JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (6): 61-69.doi: 10.12302/j.issn.1000-2006.202203060

Special Issue: 山水林田湖草一体化保护和生态修复——土壤侵蚀修复研究

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

CHEN Ming(), LIU Liang()   

  1. 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
  • Received:2022-03-28 Revised:2022-07-09 Online:2023-11-30 Published:2023-11-23

Abstract:

【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 1 210.0 × 10-8 m3/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.

Key words: magnetic susceptibility, topsoil sampling, soil profile, profile stratified samples, profile mixed samples, Nanjing City

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