The effects of soil bulk density, clay content and temperature on soil water content measurement using time-domain reflectometry
The effects of soil bulk density, clay content and temperature on soil water content measurement using time-domain reflectometry
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DOI：
10.1002/hyp.1358
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发表时间：
2003-12-30
影响因子：
3.2
通讯作者：
Sun, ZJ
中科院分区：
文献类型：
--
作者：
Gong, YS;Cao, QH;Sun, ZJ
由于时域反射法（TDR）具有非破坏性和受土壤质地、容重和温度影响小的特点，因此越来越多地用于田间土壤水分的测定。然而，随着仪器分辨率的提高，土壤容重和温度对TDR土壤水分测量的影响也有报道。这种影响主要是由土壤压实度和温度变化引起的土壤和水介电常数的变化引起的。本研究的目的是量化土壤容重和温度的影响，并提供相应的修正方法。在砂土、桑迪壤土、壤土和粘壤土中收集的数据表明，干土的介电常数的平方根与容重呈线性关系，并提出了容重修正公式。用该公式估算的土壤固体的介电常数与铝、硅、镁和钙的氧化物的介电常数接近。从桑迪壤土收集的数据显示，当土壤体积含水量高于0-30 m（3）m（-3）时，随着温度的升高，测量的土壤湿度显着降低。根据土壤温度和TDR测量的土壤湿度，建立了土壤湿度的温度修正方程。粘粒含量的影响已被检测到，但它不是统计学上显著的。高粘粒含量导致低水分区土壤含水量低估，高水分区土壤含水量高估。版权所有（C）2003约翰威利父子有限公司。
Time-domain reflectometry (TDR) is increasingly used for field soil water estimation because the measurement is non-destructive and less affected by soil texture, bulk density and temperature. However, with the increase in instrument resolution, the influences of soil bulk density and temperature on TDR soil moisture measurements have been reported. The influence is primarily caused by changes in soil and water dielectric permittivity when soil compaction and temperature varies. The objective of this study is to quantify the influence of soil bulk density and temperature, and to provide the corresponding correction methods. Data collected from sand, sandy loam, loam and clay loam show a linear relationship between the square root of dielectric constant of dry soil and bulk density, and a bulk density correction formula has been developed. The dielectric permittivity of soil solids estimated using this formula is close to that of oxides of aluminium, silicon, magnesium and calcium. Data collection from sandy loam show a noticeable decrease in measured soil moisture with increase in temperature when the volumetric soil water content is above 0-30 m(3) m(-3). A temperature-correction equation has been developed, which could provide the corrected soil moisture based on soil temperature and TDR-measured moisture. The effect of clay content has been detected, but it is not statistically significant. High clay contents cause the underestimation of soil water content in the low moisture range and overestimation of soil water content in the high moisture range. Copyright (C) 2003 John Wiley Sons, Ltd.