Determining water content and bulk density: The heat-pulse method outperforms the thermo-TDR method in high-salinity soils
Determining water content and bulk density: The heat-pulse method outperforms the thermo-TDR method in high-salinity soils
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DOI：
10.1016/j.geoderma.2021.115564
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发表时间：
2021-11-08
期刊：
影响因子：
6.1
通讯作者：
Horton, Robert
中科院分区：
文献类型：
--
作者：
Peng, Wei;Lu, Yili;Horton, Robert
热脉冲法（HP）和热时域反射法（Thermo-TDR）可同时测定土壤热物性、含水量（θ）和容重（ρ B）。然而，它们在受盐影响的土壤上的性能仍然未知。本研究探讨了盐度对HP信号和热TDR测量的电磁波形，以及导出的θ和热性能值的填充土柱与各种质地，饱和度和体积电导率（σ a）的影响。还评估了用于估计rho B值的热TDR和基于HP的方法。结果表明：（1）当σ a值小于1.0dS m-1时，TDR法能提供可靠的θ，相对误差在5%以内，当σ a值大于1.0dS m-1时，由于TDR波形畸变，盐效应变得明显; TDR方法不能估计在σ a 7.59 dS m-1时的θ，而基于HP的方法能够从热性能测量中导出θ和ρ B值，θ的均方根误差在0.02 m3 m-3以内，rho B的均方根误差在0.12 Mg m-3以内。因此，HP为基础的方法优于热TDR的方法，用于确定在土壤中的θ和ρ B值与西格玛1.0 dS m-1。
Heat-pulse (HP) and thermo-time domain reflectometry (thermo-TDR) methods have been used to determine soil thermal properties, water content (theta) and bulk density (rho b) simultaneously. Their performances on salt-affected soils, however, remain unknown. This study investigated the effect of salinity on HP signals and thermo-TDR measured electromagnetic waveforms, and the derived theta and thermal property values of packed soil columns with various textures, saturations and bulk electrical conductivities (sigma a). The thermo-TDR and HP-based methods for estimating rho b values were also evaluated. The results showed that: (1) at sigma a values lower than 1.0 dS m-1, the TDR method provided reliable theta with relative errors within 5%; salt effects became apparent at sigma a values greater than 1.0 dS m- 1 due to the distortion of TDR waveforms; the TDR method failed to estimate theta at sigma a 7.59 dS m-1), and the HP-based approach was able to derive theta and rho b values from thermal property measurements, with root mean square errors within 0.02 m3 m- 3 for theta and within 0.12 Mg m- 3 for rho b. Thus, the HP-based approach outperformed the thermo-TDR approach for determining theta and rho b values in soils with sigma a 1.0 dS m-1.