| The grassland resources are important and renewable in our country,which are the basis of the stockbreeding's development. Jilin province as one of our countries'seven large prairie provinces has become one of the most important stockbreeding -produced base,which the existing grassland area is about 60×104hm2. Influenced by natural factors such as the climate and hydrogeology, and human factors such as human unreasonable exploitation, the grassland ecosystem's integrated function has been severely damaged, and so has the grassland, which has blocked the continuous,steady,harmonious development of the grassland stockbreeding -production.Through the interpretation of remote sensing's images and the extraction of the needed data, Jilin's grassland in western for 15 years was researched on space time change. From 1989 to 2004, the total grassland's area had been reduced 26.752×104hm2, and almost 32 percent for 15 years, which equaled to reducing 2 percent more a year, and the whole status had present the descending trend. From 1989 to 2004, the dynamic degree of grassland had been negative and the grassland had been degraded; The total dynamic degree had been consistent with the dynamic degree of the middle coverage grassland, which had showed that the coverage grassland had larger influence in the whole change of grassland; Seen from the absolute value of dynamic degree, the one of high coverage grassland had been the biggest, which had showed that the degenerate speed was the fastest, and the one of the middle and the low coverage grassland had been relatively smaller, which had showed that the degenerate speed was relatively slow. The western high coverage grassland's area of Jinlin province in 1989 was 23.231×104hm2 and decreased to 9.722×104hm2, which reduced 13.509×104hm2 ; The western middle coverage grassland's area of Jinlin province was 31.570×104hm2 and decreased to 20.734×104hm2 , which reduced 10.836×104hm2. The western low coverage grassland's area of Jinlin province was 29.365×104hm2 and decreased to 26.968×104hm2 , which reduced 2.397×104hm2. Seen from each kind of reduced proportion, the one of the high coverage grassland which reduced 58.15 percent was maximum, and the one of the low coverage grassland which reduced 8.16 percent was minimum, it was obvious that the high-quality's high coverage grassland was damaged seriously, which showed that the degeneration of the high coverage grassland was the most serious in the three species of grasslands.Through the superimposition of the remote sensing interpreted chart and the extraction of the attribute's information in the two years, we got the dynamic change's data of each kind of grassland in the research area from 1989 to 2004. The transfer of the high coverage grassland had been relatively complex, 57 percent of the high coverage grassland had been transformed to the farmland (glebe and paddy field), and secondly, 25 percent of one had been transformed to the middle coverage grassland and the low coverage grassland; There had been a lot of the converted type of the middle coverage grassland from 1989 to 2004, including converting into glebe, low coverage grassland, sand and saline and so on. The converted type of the low coverage grassland had been relatively simple, which had mainly converted into glebe, middle coverage grassland, and saline.The damaged extent's diagnosis of the ecosystem was the foundation and premise of restoring the ecology, and for further study, the author chose the coverage degree of the vegetation, the biomass, the soil salinization and desertification's degree, the value index of the ecosystem service and the precipitation as index, and established the evaluating indicator system of the ecosystem degeneration degree's diagnosis in Jilin's western grassland with the research of the team on the basis of analyzing the former research. Using the hierarchical analytical method to endow with the weight to the index, and doing the synthetical diagnosis to the damaged extent of the western grassland's ecosystem in Jinlin, we got the diagnostic result, which showed that the western grassland's ecosystem in Jinlin was divided into three levels, they were respectively the mildly damaged grassland, the moderately damaged grassland and the severely damaged grassland.According to the diagnosis of the damaged extent of the western grassland's ecosystem in Jilin, we analyzed the destroyed factors, which was respectively natural factor and human factor. Under the condition of the nature change and the human destruction, the ecosystem had been damaged. There had been many phenomena to prove the grassland community damaged, including the converse succession of the grassland vegetation, the change of the soil physical and chemical nature, and including the decline of the community's level biomass and the ecosystem service's function too.On the basis of researching the grassland destroyed mechanism, I established the kinetics model of the Jilin's western grassland production and construction's system and planed to design the reasonable project which was suitable for local production and construction. Based on the Da'an city's specific situation, I utilized system kinetics method and designed to made the model of the Da'an city's agriculture and animal husbandry's sustainable development.Combined the system's kinetics method with the agriculture and animal husbandry theory, I hold on the key link of restricting the agriculture and animal husbandry's sustainable development, and established many items'variable including the per capita income of the agriculture and animal husbandry's workers, the eco-efficiency index, the population, the available land and so on, and use VENSIM software to make Da'an city's ecological restoration model. After making the model, I utilized the actual data from 1997 to 2005 to test the model. The result showed that the relative error of forecasting data and actual data were all smaller than 5 percent, which showed that the model could reflect the Da'an city's agriculture and animal husbandry development well, and forecast the city's future development and frame reasonable development model.According to the Da'an city's actual situation, the author designed three schemes: ecological restoration type, production and construction type and the balance of ecological and economic projects. The production and construction project was referred to forcing on improving the per capita income, and reducing the index of ecological benefits and the decrease of available land area. The ecological restoration project was that even regarded the index of ecological benefits and the restoration of available land area, and improved ecological benefits, and increased the available land area for purposes and ensured the employees'per capita income increasing gradually at the same time. Ecological Restoration project was that ensured rapid economic development simultaneously, gave attention to the increase of the index of ecological benefits and the persistent restoration of available land area, and strove to resolve the contradiction of the enhancement of productivity and the ecological environmental protection , and found the combining site of enhancing productivity and improving the ecological environment. |
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