Based on analysis of the input and output of various ecological flows in a regional agricultural production system, the positive and negative effects of agricultural water utilization were evaluated through emergy analysis from a perspective of ecological economics. Then, with the emergy as a normalized basis, the method of calculating the positive and negative effects of agriculture water utilization was improved. Using Zhengzhou City as an example, the positive and negative effects of water utilization in the agricultural production system of the city in 2011 were calculated. The results show that the positive effect was 1. 62 × 1021 J, and the negative effect was 6. 82 × 1020 J, which was about 42. 10% of the positive effect, indicating that the cityˊs agriculture water utilization was in a significantly negative situation. Improving the utilization efficiency of water resources and the accompanying renewable resources while minimizing the unreasonable investment and utilization of nonrenewable resources, and avoiding the harm caused by environmental pollution and overexploitation of groundwater are the keys to solving the problem of negative effects of agricultural water utilization.%从生态经济学的角度,运用能值分析方法,在分析区域农业生产系统各种生态流投入产出的基础上,探讨了农业生产用水的正负效益,进而以“能值”作为统一的度量尺度,完善了农业生产用水正负效益的计算方法。以郑州市为例,计算了该市2011年农业生产系统用水的正负效益,其中正效益为1.62×1021J,负效益为6.82×1020J,负效益约为正效益的42.10%,表明郑州市农业生产用水存在负面问题较为严重。认为提高水资源及伴随的可更新资源的利用效率,尽量减少不可更新资源的不合理投入和利用,避免因环境污染和地下水超采引发的危害,是减小农业生产用水负效益的关键。
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