采样间隔对城市表土剖面磁化率变化的影响  

Study on the effect of urban topsoil sampling interval on the variation pattern of magnetic susceptibility of soil profile

作　　者：陈明 刘亮[1] CHEN Ming;LIU Liang(College of Forestry and Grassland,College of Soil and Water Conservation,Co-Innovation Center for Sustainable Forestry in Southern China,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学林草学院、水土保持学院,南方现代林业协同创新中心,江苏省水土保持与生态修复重点实验室,江苏南京210037

出　　处：《南京林业大学学报(自然科学版)》2023年第6期61-69,共9页Journal of Nanjing Forestry University:Natural Sciences Edition

基　　金：国家自然科学基金项目(42277352,41701310)。

摘　　要：【目的】探究采样间隔对城市土壤剖面磁化率测量精度的影响,为城市土壤质量研究及评价提供参考。【方法】以南京市及其城郊的典型林地为研究对象,选择4个代表性样地(城郊林场、城内林场、未扰动和扰动道路绿化带),分别采集0~30 cm表层土。以土壤磁化率为主要指标,设置2、5、10、15和30 cm 5种表土采样间隔,分析不同采样间隔下表土质量磁化率和百分比频率磁化率的剖面变化特征。【结果】4个样地剖面土壤低频质量磁化率(χlf)变幅为59.2×10^(-8)~1210.0×10^(-8)m^(3)/kg,峰值出现在5~7 cm土层。各样地土壤剖面低频磁化率基本遵循先增后减和波动变化的情况。经对比,采用精细的采样间隔(如2 cm)可以更好地捕捉土壤磁化率峰值和异常值,从而发现磁性异常累积层。5 cm和10 cm的土壤采样间隔反映了土壤磁化率的大体变化趋势;15 cm的土壤采样间隔则土壤磁化率表现为单调变化;0~30 cm土壤采样间隔的混合土壤样品仅指示各样地表土磁化率的均值。【结论】本研究中,随采样精度的提升,4个样地表土磁化率数据精度逐渐提高,剖面特征逐渐明显。在分析城市表土剖面磁化率的采样过程中,应根据研究目的设置合适的采样间隔,以提高检测数据精度。【Objective】This study explored the influence of sampling interval on the measurement accuracy of urban soil magnetic susceptibility.【Method】Taking typical forest land in Nanjing and its suburbs as the research object,four representative sample plots(suburban forest farms,urban forest farms,undisturbed land and disturbed road green belts)were selected,and 0-30 cm topsoil samples were collected.Taking soil magnetic susceptibility as the main index,five topsoil sampling intervals(2,5,10,15 and 30 cm)were set.The profile variation characteristics of surface soil mass susceptibility and percentage frequency susceptibility at different sampling intervals were analyzed.【Result】Soil low frequency mass susceptibility(χlf)of the four sample plots ranged from 59.2×10^(-8)to 1210.0×10^(-8)m^(3)/kg,with a peak value of 5-7 cm.Low frequency magnetic susceptibility of soil profiles in all plots basically followed the pattern of first increasing and then decreasing and fluctuating.Fine sampling intervals(such as 2 cm)better captured the peak value and abnormal values of soil magnetic susceptibility;the 5 and 10 cm soil sampling intervals reflected the general variation trend of soil magnetic susceptibility;the soil sampling interval of 15 cm showed no detail in the soil magnetic susceptibility changes.Mixed soil samples at 0-30 cm soil sampling intervals only indicated the mean value of magnetic susceptibility of various surface soils.【Conclusion】During the sampling process,appropriate sampling intervals should be set according to the research purpose in order to improve the accuracy of experimental data.

关 键 词：土壤磁化率 表土采样 土壤剖面 分层样品 混合样品 南京市 

分 类 号：S714[农业科学—林学] X53[环境科学与工程—环境工程]