民勤绿洲农田生态系统能值空间分异特征

利用能值分析方法对2011年民勤绿洲18个乡镇农田生态系统的环境资源条件、投入产出结构和可持续性进行了系统分析，构建了反映民勤绿洲农田生态系统综合水平的能值指标体系，运用主成分分析方法对其进行了综合评价和排序。结果表明：民勤绿洲农田生态系统可持续性强的是夹河乡，其他乡镇农田生态系统为消费型生态经济系统，可持续性弱；民勤绿洲农田生态系统能值综合水平存在着明显的地域差异，呈现东北片高于西南片、绿洲边缘带高于中心带的地理分布特征；民勤绿洲农田生态系统总体上不具有可持续性，不协调发展型区域和极不协调发展型区域农田面积占民勤绿洲农田总面积的73.68%，强、中、弱协调发展型区域只占26.32%。因此，目前民勤绿洲农田生态系统面临的不可持续性应当引起相关部门的高度重视。

Characteristics of Emergy Spatial Heterogeneity of Farmland Ecosystem in the Minqin Oasis

Based on a systematical analysis on the resources environment, structure of input and yield, and sustainability of the farmland ecosystem in 18 towns in the Minqin Oasis in 2011 with the emergy analysis method, we established a comprehensive emergy index system for the farmland ecosystem, evaluated and sorted the farmland ecosystem comprehensively by using principal component analysis method. The results showed that: Jiahe town and Hongshaliang town had higher sustainability of farmland ecosystem, the other towns belonged to consumer ecological economic system and had low sustainability; There was a clear regional difference of farmland ecosystem in the Minqin Oasis which presented a geographical distribution of "northeast high, southwest low, and oasis edge band high, center zone low"; The farmland ecosystem in the Minqin Oasis on the whole was not sustainable, farmland area with no and highly disharmonious development regions accounted for 73.68% of the total farmland area, the farmland area with strong, relatively strong and weakly harmonious development regions accounted for 26.32%. Therefore, the present unsustainable status that the farmland ecosystem in the Minqin Oasis encountered should be paid enough attention by the local government.