| As a compounding ecological system with "social, economy and environment", county needs metabolism to maintain normal operation. In the natural conditions, substances recycles among organisms, the mechanism of whose synthesis, utilization and degradation is complete, but the substances cycling and energy flow patterns of county ecosystem are changed by humans.With the development of social and economy, human activities are increasing intensively, so that county substances metabolism faces great pressure.Based on the nation-wide material flow analysis (MFA), The paper regards Yanling Country as the research object, analyses whose material flow from 2002 to 2009, discusses metabolism of substances metabolism. The results are as followed:(1) The paper establishes the frame of county MFA, and propose a series of strict estimated methods for some data difficult to obtained directly in the calculation of Yanling county MFA.The empirical study proves that the framework established is feasible, which provides the unified basis with MFA of urban-wide and nation-wide.(2) The number of material output and input in Yanling is larger, which is 8798.85 Mt and 6242.57 Mt respectively in 2009. It shows that the economic development accompany abusing great natural resources in Yanling, which lead much pressure to the local ecological environment.98% of the pollution emissions are solid waste, and most of them are agricultural pollutant and livestock feces that have great potentials in comprehensive utilization.(3) Biomass resources are the main physical structure of output and input in Yanling. The quantities of local mining and foreign derived are 8040.68 Mt and 6242.57 Mt in 2009, representing about 95% and 91% of the total respectively. The first industry is the main industry in Yanling, and rich forest is the important source for economic development.(4) The Yanling MFA from 2002 to 2009 shows that the economic development mainly depends on local resources exploitation and utilization. The ratio of the imported materials changes from 8.4% to 6.84%, so the external dependence is not strong. The pollution emissions intensity is 4.89 t/yuan in 2002,2.38 t/yuan in 2009. The fact explains that the efficiency of material utilization is improving in the period, but the material productive forces is only 25.91 yuan/t in 2009, which shows that efficiency of resource utilization is still lower. (5)The main driver metabolic factors in Yanling are five aspects:resources factor, environmental factor, geographical factor, population factor, technology factor. It puts forward some appropriate countermeasures and measures for the reasons above, which provides further support for the healthy development of the Yanling County metabolic. |
