The accuracy of soil water content measured by TDR depends on two key factors: soil dielectric constant and the calibration model of soil volumetric water content vs. dielectric constant.

时域反射仪测定土壤体积含水量的准确度取决于两个关键因素：土壤介电常数的测定准确度以及土壤含水量和介电常数之间的关系模型。

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Moreover, the relationship between dielectric constant and soil water content for two types of soil different from three empirical models due to organic matter or bulk density.

由于有机质或容重等因素的影响，另外两种土壤介电常数与含水量的关系与上述三个模型差别较大。

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Then the relationship between dielectric constant and volume water content or pore ratio of unsaturated soil was established. Different kinds of soil samples were tested.

在该模型的基础上研究了电磁波与非饱和土介质的相互作用，建立了非饱和土介质介电常数与体积含水量之间的关系模型。

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Engineers have found that wetlands, grassy fields and soil or sand filters can take in stormwater with different levels of pollution and release water with a relatively constant cleanliness.

VOA: standard.2010.08.04