| Located in inland arid areas, and having two-thids of China's desert area and approximately 433,000 km2 of sandy desertification land, Xinjiang is the province which has the largest and most widely distributed sandy desertification land and is most seriously harmed by sandy disaster in china,and also it is one of the most serious region of sandy desertification in the world. In many cities and counties of Xinjiang, disastrous weather such as gale, sand storm, sand blowing, sand floating are frequent. Farmlands, grasslands, forests, residential areas, roads and railways often suffer the invasion of sand disaster. Sandy desertification is seriously threatening and restricting Xinjiang's ecological security and development of society and economy, and endangers the environmental quality and sustainable development of society and economy of east China.As a basic research work, sandy desertification preventing and controlling regionalization is of great significance in practice as scientific guidance for desert regions to guard against and control sandy desertification. Since 1980s, Chinese scientific research workers have undertaken a number of researches of this domain or similar domains. Up to now, some researches also have partially involved the sandy desertification preventing and controlling regionalization of Xinjiang, but they are all relatively sketchy, not systematic and not comprehensive. A detailed and specialized regionalization of sandy desertification prevention and control in Xinjiang has not yet been seen.In view of the complexity of geneses of sandy desertification, the diversity of sandy desertification types, the distributional universality of sandy desertification lands, the gravity of sand disasters and the urgency of controlling sandy desertification in Xinjiang, based on scientific analysis of genetic conditions and status quo of sandy desertification and their spatial differentiation law in Xinjiang, using the existing related research results for reference, and through a combination of qualitative and quantitative methods, this thesis proposes a regionalization scheme of sandy desertification prevention and control in Xinjiang.The XinJiang sandy desertification preventing and controlling Regionalization (XJR) uses three-level regionalization systems. In order to link up with the national regionalization of sandy desertification control, the two treatment sub-districts of Xinjiang in the "national anti-desertification planning", only whose names are made necessary adjustments to, are taken as the first level regions in the first level regionalization system of XJR. On this basis, further second level and third level regions are partitioned off.In light of the vastness of Xinjiang and the significant differences in genetic and evolutional conditions of sandy desertification in various geomorphic regions, and for the sake of convenience of outcome application, the thesis marks the second level regions off mainly based on large geomorphic units.On the basis of the second level regions, the third level regions are partitioned off resting on the difference of one or multiple factors such as middling and small physiographical units, causes of sandy desertification, land cover types, conditions of desert vegetation cover, characteristics of wind drift sand activities and situation of sand disasters, difficulty level of sandy desertification control, consistency of countermeasures on sandy desertification and so on. In order to indicate the difference quantitatively or semi-quantitatively and thus to delimit the regions easily and reasonably, after analyzing and comparing the factors, and also taking the availability of data into account, the thesis selects 5 indices as indicators of the third level regionalization system. The 5 indices are sand-dust weather index (produced by reclassifying the composite of annual mean sandstorm days and annual mean sand-blowing days), land cover index (produced by reclassifying the composite of land cover types and landform types), vegetation cover index (generated by grading the value ranges of NDVI), gale index (generated by grading the value ranges of annual mean gale days), and elevation index (produced by grading the value ranges of elevation). Then, under the support of ArcGIS software, these indices are integrated into Sandy Desertification Comprehensive Rating Index (SDCRI) by Weighted Index Summation Model. Lastly, according to the differences of DCRI and those of leading factors in various regions, and considering such subsidiary factors as demarcation lines of physiographical units, boundaries of rainfed vegetation (non-mountainous regions), demarcation lines of county level administrative regionalization units, population density of farmland-residential area (produced by dividing county population by total area of farmland, garden and residential area in a county), and sum of population proportion and farmland-residential area proportion (sum of the proportion which the population of a county accounts for of that of Xinjiang and the proportion which the total area of farmland, garden and residential area of a county accounts for of that of Xinjiang), the third level regionalization units and their boundaries are delineated.After the above-mentioned zoning process, Xinjiang is eventually divided into 2 first level regions, 7 second level regions and 22 third level regions.Finally, the thesis summarizes and proposes suitable biological, non-biological preventing and controlling technologies and 22 special or comprehensive technologies and modes in Xinjiang, and suggests suitable controlling technologies and modes respectively against the status and characteristics of sandy desertification in each third level region. The technologies and modes mainly include land banning, land banning and plant nurturing, planting of farmland shelterbelt, afforestation by water-saving irrigation, intercropping of trees and crops, cropping of characteristic medical plants, and so on.
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