Study On The Temporal And Spatial Changes And The Driving Factors Of The Cultivated Land In Zhangye Oasis

The land is the root of everything. The cultivated land, one type of the land use, is the basic resource of the agriculture. The studies on them have a long history, and the contents of the research ceaselessly change with the advancement of society and the development of productivity. Since the 1990s, the booming of the global change research makes land use and land cover (LUCC) turn into the hotspots of the international researches. LUCC contains lots of matters, and the key one of them is the driving factors of land use change and their action mechanism. The cultivated land is one main type of the land, its use change driving factors and their action mechanism accordingly become important composing portions of LUCC. At present, the many studies on the cultivated land that contain a great deal of the aspects are developed internationally. In China, the correlative researches on the cultivated land are concentrated on the eastern and the middle regions, with a late start there is few achievements obtained in the vast west. According to the above analysis, taking Zhangye Oasis located in the northwest continental river valley of China as a case study, choosing its cultivated land as the research object, analyzing the driving factors of its cultivated land change, the thesis can offer a scientific guide and reference to the: reasonable use of the cultivated land in the northwest regions. The thesis consists six pans.In the first part, the author illuminates the study background, and simply expatiates the research evolution of the land and the cultivated land. In addition, the significance, contents and means of the study are dissertated.In the second part, the author analyzes the temporal and spatial changes of the land use in Zhangye Oasis, which is the research background of the latter study on the cultivated land. First, the author expounds the natural environment of Zhangye Oasis from some aspects such as the location, the acreage, the terrain, the climate, the water resources, the vegetations, and the soils. Second, the social environment is explained by means of depicting the population, the nation, GDP, the industry production value, and the agricultural conditions. Third, the exploitation history of the land is illustrated chronologically, which shows that the land exploitation and the land use transform with the subrogation of the dynasties and the progress of the social productivity. In the end, according to data, the changing trend and patterns of the modern land use are described.In the third part, the temporal and spatial changes of the cultivated land in Zhangye Oasis are analyzed. The author discusses the cultivated land status quo and the existingproblems on the grounds of the verified range of the cultivated land in Zhangye Oasis. Based on the statistical data from 1949 to 2001, the changes of the cultivated land and the cultivated land per capita in Zhangye Oasis are analyzed wholly and partially. The author considers that the quality of the cultivated land will be difficult to be recovered in the short period once having been damaged. By calculating the relative change ratio of the cultivated land, the author analyzes the difference of the cultivated land changes in the different sections of Zhangye Oasis.In the fourth part, the driving factors of the cultivated land change are studied in Zhangye Oasis. From both the natural and the human angles, the effect modes of the manifold factors on the cultivated land change in Zhangye are analyzed qualitatively and quantitatively, amd the results show that the cultivated land change is mainly confined by the use degree of the water resource. The principal component analysis (PCA) is used to study the socioeconomic factors. First of all, the concerned effect factors are filtrated by the special principles. Secondly, the specific analysis about the socioeconomic factors is carried out in each section of Zhangye Oasis. PCA indicates that the pressure of the society system, the development of the dynamic economy and the progress of the...