Application of Evaporation Method Using Two Tensiometers for Determining Unsaturated Hydraulic Conductivity beyond Tensiometric Range
Application of Evaporation Method Using Two Tensiometers for Determining Unsaturated Hydraulic Conductivity beyond Tensiometric Range
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DOI：
10.1134/s1064229319040069
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发表时间：
2019-04
影响因子：
1.4
通讯作者：
H. Fujimaki;A. Yanagawa
中科院分区：
文献类型：
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作者：
H. Fujimaki;A. Yanagawa
准确测定低水头范围内的非饱和导水率对于预测局部灌溉条件下的蒸发速率或干旱胁迫条件下的根系吸水是至关重要的。我们提出了一个相对低成本和快速的实验室方法，同时确定保水和水力传导率的功能在很大范围的压头。该方法与使用两个张力计的常规蒸发法非常相似。除了张力计读数外，所提出的方法还使用末端的含水量分布和累积蒸发。对3种不同质地土壤的试验结果表明，反演优化得到的导水率函数与稳态蒸发法测得的K值吻合较好，表明了该方法的可靠性。用坎贝尔的K（θ）函数拟合的K值与参考值也吻合较好，但与参考值有较大的偏差。这说明在低压水头范围内K（θ）的实测是十分重要的。
AbstractAccurate determination of unsaturated hydraulic conductivity in low pressure head range is critical for predicting evaporation rate under localized irrigation or root water uptake under drought stress conditions. We proposed a relatively low cost and fast laboratory method to simultaneously determine water retention and hydraulic conductivity functions across a wide range of pressure heads. The method is quite similar to conventional evaporation method using two tensiometers. In addition to tensiometer readings, the proposed method uses water content profile at the end and cumulative evaporation. Experimental results for three soils with different textures showed that inversely optimized hydraulic conductivity functions agreed with K-data measured with the steady state evaporation method, indicating the reliability of the proposed method. The hydraulic conductivity functions fitted forK-data obtained by tensiometer readings with Campbell’sK(θ) function also agreed well with the referenceK-data for two of the three soils, but largely deviated from those for the third soil. This indicates the importance of actual measurement ofK(θ) in low pressure head range.