李淑敏, 李 红, 孙丹峰, 霍霄妮, 周连第. 北京耕作土壤4种重金属空间分布的网络特征分析[J]. 农业工程学报, 2012, 28(23): 208-215.
    引用本文: 李淑敏, 李 红, 孙丹峰, 霍霄妮, 周连第. 北京耕作土壤4种重金属空间分布的网络特征分析[J]. 农业工程学报, 2012, 28(23): 208-215.
    Li Shumin, Li Hong, Sun Danfeng, Huo Xiaoni, Zhou Liandi. Network analysis of agricultural soil heavy metals' spatial distribution in Beijing[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2012, 28(23): 208-215.
    Citation: Li Shumin, Li Hong, Sun Danfeng, Huo Xiaoni, Zhou Liandi. Network analysis of agricultural soil heavy metals' spatial distribution in Beijing[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2012, 28(23): 208-215.

    北京耕作土壤4种重金属空间分布的网络特征分析

    Network analysis of agricultural soil heavy metals' spatial distribution in Beijing

    • 摘要: 以北京市耕作土壤Cr、Ni、Zn、Hg 4种重金属为研究对象,借助ArcGIS、GeoDa、Matlab等软件,将1 018个土壤样点看作网络节点、重金属含量的空间自相关关系作为连线依据,构建Cr、Ni、Zn、Hg网络图,从网络科学角度分析土壤重金属空间格局,并以重金属Hg为例提取高度值节点所在网络簇,计算度、介数、平均最短路径等网络特征。得出以下结论:1)北京土壤重金属Cr、Ni、Zn、Hg网络中高度值节点仅占30%左右,这些节点影响周围较多区域土壤重金属含量并已形成稳定网络结构,重金属污染防治困难加大;2)Hg网络簇具有网络的小世界性特征,而不具有无标度性,承担网络主要流量的高介数节点分布集中,并沿潮白河流向分布,表明河流在网络形成中起到重要作用;3)Hg网络簇的形成一定程度受到土地利用的影响,人类活动带来的大量耕地及工矿用地的分布,是造成北京主城区北、东、南三面土壤Hg含量累积的主要原因。该研究可以为进一步分析土壤重金属污染空间格局特征和扩散演化机制提供参考,实现对土壤重金属污染预防与控制。

       

      Abstract: With ArcGIS, GeoDa, and Matlab, this paper studies the spatial pattern of Beijing agricultural soil heavy metals using complex network theory. Taking 1 018 soil samples as network nodes, and the spatial autocorrelation of soil heavy metals as edges connection reference, we create networks of Cr、Ni、Zn、Hg. And taking network cluster of Hg for example, we calculate network characteristics, such as degree, betweenness, average shortest path, etc. The conclusions of the research are as follows: 1) according to networks of Cr、Ni、Zn、Hg, nodes of high degree value only accounting for about 30%. These nodes affect more regional soil heavy metals around, and have formed stable network structures, which is difficult to prevent and control soil pollution. 2) Hg network cluster is a network of small-world characteristics, but not a scale-free. Nodes with high betweenness, undertaking the main network traffic, are concentrated, and distributed along with the Chaobai river. It's indicating that river play an important role in network formation. 3) Land uses, to a certain, impact the distribution of Hg network cluster. Human activities brought a lot of agricultural and mining sites, which result in Hg accumulation at north, east, and south of the core urban area of Beijing. The research can provide a reference for further analysis of the spatial pattern of soil heavy metal pollution and diffusion evolutionary mechanisms.

       

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