Evaluation Of Ecological Restoration In Loess Hilly Gully Region Based On Biomass

The biomass of vegetation is an important parameter of vegetation growth condition,which is also an important means to evaluate the regional restoration of vegetation.The restoration of vegetation is a direct reflection of the regional ecological restoration,therefore,it is feasible to evaluate regional ecological restoration based on the biomass of vegetation.This paper studies the eight typical small watershed areas in pengyang county of Ningxia,the second sub-section of the loess hilly region,the data is based on high-resolution remote sensing images in 2005 and 2014,applied with RS and GIS technology,with the aid of software R,GAM model,spatial analysis to evaluate the ecological restoration of the small watershed by biomass of vegetation.First,through visual interpretation of 2005 and 2014 high-resolution remote sensing images,the author gets the two-year first class status data of land use classification of small watershed.Under the platform of ArcGIS,the author analyzes the changes of land use in the small and small river basins of different ecological zones.Second,in application of the ENVI,by getting the vegetation index was extracted from the various watershed,regression analysis is carried out by the field survey data and the normalized vegetation index,the biomass estimation model of vegetation floor was established to estimate the biomass of the soil in the small watershed,the changes of biomass in vegetation were analyzed,the changes of biomass of vegetation in different ecological zones were obtained.Finally,according to the characteristics of the small river basin itself,the terrain analysis and superposition analysis are used in ArcGIS software,extracting the terrain factors such as elevation,slope and aspect,with the aid of R software,the GAM model is constructed from the terrain factor and the field research in 2014,to analyze the relationship between biomass and topography of vegetation,through spatial analysis,geostatistics,etc in ArcGIS,to make a map of the biomass space of grass ground,the spatial distribution of biomass in the vegetation of different watershed is analyzed,and according to different ecological restoration measures of different watershed,and different water and soil conservation methods,to analyze the relationship between biomass and ecological restoration of vegetation.The research begins with the land use/collapse,the changes of vegetation cover in the small watershed are analyzed,using NDVI to estimate the biomass of vegetation on the small river basin,show its spatial distribution,finally,by studying the relationship between biomass and topographic factors and ecological recovery measures,the author analyzes the ecological restoration of the small watershed so as to provide support for the restoration of vegetation,soil and water conservation,and ecological restoration.Some conclusions can be drawn as follows:(1)The aspect of Land use change in small watershed,some changes have occurred obviously in the land use/fall in 8 typical small river basins of Pengyang county.To be more specific,the area of cultivated land has decreased significantly,the area of grassland and woodland has increased.For small watershed in different ecological zones,the different geographical position,natural environment cause the difference ofthe ecological restoration model,and make the differences of land use change of the valley.In the area of anjiachuan,which is located in the northern hills and gullies,the cultivated land has been greatly decreased while the forest area has increased at most.This area is filled with ravines,traditional cultivation mode is not only inefficient,but also easily causing soil erosion,and thus returning farmland to forest and terrance project are the main approach to restore the zonal ecology.Located in the Midwest platform in the rainfed agricultural reserve ditch,fort gao jian,wang 1i gully watershed,this area is relatively flat terrain,along with the increase of the grassland area,according to the regional characteristics,gao jian JingGuoLin fort valley planting area park area increased.When the river basin is governed,more and more irrigation is used,and the area of woodland is transformed into grassland.Residual tableland is located in the south valley farming area after a great ditch,ditch,Ruhe basin,affected by ecological resettlement,town village area is increasing,while industrial and mining land and unused land and other land area is significantly decreasing.Located in the southwest of honghe river basin forest headwater,Liupan Mountains,sufficient water,soil water content is higher,more appropriate for tree growing,such as forest land area is significantly increasing.(2)The aspect of biomass changes in shrub grassland in small watershed,the biomass of eight small watershed vegetation in pengyang county has increased significantly.8 the typical small watershed in pengyang county,bringing the ground biomass are significantly increasing,the ground vegetation biomass growth is more outstanding is gao jian,fort river valley,the king,a great valley,the growth rate is respectively 48.87%,38.35%,48.87%.The area with the smallest increase of biomass of vegetation was the red river basin and the latter valley,with a rise of 7.49%and 8.92%.It shows that the vegetation restoration of pengyang county was better in 10 years,and the vegetation coverage of four ecological zones increased.Among which,the Midwestern rain fed agricultural area stands the best in the vegetation restoration degree,in the implementation of the "88542",levels of measures,such as vegetation habitat get effective protection.In the northern hills and ravines and soil erosion areas,the natural environment is relatively vulnerable,and the vegetation biomass has increased under the implementation of ecological restoration measures.Residual protection the south valley farming area,southwest headwater forest vegetation aboveground biomass growth is small,but the soil moisture conditions are relatively good,vegetation coverage foundation is better,in the implementation of the ecological recovery measures and vegetation habitat is further protection,vegetation aboveground biomass has also increased.(3)Using high-resolution remote sensing images,the vegetation index(NDVI)was extracted from eight small watershed areas of four different ecological zones in 2005 and 2014 respectively.In this paper,the regression model is established by establishing the regression model for the two phase image NDVI values,establishing the transformation equation SPOTNDVI = 0.8983 ZY-3NDVI + 0.0598(R2 = 0.805),reducing the difference between different sensor remote sensing images and the difference between the parameters of the calibration parameters,and the data of the biomass of the vegetation on different watershed are estimated.(4)The correlation between biomass and topographic factors in the irrigation area of the small watershed is obvious,and the distribution of biomass on the soil is differentiated in the slope,elevation and slope.The vegetation was more distributed in the eastern slope between 1470-1620m and 1750-1840m,and the vegetation was better.In the south and north slope between 1620-1750,the vegetation was less distributed and the vegetation was relatively poor.It also reflects the changes in the light,water,heat and other elements needed for vegetation growth to further influence the growth of vegetation.(5)The small watershed of shrub grassland biomass in 2014 was higher than that in 2005,the spatial distribution characteristics of small watershed shrub grass biomass has closed contact with land use,the land use decided the distribution of shrub grassland biomass.Forest Aboveground biomass was the highest,followed by grassland,arable land.The small watershed land use was effective,forestland and grassland has increased,vegetation coverage increased obviously,the ecological environment has been greatly improved,the ecological restoration measures have a good effect of small watershed ecological restoration.