| Aiming at theoretical problems and key technology needed by effect evaluation research of regional soil and water conservation on ecological environment, this paper studied remote sensing evaluation index of regional vegetation effect on soil and water conservation, information extraction and integration of regional vegetation from remote sensed data, and so on, using the method of remote sensing together with GIS, based on the principle of science of soil and water conservation, biology, geography, and remote sensing. The results of this study is below:1.We analyzed the relation among remote sensing information, vegetation indices, the leaf index (LAI), vegetation vertical structure, and vegetation effect on soil and water conservation, then put forward the principle and reason for evaluation index of vegetation effect on soil and water conservation. At last, we ascertained the remote sensing evaluation indices of regional vegetation effect on soil and water conservation.Firstly, we analyzed the import-influencing factor of regional vegetation effect on soil and water conservation. We found the vegetation coverage and vertical structures are the two most import-influencing factors. The vegetation cover ratio that is the common evaluation index is short of revealing difference of the vegetation vertical structures. It isn't suitable for development in mechanism research. But LAI has good correlation with vegetation coverage and vegetation vertical structures. LAI also has many advantages. It is quantitative, easy to indirectly get from remote sensing data, more comprehensive, simple, practical, and so on. So we chose LAI as the evaluation index of regional vegetation effect on soil and water conservationThe wave band of visible light mainly reveals vegetation coverage. The wave band of near infrared mainly reveals vegetation vertical structures. The vegetation indices, which make up mainly of the wave band of visible light and near infrared, should include information of vegetation coverage and vertical structures. The existing research achievements show that there is a good correlation between the vegetation indices and LAI. Then we think there is a information link from remote sensing data to the vegetation indices, LAI, vegetation coverage and vertical structures, and to vegetation effect on soil and water conservation. So the vegetation indices indirectly detect the vegetation effect on soil and water conservation. In this research, we call the vegetation indices as the indicator of vegetation effect on soil and water conservation, and chose them as the remote sensing evaluation index of regional vegetation effect on soil and water conservation.2.After image process of AVHRR and TM data, We made a remote sensing data set on the same integration platform (GIS) for advanced analysis and evaluation of vegetation effect onsoil and water conservation, then we extracted indicator data of different sensors, different times, and different types, of vegetation effect on soil and water conservation.We have extracted three vegetation indices of RVI (Ratio Vegetation Index) , DVI (Differential Vegetation Index) and NDVI (Normalized Difference Vegetation Index) as the indicators of vegetation effect on soil and water conservation from NOAA and TM images, which has been pretreated and accurately calibrated beforehand. As for countrywide, we made 12 mosaic countrywide images without cloud, from NOAA images, for three years each with four seasons, from 1997 to 1999, as our basic data for the next work. We can easily extract these three vegetation indices in any season of these three years and in any part of allover china. As for sample area, we chose four in china. One is in the northeast, one in the northwest, one in the border of Sichuan and Guizhou province, the last on in the northwest of Guangxi. Among them, the area of the smallest sample area is 17368.46 km2. We extracted these three vegetation indices as the indicator of the index of vegetation effect on soil and water conser...
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