摘要
Ground-penetrating radar (GPR) has been used predominantly for environments with low electrical conductivity like freshwater aquifers, glaciers, or dry sandy soils. The objective of the present study was to explore its application for mapping in subsurface agricultural soils to a depth of several meters. For a loamy sand and a clayey site on the North China Plain, clay inclusions in the sand were detected; the thickness, inclination, and continuity of the confining clay and silt layers was assessed; and a local water table was mapped. Direct sampling (soil coring and profiling) in the top meter and independent measurement of the water table were utilized to confirm the findings. Also, effective estimates of the dielectric number for the site with the dielectric number of moist clayey soils depending strongly on frequency were obtained. Thus, important properties of soils, like the arrangement and type of layers and in particular their continuity and inclination, could be explored with moderate efforts for rather large areas to help find optimal locations for the time-consuming and expensive measurements which would be necessary to detail a model of the subsurface.
Ground-penetrating radar (GPR) has been used predominantly for environmentswith low electrical conductivity like freshwater aquifers, glaciers, or dry sandy soils. Theobjective of the present study was to explore its application for mapping in subsurface agriculturalsoils to a depth of several meters. For a loamy sand and a clayey site on the North China Plain,clay inclusions in the sand were detected; the thickness, inclination, and continuity of theconfining clay and silt layers was assessed; and a local water table was mapped. Direct sampling(soil coring and profiling) in the top meter and independent measurement of the water table wereutilized to confirm the findings. Also, effective estimates of the dielectric number for the sitewith the dielectric number of moist clayey soils depending strongly on frequency were obtained.Thus, important properties of soils, like the arrangement and type of layers and in particular theircontinuity and inclination, could be explored with moderate efforts for rather large areas to helpfind optimal locations for the time-consuming and expensive measurements which would be necessary todetail a model of the subsurface.
基金
Project supported in part by the Deutsche Forschungsgemeinschaft (DFG), Germany (No. RO 1080/8-1)
jointly by Max-Planck Gesellschaft and the Chinese Academy of Sciences through a travel grant to the first author.
