Study On Emergy Analysis Of Gansu Agricultural Eco-Economic Systems

As economic and ecological support systems become more interdependent, new disciplines are needed to "bridge the gap" of understanding between human and nature . As we know that a natural systems and a human economic system are all tied to energy flow. Traditional energy analysis , however, has been criticized in many aspects . One is that various energy types, including materials and services, cannot be compared or totaled only by energy quantity . Emergy created by H.T. Oudm is a new method to evaluate natural capital and ecosystem services . Emergy is defined as the energy of one typer required in transformations to generate a flow or storage . Solar Emergy of a flow or storage is the solar energy required to generate a flow or storage . Its units are solar emjoules (abbreviated sej ).An Emergy analysis of Gansu Agricultural eco-economic systems has performed in order to study its sustainability and emergy use . Indices and ratios of Gansu based on Emergy flow were evaluated and a comparison with indices and ratios of other countries or areas was performed . The Emergy flow of Gansu agricultural ecological-economic systems was divided into 4 parts :(1) Emergy flow of renew able resources;(2) Emergy flow of products of renew able resources;(3) Emergy flow of non-renew able resources;(4) Emergy flow of renew able organic .In 2003 , The total Emergy use (U) of Gansu was 7.64×10²² sej, it includes Emergy flow of renew able resources (R) 1.08×10²²sej (Geopotential energy in dispersed rain);Emergy flow of non-renew able resources (N) 1.43×10²²sej;Emergy flow of unrenew able source production 2.11×10²² sej;Emergy flow of renew able organic 3.03×10²² sej .Some main indices and ratios of Gansu based on Emergy flows were performed : emergy self-sufficiency ratio(ESR) was 99.27% . Emergy perperson (U/Pop) was 5.62×10¹⁵ sej. Emergy density (U/Area) was 3.11×10¹⁵ sej/m². Emergy/dollarratio (U/GDP) was 11.88×10¹²sej/ $ . Environmental loading ratio was 3.73 . Through the research , following results and suggestions were presented :(1) The Emergy self-sufficiency ratio of Gansu was 99.27% . It means that Gansu agricultural eco -economic systems were main relied on the localre sources .The Gansu agricultural eco-economic systems were not open and sustainable systems . Onthe other hand, there is a great potentiality to develop the resources of Gansu. So, attraction of more foreign emergy (capital ,information, technology) is the very important tactic to the sustainable development of Gansu.(2) Emergy densityis much lower, which shows that Gansu is an agricultural area. In 2003 , non-renew able resources are 81.11% of its total Emergy use , which shows that agricultural eco-economic systems development is mostly depended on the devotion of raw materials. So Gansu should speed up to develop knowledge econcentrated industry for future sustainable development.(3) In 2003 , net loss of top soil Emergy is 1.43*1022 sej. It is 18.72% of total Emergy use of Gansu, which shows that soil loss is a very important problem in Gansu province . It is a key for the further development of agriculture, forestry, and animal husbandry in Gansu province . So the projects of returning farm land to forest (grassland), protect natural forest, and desert-control are good for controlling of soil loss.