| Agriculture is the foundation of the national economy. Carrying out quantitative evaluation of the sustainable development of agriculture, tracing and analyzing the development trends of Agro—eco—economics system, putting forward science rational suggestion and planning possesses are therefore tremendously significant for supporting the unity of the state and the social development. The object of study is Hunan agricultural eco—economy system. Utilizing the emergy analysis, the paper conducted a dynamic study to the operation conditions of the Hunan agricultural eco—economy system between 1994-2008 and comparatively analyzed the emergy indicator which can reflect the structure and function. It also analyzed the sustainable development system. By using the factor analysis method, this paper analyzes the influential factors of the emergy output of agriculture eco-economic system in Hunan with software SPSS. The results of the studies are listed as follows:(1) The total emergy input of the agriculture in Hunan increases smoothly. In 1994, the total emergy input of the agriculture in Hunan was 6.28E+22sej and in 2008,to 6.92E+22sej. The main reason of the increase was that the input of the industrial auxiliary emergy value rose considerably but the input of the organic emergy value subtracted obviously.(2) The total emergy input of agriculture in Hunan was large and increased rapidly. In 1994, the total emergy input of the agriculture in Hunan was 1.75E+23sej and in 2008, to 3.07E+23sej. That is to say it increased by 75.43%, which indicated the output of the major farm produce from Hunan increased significantly.(3) The ratio of output/input of the emergy value increases obviously. In 1994, the total emergy input of the agriculture in Hunan was 2.79 and in 2008, to 4.43. The net emergy yield tatio increased from 3.35 to 5.14. The results indicated that the agricultural production efficiency in Hunan was comparatively high.(4) The environment loading ratio increased from 6.46 in 1994 to 8.32 in 2008. In spite of somewhat fluctuating during 2003 and 2008, it still showed an up trend, which showed the more economical emergy was invested, the more serious the environment pollution was led to.(5) The emergy output for person increased from 8.26E+15sej in 1994 to 1.78E+16sej in 2008. The clear profit for person increased from 5.30E+15sej in 1994 to 1.38E+16sej in 2008, which indicated that the income of farmers was steadily increasing.(6) The emergy self-sufficiency rate decreased from 20% in 1994 to 16% in 2008, which indicated that the agricultural production in Hunan depended weakly on natural resources.(7) The emergy input radio increased from 4.99 in 1994 to 6.25 in 2008. The results showed that agricultural products were competitive with the large investment of the economical emergy and the comparative low input of the natural resources emergy.(8) The property index of the sustainable development reduce from 7.86 to 5.96. In spite of some fluctuation, it could be controlled within some desirable range, which indicated the agriculture in Hunan qualified the condition of the sustainable development.In view of the input and output structures, the total emergy input of agriculture eco-economic system in Hunan was not very high in comparison with the input in other provinces. However, the emergy output was comparative high, especially the agricultural products, such as pig, rice and rape, was among the front ranks in China. Accounting for large proportion, it can meet the requirement of the major agricultural province. Since the agricultural product process and manufacture were still underdeveloped, it was the main form that the primary products reached the market. Therefore, the actual income of farmers was pretty low.In view of the diversity emergy index, emergy self-sufficiency tatio was very low; the average usage of emergy is pretty low; the input tatio of economical emergy, the output tatio of the net emergy. environmental loading ratio, the emergy investment ratio were very high; the average usage of emergy was relatively high and emergy density was high; the emergy of the sustainable development was comparative reasonable. To maintain the sustainable development of the agriculture, the usage of renewable energy must be improved and the environmental pressure which created by industrial auxiliary emergy (chemical fertilizer, pesticide and plastic membrane, etc) must be reduced.The result shows that the Agro—eco—economics system in Hunan should be developed positively and the input emergy be optimized. Besides, the supplementary energy should be used rationally to develop farm produce processing industry and improve the tatio of net emergy. |
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