Study On Oasis Farming System Emergy Analysis And Sustainable Development In Yanqi Basin

Agriculture is the foundation of national economic development,and farming is an important part of agriculture.Farming sustainable development is an important part of the social-economic sustainable development and a key historical task in northwest arid oasis areas.On the basis of the emergy analysis theory and input-output theory,a case as Yanqi basin,a farming model eco-economic system is established,evaluating the ecological flow inputs-outputs,the net emergy yield ratio,the environmental loading ratio,the energy density, the energy investment ratio and energy-based sustainability indices of farming eco-economic system from the efficiency of resource use,static and dynamic.At the same time,a time-series model from 1997-2006 of farming system emergy analysis is established.Through the analysis from different index of emergy,the research results showed that:(1) The renewable environmental resources to the value of the total inputs of 8.04 percent, the energy density is 1.21E+12 sej,the ratio of environmental loading is 1.32,the rate of energy output is 1.78,the index of energy-based sustainability is 1.62 of Yanqi basin in 2006, which are lower than developed countries and other provinces and cities in China,and it reflects the low level of regional development in the Yanqi basin,and socio-economic development will have a better development potential in the future.(2) The model of farming Yanqi Basin eco-economic system from 1997 to 2006 showed that the total inputs(from 6.28E +20 sej to 9.61E +20 sej) and total outputs emergy(from 1.07E +21 sej to 1.60E +21 sej ) are increasing,but the rate of output-input(from 1.70 to 1.66) are decreasing.The input of industry supplemental energy to the total inputs is 51.34%,and the inputs of system environment has rise from 5.69E +19 sej from to 7.72E +19 sej.Different index show that the Yanqi Basin farming system gradually change from traditional to modern agriculture,the level of farming is increase,the farming system is far from high-input high-yield status,which have still large potential to development.(3) The index of per capita emergy,the energy density,the energy investment ratio of the framing eco-economic system are increasing from 1997 to 2006,but the index of sustainable development decreased from 1.85 to 1.62,and other important index is declining,the rate of environment load slowly increase from 1.09 to 1.32.which not only reflects the farming eco-economic system lack of foreign capital,resources,technology and innovation,at the same time which also shows that farming eco-economic system increasing pressure on the environment,the capacity of sustainable development reduced,which should be pay attention to the development of the farming sustainability,in order to increase the system cost-effective at the same time pay attention to environmental protection,improve eco-efficiency.(4) The ratio of output to input fluctuated between 1.32～1.83,the net energy output rate fluctuated between 1.43～2.06 in the Yanqi Basin farming system,the results showed that the resource useing efficiency becomes lower and lower in the farming system of Yanqi basin. Factor analysis showed that the fertilizers using increased by nearly 1.4 times,machinery increased by almost 1.7 times the energy(electricity) increased by almost 3 times during the last decade,so the emergy input of fertilizers,machinery,electrical are mostly effected the output of farming system.