The thermo-TDR (time domain reflectometry) technique has been applied for measuring soil bulk density (ρ_b) in-situ. However, the accuracy of thermo-TDR measured ρ_b data, as influenced by plant roots, has not been studied. In this study, we applied the extended de Vries heat capacity model to examine the influences of roots on thermo-TDR sensor performance for measuring ρ_b dynamics in the root zone. Soil samples were collected at multiple depths and horizontal positions over time during a maize growth period, and ρ_b values were determined gravimetrically and indirectly from thermo-TDR measurements. Results showed that by using the extended de Vries model, the thermo-TDR measured ρ_b agreed well with the gravimetric values. Ignoring root contribution to bulk soil heat capacity introduced 6.7%, 13.8% and 13.9% errors in thermo-TDR measured ρ_b data on the loamy sand, sandy loam, and clay loam soils, respectively. A critical root density of 0.037 g cm⁻³ was determined beyond which roots may induce ρ_b errors greater than 0.1 g cm⁻³ with the thermo-TDR technique.

热- TDR（时域反射）技术已被应用于用于测量土壤堆积密度（ρ _b原位）。然而，热TDR的精度测量ρ _b数据，通过植物的根作为影响，还没有研究。在这项研究中，我们应用了扩展德弗里斯热容量模型来研究根上热TDR传感器性能的影响，用于测量ρ _b在根区域动力学。土壤样品随时间多个深度和水平位置时的玉米生长期收集，ρ _b是从热TDR测量重量分析和间接地确定的值。结果表明，通过使用扩展德弗里斯模型，所述热TDR测量ρ _b与重量值非常吻合。到土体的热容量忽略根贡献在测量ρ热TDR引入6.7％，13.8％和13.9％的错误_b分别在壤质砂土数据，沙壤土，和粘土壤土。的0.037一个关键根密度克厘米^-3确定，超过该根可诱导ρ _b误差大于0.1g厘米更大^-3与热TDR技术。