This is the first of two articles that present experimental spectra of six soil samples with varying clay contents ranging from 0% to 55% and organic carbon levels ranging from 0% to 3.9%, measured at a small step of moisture change at a temperature of 25 °C. The study was carried out using a method that enables the measurements of the same sample over a wide frequency range of 1 kHz–8.5 GHz and in some cases up to 20 GHz. The relative effective complex permittivity (RCP) is strongly influenced by dielectric relaxation processes due to the Maxwell–Wagner (MW) effect in the frequency range of 10 kHz–8.5 GHz as demonstrated. These processes are aided by the presence of clay in the soil. Up to frequencies of 4–5 GHz, these processes have a weak influence, mainly on the imaginary part of the RCP. This explains why in the dielectric models of Dobson and Mironov, where relaxation processes are ignored, free and physical bound water has high specific conductivity. We demonstrated that organic carbon, even at low content, reduces the real and imaginary parts of the RCP when all other factors are equal. Part II will present the results of using the Debye and Cole–Cole formulas to model relaxation processes.

中文翻译：

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介电弛豫过程对 10 kHz 至 8 GHz 频率下土壤复介电常数的影响——第一部分：实验

这是两篇文章中的第一篇，它们展示了六个土壤样品的实验光谱，这些土壤样品的粘土含量从 0% 到 55% 不等，有机碳含量从 0% 到 3.9% 不等，在温度为25°C。该研究是使用一种方法进行的，该方法能够在 1 kHz-8.5 GHz 的宽频率范围内测量同一样品，在某些情况下甚至高达 20 GHz。如图所示，由于麦克斯韦-瓦格纳 (MW) 效应在 10 kHz-8.5 GHz 频率范围内，相对有效复介电常数 (RCP) 受到介电弛豫过程的强烈影响。土壤中粘土的存在有助于这些过程。在 4-5 GHz 频率范围内，这些过程的影响很小，主要是对 RCP 的虚部。这解释了为什么在忽略弛豫过程的 Dobson 和 Mironov 介电模型中，自由和物理结合水具有高比电导率。我们证明，当所有其他因素都相同时，有机碳即使含量很低，也会减少 RCP 的实部和虚部。第二部分将介绍使用 Debye 和 Cole-Cole 公式模拟松弛过程的结果。