Emergy Evaluation and Economic Performance of Agriculture Circulation System in Beijing Miyun Water Protective Area

摘要

The aim of this paper is to evaluate the agro-planting subsystem and mushroom cultivation subsystem and both the two??s circulation system of a case study in Beijing Miyun water protective area using the emergy accounting methodology. The main findings of this work were that the agro-planting stage uses the highest amount of resources and has lower emergy yield rate (EYR) and emergy loading rate(ELR), the mushroom stage has higher EYR, is a more effective method to increase economic output using more non-renewable resources and purchased resources, but its environmental loading ratio is very high which means its sustainability is low. Actually, mushroom production is economically profitable and sustainable only when the system is syncretic with the planting system by affording the original materials of which is a circulation system. The circulation system??s emergy yield rate(EYR) and emergy sustainability index(ESI) is comparative high than the two subsystems. Result demonstrate that extending the planting system chain to produce mushroom using planting wastes is one important method that can ensure higher economic profit and lower environment stress, the government should encourage this mode and provide so quantitative subsidies to the farmers and managers who takes this mode.