and the average water storage value per unit area was between 1540.42²661.69 and/hm²,and the value of the un it area storage value of four plant types was cultivated land>Garden>grassland>woodland.The total value of water storage is woodland>grassland>Garden>culti vated land.The total water storage value of forest land was 62.58% of the watershed a rea,and that of grassland was 23.66%.?4?A modified universal soil erosion model?RUSLE?was used to analyze the soil erosion and soil retention in the basin and the soil erosion intensity under the effect of different terrain factors was that the soil erosion intensity reached 1841.31t/?km²·a?from the erosion intensity classification,and the soil erosion intensity and invasion were increased with the slope grade.The average soil erosion intensity of different slope directions is the highest in the Zhengyang slope,followed by the semi sunny slope and the half shade slope,and the lowest on the positive slope.The main contribution of different land use and fertilizer conservation function in watershed is forestl and and grassland.The total value of soil and fertilizer conservation of forestland is 2930755.42 yuan,62.58%of basin area is 67.50.The total value of grassland is 1126076.39 yuan.With 21.20%of the basin area,the value of soil consolidation and fertilize rconservation reached 25.94%.?5?Using the CASA model to estimate the results of the vegetation NPP,the average quality fluctuation range of the land use unit area of the southern gully basin is larger than that of 6.047³9.177gC m^-2 A^-1.The order size of the total NPP in different land use is in the order of woodland>grassland>Garden>cultivated land.The value of carbon sequestration and oxygen release was significantly different among different land use types.The total value of carbon sequestration and oxygen release from forestland accounted for 62.58%of the watershed area,and the total value of grassland accounted for 21.20%of the watershed area was reached to 14.81%.?6?Take the market value method and replace the market law to estimate the ecosystem service function value of the river basin.The result shows that the ecosystem service function value of the different land use mode is 5 million 725 thousand and 100 yuan.