Extraction And Application Of Soil Line And Residue Line In The Loess Plateau

As the most important level in the vertical structure of the vegetation community,residues play a leading role in the prevention of soil erosion due to the direct coverage of the surface.The main purpose of this paper is to extract the soil line and residue line,studying the discrimination between soil and residue to further improve the accuracy of residue estimation using remote sensing method,which is of great significance for the accurate evaluation of the corrosion effect of residues.In this paper,making the laboratory measured spectral reflectance of soil and residue as the source data,soil line and residue line was extracted in multispectral and hyperspectral space,and the discrimination between soil and residue in specific bands was also discussed.Then the best vegetation index was selected and the residue coverage was evaluated using remote sensing image.Finally,the applicability of all kinds of vegetation index to evaluate residue coverage was discussed from which the most suitable vegetation index was found.The achievements of this paper as follows:(1)Soil line and residue line in multispectral and hyperspectral spaces exist or not was discussed based on the laboratory measured spectral.The result shows that,there exist obvious soil line and residue line in multispectral and hyperspectral space,even the soil line and residue line in hyperspectral space which is made of short wave infrared bands are more obvious than in multispectral space.(2)Based on the relationship between soil line and residue line,the discrimination between soil and residue was analyzed from two aspects of qualitative and quantitative.The results show that,for multispectral space,the best space is made of OLI6 and OLI7 bands,and the best multispectral vegetation index is NDTI and MSACRI.For hyperspectral index,SINDRI is the best two-dimensional vegetation index,and LCA is the best three-dimensional vegetation index.(3)Based on the above research,the best vegetation index NDTI and MSACRI was selected to evaluate residue coverage,and all vegetation indexes was compared and analyzed to find the most suitable one.The results shows that,the correlation between the test residue cover and the measured residue cover based on NDTI and MSACRI was respectively 0.800 and 0.8001,which indicate that NDTI and MSACRI can better discriminate soil and residue.However,for the Loess Plateau with low residue coverage,MSACRI can better resist the influence of soil noise,and its sensitivity to different vegetation types was higher,which is the most suitable senescent vegetation index.