| Popis: |
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. |
