| 县域尺度土壤铜的有效性及相关影响因素评估 |
| 摘要点击 1836 全文点击 641 投稿时间：2017-05-18 修订日期：2017-07-04 |
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| 中文关键词 土壤 有效铜 调控 空间非平稳性 地理加权回归 |
| 英文关键词 soil available copper regulation spatial nonstationary geographic weighted regression |
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| 中文摘要 |
| 了解土壤重金属相关属性（如全量、有效态含量等）的空间分布状况及相关环境因子对其有效性的空间非平稳影响，对土壤重金属风险区域的划定和空间调控措施的制定具有重要作用.本研究基于张家港市357个土壤样本数据，首先探讨了土壤类型和土地利用类型对土壤有效铜的影响.然后采用普通克里格预测了该区域土壤全铜和有效铜的含量，计算得到其有效性比率（即有效铜/全铜）的空间分布状况，并结合有效铜及其有效性比率划定了土壤有效铜的风险调控区域.最后，采用一种空间局部回归技术，地理加权回归（GWR）探索了土壤有效铜与3个主要土壤因子（即土壤全铜、pH和SOM）之间的空间局部回归关系.结果表明，土壤类型和土地利用类型均对土壤有效铜含量存在一定程度的影响.土壤铜的有效性比率具有较强的空间异质性，其变化范围在13.56%~29.15%.模型对比结果显示，GWR模型较传统的普通最小二乘回归（OLSR）模型具有更高的拟合精度（即较大的决定系数R2，较小的AICc信息准则和残差平方和）.GWR分析结果显示，各土壤因子对土壤有效铜的影响在空间上是非稳态的.GWR模型能有效地揭示相关土壤属性对土壤有效铜的空间非平稳影响，其结果可解释局部区域土壤有效铜累积的原因.基于上述分析结果，可以为该研究区域内土壤有效铜的调控提供具体的空间决策支持. |
| 英文摘要 |
| Understanding the spatial distribution of total copper, available copper, and the spatial non-stationary relationships between available copper and relevant environmental factors is important for the delineation of soil risk areas and the development of related control measures. This study was conducted in Zhangjiagang County of Jiangsu Province, China. The risk status for soil copper was assessed based on 357 soil samples in the study area. The effects of soil type and land-use type on the concentration of available soil copper were discussed first. Then, ordinary kriging was adopted to map the spatial distribution patterns of the total soil copper and available soil copper, and the spatial distribution map of the copper availability ratio (i.e., available copper/total copper) was also developed for the study area. The risk areas for soil copper were delineated based on the spatial distribution patterns of available soil copper and the copper availability ratio. Finally, a new spatial local regression technique, geographic weighted regression (GWR), was used to explore the local spatial regression relationships between available copper and its three main impact factors (i.e., total soil copper, soil pH, and SOM). Results showed that both soil type and land-use type had some effect on the concentration of available soil copper. The copper availability ratio had a strong spatial heterogeneity, with the higher values mainly in the northeast, southeast, and northwest of the study area and the lower values mainly in the middle and southwest of the study area. The range of the copper availability ratio is 13.56% to 29.15%. The results of the comparison of the traditional ordinary least squares regression (OLSR) and GWR showed that the GWR model had higher fitting accuracy than the OLSR model[i.e., a larger decision coefficient R2, and smaller corrected Akaike information criteria (AICc) and the sum of squares of residuals] in modeling the relationships between available copper and its three main impact factors. The GWR analysis showed that the effect of soil factors on the concentration of soil available copper was non-stationary. The GWR could effectively reveal the spatial non-stationary influence of the related soil factors on the concentration of available soil copper, and the results could explain the reasons for the accumulation of available soil copper in local areas. Potential risk areas for available soil copper were delineated based on the copper availability ratio and the concentration of available soil copper in the study area. The results should be crucial data for developing specific control measures for soil copper at a regional scale. |
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