京郊农业生物循环系统生态经济能值评估——以密云尖岩村为例

国内外学术界和决策者对于循环农业给予了相当关注,但关于循环农业研究,从产业经济角度进行定量分析目前仍处于相对匮乏状态.以京郊典型的尖岩村农业生物循环农业范式为案例,采用能值方法,以翔实的数据描述了从种植、养殖到食用菌生产的各个阶段能量输入与输出,通过能值评估指标体系判断在整个循环产业链条中,各生产环节对环境经济产生的影响,结果显示:(1)农业生物循环系统的能值投资率(2.57)较养殖(116.23)、食用菌子系统(158.73)低；环境负荷率(1.40)也较养殖子系统(7.24)、食用菌子系统(13)低,表明,该循环模式可减少对自然资源和外来经济投入的依赖,能够获得自身的资源补偿.(2)农业生物循环系统的净能值产出率和可持续发展指数较高,说明,该模式有较强的获利性,是较理想的产业系统,在北京郊区推广价值较高.

Emergy evaluation of an agro-circulation system in Beijing suburb: take Jianyan village as a case study

Researchers and decision makers paid close attention to cycled agriculture, but few studied quantitatively with the point of industry economy. The aim of this paper is to evaluate an agricultural circulation system as a case study using the emergy accounting method. This agricultural circulation system consists of three subsystems: agro-planting subsystem, cow-breeding subsystem and mushroom cultivation subsystem. Results showed that cow-breeding subsystem and mushroom cultivation subsystem use large amounts of purchased resources and have lower emergy yield ratio and also have higher investment ratio and environmental loading ratio, it means that these subsystems had depended on the outer inputs and their sustainability is very low. Actually, both of the two subsystems are economically profitable in the case that they are syncretic with each other and with planting subsystem by affording the original materials and disposaling the wastes. The emergy investment ratio and environmental loading ratio of the circulation system is lower than the subsystems. it indicated that the agro-circulation system decreased the dependence on the outer economical inputs and natural resources, and can compensate the used resources. Furthermore, the emergy yield ratio and emergy sustainable indices of the agro-circulation system is relatively higher than the separate subsystems, which demonstrated that this model can ensure higher economic profits. The government should encourage this model and provide so quantitative subsidies to the farmers and managers who takes this model.