生态脆弱区资源型城市农业生态系统的能值分析——以榆林市为例

Emergy Analysis of Agro-ecosystem of Resource-based City in Vulnerable Eco-regions——A Case of Yulin City

【目的】研究生态脆弱区资源型城市农业生态系统的发展现状与影响该系统可持续发展的症结。【方法】采用能值分析方法,对榆林市2000—2008年农业生态系统的投入产出状况及综合发展水平进行分析。【结果】投入产出结果显示:榆林市农业生态系统能值投入以无偿能值为主,2008年工业辅助能占总能值投入的比例仅为全国平均水平的26%,而劳动力能值占可更新有机能的比例高达68%,仍处于主要依赖人力和环境资源的传统农业阶段。综合评价结果显示:榆林市农业生态系统具有较高的发展潜力和较强的可持续发展能力。其中,自然系统发展水平相对优越;经济系统发展水平偏低,但发展潜力较大;社会系统发展水平不断提高,但农村劳动力生产效率较低;2008年,优势度指数为0.71,优势产业(畜牧业)明显;稳定度指数仅0.49,自稳定性有待增强;可持续发展指数为2.76,系统富有活力。【结论】今后应提高可更新资源利用效率、优化系统结构、加大农业科技辅助能值投入,使系统能值的投入产出向高水平发展,使传统的粗放型经营方式向现代科学技术型、高度集约型和高效益型转变。

【Objective】 The development state and major sustainable development obstacle of ago-ecosystem about resource-based city in vulnerable eco-regions were studied.【Method】 The input and output state and comprehensive development level of ago-ecosystem in Yulin city,from 2000 to 2008 were analyzed by using the method of emergy analysis.【Result】The results of emergy input and output showed that the main emergy input of agro-ecosystem of Yulin city was unpaid emergy.The industrial assistant emergy of the total emergy input ratio in 2008 was only 1/4 of the national average,while the labor emergy accounted for up to 68% of renewable organic emergy;the ago-ecosystem of Yulin city was still in the stage of traditional agriculture and depended on manpower and environmental resources.The results of comprehensive evaluation showed that the development potential in Yulin City is high and it has strong sustainable ability of ago-ecosystem.The development state of the natural ago-ecosystem is relatively superior.The development state of the economic ago-ecosystem is low,but the development potential is great.The development state of the social ago-ecosystem was improved,but the production efficiency of rural labor was low.In 2008,the production superiority degree index was 0.71 and the competitive industry（livestock） was obvious;the system stability degree index was only 0.49 and the stability of itself needs to be enhanced;the emergy sustainability index was 2.76 and the ago-ecosystem was a dynamic system.【Conclusion】Some measures should be taken to make the ago-ecosystem input and output emergy to a higher level and make the traditional extensive mode to modern scientific technology,highly intensive and high efficiency,such as improving renewable resources use efficiency,optimizing system structure,increasing the investment of agricultural science and technology assistant emergy.