土壤含水量对探地雷达探测植物根系构型精度的影响  

Effect of soil moisture content on the accuracy of root configuration detection by ground penetrating radar

作　　者：王勃 张建军[1,2] 赖宗锐 赵炯昌[1] 胡亚伟 杨周 李阳 卫朝阳 WANG Bo;ZHANG Jianjun;LAI Zongrui;ZHAO Jiongchang;HU Yawei;YANG Zhou;LI Yang;WEI Zhaoyang(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Jixian National Forest Ecosystem Observation and Research Station,Chinese National Ecosystem Research Network,Jixian 042200,Shanxi,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]山西吉县森林生态系统国家野外科学观测研究站,山西吉县042200

出　　处：《干旱区研究》2024年第3期456-466,共11页Arid Zone Research

基　　金：国家重点研发计划(2022YFE0104700)。

摘　　要：根系是评价植被生态服务功能的关键基础要素,但快速、精确、无损确定根系的测量技术和方法是目前生态系统评估中的瓶颈。探地雷达是一种高效无损的地球物理学技术,可以在无损状态下获取土壤中的根系信息。但是探地雷达检测和识别根系的精度受土壤含水量、根系含水量、根径大小、根系埋藏深度等诸多因素影响,导致其在野外根系探测中适用性受限,为了探究土壤含水量对探地雷达探测根系精度的影响,本研究采用野外预埋根系的控制实验,根据探地雷达波速、振幅和根点反射系数的变化,分析了不同土壤含水量条件下根点识别率及根点距离均方根误差。结果表明:(1)根系探测中,探地雷达波速和振幅是判断土壤含水量变化的重要参数;(2)随着土壤含水量的增大,探地雷达波速减小,雷达振幅趋于平缓;(3)不同土层深度上随着根系直径的增大,探地雷达波速增大,雷达振幅趋于激烈;(4)根点识别率与土壤含水量成负相关(P<0.05),土壤含水量为15%~25%时探地雷达对活根的识别效果最佳。本研究表明探地雷达可以作为植物根系生物量无损和快速测定、评估的方法,但在利用探地雷达测定土壤中根系时,应在土壤含水量相对较低的时间段进行。Root biomass is an important part of the soil ecosystem,however,due to the limitations of measure-ment techniques and methods,it is impossible to rapidly assess it.The ground penetrating radar(GPR)is an effi-cient and nondestructive geophysical tool through which root information can be obtained without damaging the soil environment.However,accuracy during the detection and identification of underground roots by GPR is sig-nificantly affected by many factors such as soil water content,root roughness,length,and extension direction.In particular,soil water content has an obvious effect on root detection.In this study,in situ root embedding detec-tion experiments were carried out to investigate the influence of soil water content on root detection via GPR.Combined with the changes in wave velocity,amplitude,and the root reflection coefficient of the GPR,the root point identification rate and root point distance root point root mean square error were analyzed under different average soil water content.The results showed that(1)the wave velocity and amplitude of the GPR were impor-tant parameters to determine variations in soil water conten during root detection;(2)the GPR’s velocity de-creased and the radar amplitude flattened with the increasing soil water content;(3)as the root diameter increased at different soil depths,the GPR’s wave velocity also increased and the GPR’s amplitude tended to be drastic changes;(4)the root point recognition rate and soil water content were negatively correlated(P<0.05),and the best recognition effect was achieved when the soil water content was 15%-25%.These results are great signifi-cance for quantifying the effect of soil moisture content on the root detection accuracy of the GPR.In addition,it provide a reference for using this tool for root detection and are particularly important for the estimation of plant root biomass.

关 键 词：探地雷达 根系 土壤含水量 无损探测 晋西黄土区 

分 类 号：S152.7[农业科学—土壤学]