Evaluation Of Sustainable Development Of Farmland Ecosystem In Guanghe County Based On Emergy Analysis

Guanghe County is located in the southwest of Gansu Province,the southeast of Linxia Hui Autonomous Prefecture,the east of Lintao County of Dingxi City,the west of Hezheng County,the south of Kangle County,and the north of Dongxiang Autonomous County.Guanghe county is a hilly area with serious soil and water loss and few available water,which leads to the fragile ecological environment.Secondly,because of its strong characteristics of ethnic regions,large population and land,sharp contradiction between people and land,and heavy load of farmland system.In addition,Guanghe County belongs to the national poverty county,the farmland system investment is little,the ecosystem stability is poor,the sustainability is weak,resulting in the rapid deterioration of the ecological environment in Guanghe County.Therefore,it is very important to study the energy input and output of farmland ecosystem in Guanghe county and to evaluate the sustainability scientifically.Energy analysis theory is applied in this article,using principal component analysis and regression analysis methods,in order to vitalizing national economy.It is farmland ecosystem based on input-output data of 2005-2005,farmland ecosystem of vitalizing national economy.it has carried on the analysis and evaluation.The main findings are as follows:(1)The total emergy input of farmland ecosystem in Guanghe County decreased slightly at the end of the stable period.The environmental contribution rate increased from 0.34 to 0.37 and then decreased to 0.34.The proportion of renewable organic energy in total energy input decreased from 39.35% to 35.32%,and the proportion of non renewable auxiliary energy increased from 25.24% to 29.25%.The maximum ratio of chemical fertilizer to the non renewable industrial auxiliary energy is 58.07%.Non renewable auxiliary energy mechanical energy input growth from 25.65E+18 sej to 51.86E+18 sej,increased by 102.18%,that of the county farmland ecosystem modernization gradually strengthen,the degree of mechanization continues to improve,but the ability of sustainable development environment has the tendency to reduce.There are significant differences in the degree of economic development of farmland ecosystem in the county.Compared with the villages and towns around the county,the intensity and level of economic development of farmland ecosystem are relatively high.(2)The total emergy output of farmland ecosystem in Guanghe County increased first and then decreased.Corn,potato,beans,wheat and oil have been the main energy output crops in the farmland ecosystem of the whole county.The emergy output of corn,oil and potato have all increased,in which potato increased 4.44 times,oil increased 1.20 times.Corn increased 2.00 times.Although the proportion of emergy output of beans and wheat was small,it showed a downward trend on the whole.It shows that the planting of high-energy crops is increased and the planting of high-input and low-output crops is reduced in the whole county.On the whole,the equilibrium degree of crop structure of farmland ecosystem in the whole county showed a downward trend,from 1.06 in 2005 to 0.75 in 2015 years.The relationship between emergy output density and planting structure equilibrium degree is negative correlation.(3)The output rate of net energy value of farmland ecosystem in guanghe county showed an upward trend on the whole.the output rate of net energy value of farmland system in guanghe county increased by 70.16 % in eleven years,which indicated that the efficiency of farmland system in guanghe county was greatly improved.The major input factors affecting the total emergy output in the whole county were organic fertilizer,animal power and agricultural machinery.(4)During the study period,the county sustainable development index except 2011,has been less than 1.The results show that the net energy output of farmland ecosystem is low and the environmental load is high,which belongs to typical consumption-type eco-economic system and the sustainable development ability of the system is weak.The spatial difference of sustainable development index of farmland system is great.Except for Miajiaxiang town,Shuiquan township and Zhuangheji town,the sustainable development index level of other towns in Guanghe county is generally lower.The spatial distribution characteristics of the comprehensive level of sustainable development in the whole county are Zhuangheji Town,Mijia Xiang Town,Shuiquan Township and Guanfang Township in Southwest region,which are obviously higher than those in Qijia Town,Qijiaji Town,Chengguan Town and Sanjia Town in Northeast China.73.68% Of the farmland in the whole county is in a state of uncoordinated development and extremely uncoordinated development;only 26.32% of the farmland ecosystem is stable and the comprehensive development level is high.The ability of sustainable development of farmland ecosystem in the whole county is weak and the development is not coordinated.