| Study on land ecological security has become a leading subject of the sustainable use of land resources, but until now it is still in its infancy. Most Farms of the Xinjiang Production and Construction Corps (hereafter be shorted as XPCC) are located in transitional zone from desert to oasis which is adjoins desert; as a result, its natural ecological environment becomes very fragile. There, irrational use of agricultural land has led to desertification, soil erosion, salinization and other problems which poses a grave threat to ecological security. How to sustain the development of land resources turns to be a worrying issue at present. Hereby proposes measure to optimize agricultural land use from the view of ecological security. By this, we can not only get a clear understanding and evaluation on the ecological security of agricultural land in XPCC, but also we can find a way to improve patterns of agricultural land use, to protect agricultural land resources and to coordinate relationship between human and land. Therefore, this research will plays a practical and significant role for the sustainable development of the society and economy in XPCC. In addition, this research will provide references for the use and optimization of agricultural land in those arid areas.This paper consists of eight chapters:chapter reviews research progress of domestic and foreign agricultural land use and ecological security assessment, and comments on these research at home and abroad; chapterâ…¡makes a summary of theoretic tools for research, defines the concepts in the research; partâ…¢sorts out and analyzes agricultural land utilization Since the founding of the XPCC; chapterâ…£establishes agricultural land ecological security assessment index system based on the emergy-based improved ecological footprint theory, and evaluates the ecological security of agricultural land use from 1982 to 2008 in XPCC from time scale and space scale; Chapterâ…¤identifies impact factors of ecological safety of agricultural land use, and analysises mechanism of influence of each factor; chapterâ…¥constructs early warning systems of ecological safety of agricultural land use and makes an empirical research on ecological safety of agricultural land use based on the Punishing Variable Weight; chapterâ…¦makes optimization of agricultural land use based on the perspective of ecological safety, and Proposes specific Optimization measures; chapterâ…§reaches the conclusions and deficiencies for whole thesis.The main conclusions draws from this research are as follows:â… . In the period from 1982 to 2008, the changes of agricultural land use in XPCC are as follows:in the quantity of agricultural land use, the quantity of the total area of agricultural land, arable land,pasture, woodland and garden tended to be from rapid increase to slower increase. While, the area of aquaculture water had little change due to its small amount; in the quality of agricultural land use, agricultural land use showed a trend of flat to down, among which, the proportion and amount of high-yielding land area decreased, the proportion and amount of medium-yielding land area increased, the proportion and amount of low-yielding land also decreased; in the rate of the change extent of agricultural land use, the rate of the change extent of agricultural land use was R=-0.166, which told us the agricultural land use in XPCC was just in the period of adjustment. in the efficiency of agricultural land use, the efficiency of agricultural land use in XPCC presented a tendency of down to up, it still has potential space to up; in the intensity of agricultural land use, the intensity of land use tended generally to increase during fluctuation.â…¡.The conclusions of the evaluation of ecological footprint and ecological security for agricultural land use in XPCC from the time scale are as follows:from the year 1982 to the year 2008, the total ecological footprint and per capita ecological footprint of agricultural land had a upward trend, but the total ecological bearing capacity and per capita ecological bearing capacity first increased and then decreased. The ecological safety level of agricultural land turned to increase at first and then decrease as well. Taking the year 1998 as boundary, before 1998 the safety level showed a rising trend and the ecological coordinative degree was in harmonious. After 1998, the safety level declined from a little insecurity (â…¡b) to less security (â…¢a), eventually to the total insecurity in 2008 (â…¢b). At the same time, the ecological coordinative degree declined from harmonious state to close coordination with the basic coordination of the boundary value (1.1371).â…¢.The conclusions of the evaluation of ecological footprint and ecological security for agricultural land use in. XPCC from the space scale are as follows:in the year 2008, the per capita ecological footprint of agricultural land of 13 agricultural divisions in XPCC increased compared with that of 1982. Except Division 13 and Division 14, per capita ecological bearing capacity of other 11 divisions increased. While, the ecological safety level of Division 14 decreased, from the very safe (â… a) down to safer (â… c);the ecological safety level of Division 1, Division 4, Division 6 and, Division 8, Division 9, Division 12 and Division 13 kept stable, the ecological safety level of Division 2, Division 3, Division 5, Division 7 and Division 10 turned to be increased.â…£.The conclusions of the early-warning on ecological security based on the Punishing Variable Weight angle are as follows:in the period of 1982-2008, the ecological safety index of agricultural land use has increased at first and then shows a downward trend, which still belongs to Light-Alert interval, in the period of 2009-2015, the ecological safety index of agricultural land use would be more degraded to some extent in 2008 and remain at the Light-Alert interval, and the extension to down to the Medium-Alert interval; from early-warning subsystem point of view, in the period of 1982-2008,the ecological safety index of Water use subsystem and of population subsystem show a rising trend, in the period of 2009-2015,it would be remain at the No-Alert interval; in the period of 1982-2008, the ecological safety index of the subsystem of agricultural land development has increased at first and then shows a downward trend, which still belongs to Light-Alert interval, in the period of 2009-2015,it would be remain downward trend, and the extension to down to the Medium-Alert interval; in the period of 1982-2008, the ecological safety index of agricultural planting structure subsystem show a downward trend in the overall, and has dropped from No-Alert interval in 1982 to Light-Alert interval in 2008. in the period of 2009-2015,it would be remain downward trend, and the extension to down to the Medium-Alert interval.â…¤.The conclusions of the Optimization of agricultural land use based on ecological security are as follows:In agricultural land use structure optimization, compared with the date in the year 2008, except that the area of pasture and water has remained unchanged, the area of arable land has decreased and the area of garden and woodland has increased. from the results of ecological security of optimized agricultural land use structure point of view, the level of ecological safety of optimized agricultural land would be increase from insecurity (â…¢b) to little security(â…¡a),and benefits of ecological and economic is far greater than predicted; The result of optimization of arable land utilization illustrates that the area of food crop has remained stable, the area of cotton, oilseed and vegetable has deduced to some extent, the area of fruits has been on the contrary. The result of optimization of pasture utilization demonstrates that the ecological bearing capacity of Division 1, Division 3, Division 6, Division 7 and Division 8 has already overloaded. In order to protect pasture and conserve its security, they should take various kinds of measures, such as prohibiting grazing by fencing, rest-grazing, rotational grazing, and so on.
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