Arid Zone Research ›› 2024, Vol. 41 ›› Issue (3): 456-466.doi: 10.13866/j.azr.2024.03.10

• Land and Water Resources • Previous Articles     Next Articles

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

WANG Bo1(), ZHANG Jianjun1,2(), LAI Zongrui1, ZHAO Jiongchang1, HU Yawei1, YANG Zhou1, LI Yang1, WEI Zhaoyang1   

  1. 1. School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2. Jixian National Forest Ecosystem Observation and Research Station, Chinese National Ecosystem Research Network, Jixian 042200, Shanxi, China
  • Received:2023-09-11 Revised:2023-11-30 Online:2024-03-15 Published:2024-04-01

Abstract:

Root biomass is an important part of the soil ecosystem, however, due to the limitations of measurement techniques and methods, it is impossible to rapidly assess it. The ground penetrating radar (GPR) is an efficient 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 significantly 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 detection 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 important parameters to determine variations in soil water conten during root detection; (2) the GPR’s velocity decreased 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 significance 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.

Key words: ground penetrating radar, root system, soil moisture content, non-destructive testing, loess area of western Shanxi Province