| As one of the major grain producing areas of China, Jilin takes an important place in China’s food security guarantee system. However, under the influence of human factors, the land degradation problems such as the loss of soil and water, the soil erosion become obviously, and both cultivated land production and land ecological service value decrease. Accordingly, it has been an important subject for Jilin Province to balance urban and rural development so as to promote the new urbanization, that how to coordinate land natural quality and the demands of economic social development. Soil is an exchange hub of energy and material in land ecosystem which is a foreland subject of the research between land use planning and management. Therefore, it could provide technical support for the regional land use planning and management to exploring the recovery and reconstruction of land natural production capacity in the process of economic social development of Jilin Province based on land ecosystem theory and technical method.This paper systematically analyzes forecasts and evaluates land-use structure optimization of Jilin province based on GIS software platform. Methods employed are emergy theory, input-output analysis, fuzzy comprehensive evaluation, and grey linear programming. The main research results are as follows:1. The indicator system of land ecological regionalization in Jilin Province is built based on ArcGIS software. PCA (Principal Component Analysis) is used to select main factors which affect land ecosystem of Jilin Province, and calculating the factor loading to ascertain its influencing weight. Then, the basic unit of ecological zones is formed by applying analysis tools to complete the spatial overlay of factor. Finally, the author divides Jilin province into3ecological zones,8ecological sub regions and28ecological units. The results show that the evolution environment of land ecosystem is controlled by climate, hydrology and landform on a macro scale, while vegetation and soil restrict its realization of value on micro scale, and economic and social activities have changed the circulating direction and rate of material and energy of land ecosystem, thus it is able to reconstruct land ecosystem value.2. On the basis of land ecological regionalization, this paper builds classification standard of soil fertility by the method of documentation and comprehensive analysis. The soil quality of Jilin province is evaluated using fuzzy comprehensive evaluation, thus divided into four ranks. Among them, the soil area of first grade quality accounts for8.4%, and the second, third and fourth grade soil is33.2%,34.2%and24.3%. From the special distribute, low quality soil mostly surrounds the west area of Jilin Province, while high quality soil spreads around Changchun, between the northern of Nongan, the eastern of Jilin and the southern of Siping. The soil quality provided natural material base for land use structure and spatial distribution.3. Spatial overlay analyzing land use status and soil quality in Jilin Province, the results showed that: cultivated land, garden plot, woodland and grassland in the high-grade (Grade4) soil area of cultivated land area, the total area of the garden, the total area of woodland and grassland of the total area distributed in20.52%,25.97%,23.57%and10.82%, and agricultural land soil quality degradation, particularly grassland, is relatively common. Compared the proportion of cultivated land, garden plot, woodland and grassland in the area of high-grade soil and province total area’ high-grade soil (35.67%,0.44%,51.64%and1.85%), with that of cultivated land, garden plot, woodland and grassland area and province total land area’(36.78%,0.36%,46.37%and3.61%), it shows that the spatial distribution of agricultural land in Jilin province is reasonable, but requires a certain degree of adjustment.4. Compared soil quality rating with unit level of grain in Jilin Province, it leads to the results that:with the impact of natural and human factors, grain production is decided jointly by the natural soil fertility, planting structure and input level factors. Mountain area of eastern Jilin province has lower grade of soil quality level, and by the constraint of economic input level, soil quality and unit level of grain show strong spatial coupling; although the western plain has a bottleneck of water resource, by the constraint of soil improvement and fertilizer and other agricultural inputs, unit level of grain is generally higher than the grade of soil quality.5. After analyzing the productivity of soil-plant macronutrients abundance of agricultural land, it gets the results that: the soil improvement project and fertilizer inputs of western Jilin province can significantly enhance the contribution of agricultural land productivity; sustained investment at this stage can get higher outputs; the samples of diminishing returns to scale are mainly distributed in the middle of Jilin Province, so at present continued application of nitrogen, phosphorus and potash fertilizer on agricultural land has no economic significance to improve agricultural productivity.6. The purpose of this paper is to deeply analysis circulation characteristics of substances and energy in the soil-crop-economic society system, and to explore the stable condition of land eco-economic system. The evaluation indexes such as environment load rate, emergy self-sufficiency ratio and net emergy output rate are calculated by the data collection and analysis, using time series with county unit based on emergy theory. The calculated results indicate that:(1)The land use of Jilin province belongs to an production mode of paying equal attention to natural and social investment, and the total increase of agricultural production system depends on the input of industry supplemental energy and the affinity of natural environment;(2) The most outstanding problem in the land ecosystem is the continuous increase of environment load rate, the excessive development of land and the overweight ecological load which makes the soil fertility decline continually;(3) From the view of the space distribution, the total emergy output of Changchun district is significantly higher than the other regions, and the central and western region is slightly better than the eastern regions. Besides, the emergy output and soil quality show a space coupling;(4) the environment load rate of Changchun district is higher than the eastern counties. Changchun has good endowment in resources and environment, and possesses a high standard in science and technology development, its economy society is rapidly developing, the total population is continuously growing, the environment load is synchronously increasing and have already emerged some signs of overload. 7. This paper applied input-output analysis, based on the input-output form in2002and2007, and studied on agriculture with the industry spread effect, revenue promotion capacity and employment opportunities provided to the national economy of Jilin Province. The results show that:(1) agricultural output promoting ability and income multiplier effect should be slightly better than other industries in Jilin Province, which proves that the foundation industry status of agriculture has not changed;(2) from the calculation results of labor force multiplier, the tertiary industry has surpassed the traditional labor-intensive agriculture industry in employability, reflecting that the new urbanization in Jilin Province has entered into the stage of accelerated development. Input-output analysis has proved the basic characteristics of the land use management, demonstrating the difficulties in urbanization process of rural land utilization in China.8. This paper selected the ecological service value coefficient and the ecological economic benefit coefficient as the parameters to the optimization model of land use structure, with analyzed the prediction of the relevant constraints, finally formed two optimization schemes of land use structure, which were the linear programming and the gray system programming. Based on MATLAB platform, then calculated the parameters, and finally got the optimization land use structure of Jilin Province:the optimal scale of cultivated land should be kept between553.1and551.0million hectares; the garden plot should be in10to130000hectares; the forest land should be kept from957.9to1012.8million hectares; the grassland should be kept between106and111million hectares; and the land for construction should be kept from107.2to120.2million hectares.9. Based on the emergy theory, studied on land use structure optimization scheme with input-output analysis showed that:(1) linear programming is the highest scheme in both vital and unit area emergy output, respectively as2.0094×1023sej and1.0514×1011sej/m2;(2) the optimization scheme which total investment is greatest is the grey system programming, while the opposite goes to the linear programming;(3)the emergy density of Jilin Province in2020will reach the level of the developed countries’in the world, which shows that Jilin Province has a reasonable economic development scheme, and the linear programming can provide the highest emergy density;(4) per capita emergy of Jilin Province will reach more than1.5×1016sej/person in2020, which is close to the level of the developed countries’, and the scheme goes to the grey system programming;(5) the linear programming model can give us the lowest environment load in2020in Jilin Province;(6) based on the land natural production capacity recovering and reconstructing, and to co-ordinate the quality of land and the needs of economic and social development, the optimization scheme of land use structure in Jilin Province is the linear programming. |
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