Study On Degree Of Deterioration Of Bayanbulak Grassland Based On GF-1 Satellite Data

Under the influence of human activities and climate change,on the broke overgrazing grassland area of overload,degradation is very serious,leading to the decrease in the total grassland biomass and productivity has restricted the sustainable development of local animal husbandry.Therefore,it is necessary to judge the degree of grassland degradation,so as to provide a basis for the protection and restoration of grassland resources.Based on our own GF-1 with high resolution satellite for remote sensing image data,using remote sensing technology combined with field investigation,sampling method,through the comprehensive evaluation index,the aboveground biomass of the vegetation and vegetation coverage three indicators combined to judge on the broke grassland degradation degree.The main conclusions are as follows:(1)The result of factor analysis shows that the degree of grassland degradation can be judged by using three indicators of plant height,aboveground biomass,and coverage.The principal component analysis shows that the vegetation coverage is 0.484 and the aboveground biomass is 0.281.The plant height was0.235 and was finally weighted to give GDI.In the study area,GDI has the best correlation with NDVI,and the correlation coefficient is 0.675(P<0.01).On this basis,a comprehensive degradation evaluation model for grassland was constructed.The best inversion model was:y=-0.102x~2+0.776x+0.15(R~2=0.707).The accuracy of the model was high,and its applicability to the study area was good.(2)The correlation analysis between vegetation above-ground biomass and EVI,DVI,NDVI,SAVI and RVI 5 planting indices showed that RVI had the best correlation with above-ground biomass,and the correlation coefficient reached 0.864(P<0.01).The grassland aboveground biomass inversion model constructed using the vegetation index showed that the fitting effect between RVI and aboveground biomass was significantly higher than that of other vegetation indices.The inversion model of the best aboveground biomass was:y=84.106×0.472(R~2=0.851),the model fitting accuracy is 0.904,which can truly reflect the status of ground biomass.(3)The vegetation coverage in the study area was inversed by the pixel dichotomy model,and the vegetation coverage was inverted after determining the parameter threshold.The fitting R~2was 0.813,indicating that the pixel binary model based on the vegetation index NDVI was suitable for vegetation coverage inversion in the study area.(4)By reviewing literature and published knowledge,the degradation degree of Bayanbulak grassland was divided into four grades:no degradation,light degraded,middle degraded,and heavy degraded,and maps of grassland degradation in Bayanbulak grassland were draw;Among them,the light degraded accounted for 48.4%,the middle degraded accounted for 25.7%,and the heavy degraded accounted for12.5%,with no significant degradation of 13.4%.Based on the combination of field conditions and predecessors’research,this study established a research system of degradation evaluation indicators and provided a theoretical basis for the formulation of effective governance measures and targeted governance.