Arid Zone Research ›› 2025, Vol. 42 ›› Issue (5): 840-851.doi: 10.13866/j.azr.2025.05.07

• Plant Ecology • Previous Articles     Next Articles

Method for estimating the diameter of Pinus tabulaeformis roots based on ground penetrating radar

WANG Bo1(), ZHANG Jianjun1,2(), ZHANG Haiqiang3, LAI Zongrui1, ZHAO Jiongchang1, YANG Zhou1, LU Shanhong1   

  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
    3. Tianshui Management and Supervision of Soil and Water Conservation of Yellow River, Tianshui 741000, Gansu, China
  • Received:2025-01-01 Revised:2025-03-17 Online:2025-05-15 Published:2025-10-22
  • Contact: ZHANG Jianjun E-mail:wangbo96824@163.com;zhangjianjun@bjfu.edu.cn

Abstract:

The coarse roots play a significant role in supporting the plants and holding the soil firmly. However, in the evaluation of ecosystems, it is still impossible to determine the biomass of the coarse roots precisely and quickly. Ground Penetrating Radar (GPR), as an efficient and non-destructive geophysical technique, can non-destructively detect the information of soil roots. In this study, Pinus tabulaeformis root growth simulation experiment was conducted in the Caijiachuan River Basin of Jixian County, Shanxi Province, China using ground-penetrating radar. With the aid of the EKKO-Project software, the reflection wave parameters, wave velocity and time difference values of the ground-penetrating radar were extracted to establish a root diameter fitting model. The accuracy and reliability of three root diameter estimation methods, namely the reflection wave parameter method, the double-layer curve method and the three-dimensional depth slice method, under different depths, different root diameters and different antenna frequencies were comprehensively analyzed. The results showed that: (1) Among the four reflected wave parameters of GPR, total time interval (ΣT) and root diameter have the best fitting effect, R2=0.7233, P<0.05. (2) Among the three methods for estimating root diameters of ground-penetrating radar, when the antenna frequency is 500 MHz, the double-layer curve method has the best fitting effect (P<0.05). (3) The results of the three-dimensional depth slice root diameter fitting show that the detection and identification effect of the 1000 MHz frequency antenna is better than that of the 500 MHz antenna. The average relative errors between the actual root diameters and the estimated root diameters are 3.0 cm and 8.7 cm respectively, and the fitting reliability is poor. In conclusion, the accuracy of the three root diameter estimation methods based on ground-penetrating radar technology varies greatly. The double-layer curve method has the best accuracy for estimating the root diameters of Pinus tabulaeformis in the study area, and it can be used preferentially in practical applications.

Key words: ground penetrating radar, Pinus tabulaeformis, coarse root, root diameter estimation, loess area of Western Shanxi Province