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| Evaluation of agrosystem eco-efficiency using a coupling model of emergy analysis and life cycle assessment: A case study in the suburbs of Beijing City, China |
| Received:October 02, 2017 |
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| KeyWord:sustainable development;eco-efficiency;emergy analysis;life cycle assessment;farmland ecosystem |
| Author Name | Affiliation | E-mail | | WANG Yi-chao | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | | | ZHAO Gui-shen | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | zhgsh@cau.edu.cn | | PENG Peng | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | | | LIANG Long | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | | | LI Cai-lian | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | |
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| Abstract: |
| Eco-efficiency is an important and widely used index for quantitatively measuring economic system sustainability. In the present study, a coupling model was developed by integrating emergy analysis and life cycle assessment, with the goal of assessing expected and undesirable output efficiencies of production systems for three typical crops(maize, vegetables, and peach) in the suburbs of Beijing City. The emergy input-output ratios of maize, vegetables, and peach were 6.61×104, 1.47×105, and 1.92×105 sej·J-1, respectively, and the expected output efficiency per unit production was highest for maize and lowest for peach. The undesirable output efficiency of maize, vegetable, and peach production was 1.29×106, 1.60×105, and 2.59×105, respectively, and the undesirable output efficiency was highest for maize and lowest for vegetables. The indicators of eco-efficiency for maize, vegetable, and peach production were 2.95×10-4, 7.42×10-6, and 7.05×10-6, respectively, and eco-efficiency was highest for maize and lowest for peach. By taking vegetables production system as an example, sensitivity analysis which was conducted to testify the relationship between all kinds of inputs and eco-efficiency, indicated that electricity consumed in irrigation was the first influential factor, followed by nitrogen fertilizer, manure, and pesticide. When regulating planting structure, the eco-efficiency of production systems should be considered along with other important factors, such as yield and income. Eco-efficiency could be increased by using more manure; however, the heavy metals in organic fertilizer might negatively impact human health. Therefore, strategies like planting water-saving crops, developing water-saving methods, and substituting organic fertilizer for chemical fertilizer could remarkably improve the eco-efficiency of farmland ecosystems in the suburbs of Beijing City. |
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