| Developing circular agriculture is an effective way to achieve cleaner production and sustainable utilization of resources.It is also an inevitable choice to solve the dilemma in the development of modern circular agriculture.Based on the summary of the development course and mode of circular agriculture in Hongya county,this paper investigates actual emergy input-output,emergy input-output in each subsystem,related emergy input and the evaluation of comprehensive indexes for emergy in agriculture of Hongya County in recent 37 years（1980-2016）by using a questionnaire method of farmers,emergy analysis and emergy synthetic factor assessment,so as to provide a theoretical foundation for the development of circular agriculture in this county.Through study,the following conclusions are drawn:（1）In last 37 years（1980-2016）,the annual mean value of actual emergy input in circular agriculture of Hongya County was 8.10×1020,showing a decreasing trend.Among them,renewable organic emergy input amount was the largest,accounting for85.34%.The proportion of unrenewable industrial emergy was relatively low,accounting for 10.41%.（2）In terms of emergy input in each subsystem of circular agriculture in recent 37years,emergy input in crop farming,animal husbandry and truck farming accounted for66.41%,14.21%and 19.38%,respectively,in mean emergy input of circular agriculture in this county.Among them,emergy input in crop farming showed a decreasing trend,while emergy input in animal husbandry and truck farming presented an increasing trend.In crop farming,animal husbandry and truck farming in this county,renewable organic emergy>non-renewable industrial auxiliary emergy>renewable environmental emergy>non-renewable environmental emergy.In crop farming,renewable environmental emergy,non-renewable environmental emergy and renewable organic emergy showed a decreasing trend,while non-renewable industrial auxiliary emergy presented an increasing trend.In horticultural enterprise and animal husbandry,emergy input in these 4 indexes showed an increasing trend.（3）In last 37 years,related emergy input in circular agriculture of Hongya County increased from 1.40×1020（sej）to 3.74×1020（sej）.In the total input of circular agriculture,related emergy input of crop farming,animal husbandry and truck farming increased from 12%to 37%,and actual total emergy decreased from 88%to 63%,which showed that multiple recycling of materials,energy and resources was improved during the development of circular agriculture in Hongya County.（4）In last 37 years,the mean emergy output in circular agriculture of Hongya County is 2.40×1021.The ratio of emergy output in crop farming,animal husbandry and truck farming has adjusted from 59.14%:39.29%:1.58%at the early stage to 23.42%:55.56%:21.15%at the later stage,suggesting that the emergy structure of agriculture has constantly optimized and upgraded,especially the proportion of emergy output in animal husbandry increased significantly.（5）In last 37 years（1980-2016）,emergy self-sufficiency rate,net emergy output rate,per capita emergy utilization and per capita emergy output of circular agriculture in Hongya County showed an upward trend,suggesting that Hongya County has a relatively high standard of living and a relatively good development trend in rural areas,constantly optimized emergy input-output structure of circular agriculture,and better economic development.However,emergy investment ratio and emergy density showed a downward trend,demonstrating that there is still much room for the growth of economic feedback emergy input in Hongya County,and the degree of intensivism is low.The average environmental carrying rate was higher than 2,and agricultural economic activities had a great impact on system environment.In recent 37 years,sustainable development index in the early stage（before 2008）was less than 1,suggesting high consumption-driven agriculture.Sustainable development index after2008 has been over 1,indicating that circular agriculture in Hongya County is gradually energetic. |
