北京郊区多目标产出循环型农业效益评估——以房山区南韩继大型养猪—沼气生态经济系统为例

随着资源危机与环境压力日益增大，循环农业在现代农业经济中发挥着重要作用。本文以房山区周口店镇南韩继村沼气站和南韩继村养猪场为研究对象，采用能量、能值和经济评价方法分别对北京郊区典型万头猪场、运行十几年的沼气发酵系统及二者相互循环后的生态经济系统效益进行了综合评估，从而对北京郊区循环农业发展的基本形式进行了定量分析，将为京郊循环农业的进一步发展提供决策依据。研究表明，从能量角度而言，二者循环以后，总能量产出效率为1.77，总能量投入经济产出效率为87%，分别比两个单独亚系统（养猪亚系统：1.37、64.1%，沼气亚系统：0.35、0.31）都大大提高；从能值角度而言，二者相互循环以后，净能值产出率为38.04，比猪场净能值产出率（161.5）降低，但使沼气站净能值产出率由负变为正，有力证明了农业系统经过循环以后，循环效益显著增大；从经济评价角度，二者相互循环以后，财务内部收益率为26.8%，大于设定的基准财务收益率10%。在设定的折现率15%时，财务净现值=261.0万元>0，投资回收期为3年，说明，循环生态经济系统在财务上也具有可持续性，经济效益显著。

Comprehensive Evaluation on the Multi-output Cycling Agriculture in Beijing Suburb

crisis and Nanhanji Cycling agriculture plays important role in modem agricultural development for the global energy environmental pollution. In this article we take the big hoggery-biogas eco-economy system in village, Zhoukoudian town, Fangshan district for a case study, and using the method of energy, emergy and modem economy assessment, the eco-economy system is comprehensively Evaluated. The quantitatively analysis and evaluation result will be scientific basis for further development of Beijing cycling agriculture. The result showed that ① in energy point, after cycling, the total energy output efficiency is 1.77 and the total energy input economy efficiency is 87%, greatly increased than the single subsystem. ②In emergy point, after cycling, the net emergy yield ratios is 38.04, less than the sub-hoggery system and make the sub-biogas system from negative to positive. This proved that the cycling benefits of the agricultural system increased greatly.③In economy point, after cycling, the FIRR（Financial Internal Rate of Return）is 26.8%, more than ic（10%）, and the FNPV（Financial Net Present Value） is 261.0 Wan ￥, this is 〉0, simultaneity the Pt （Investment return term）is 3 year, all this showed that the economy benefit of the cycling eeo-economy system is feasible and continuable.