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Study on TDR method : Measuring limitation and its applications

TDR方法研究：测量局限性及其应用

基本信息

批准号：
10460110
负责人：
CHIKUSHI Jiro
金额：
$ 8.83万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10460110/
关键词：
TDR Soil water Dielectric constant Volcanic soil Moisture sensor Irrigation Electrical conductivity Mixing model 火山伝導率水収支

项目摘要

The objectives of this study are to investigate the limitation of the TDR method to various soils, to examine the length of TDR probe, and to develop the application of the method We obtained the following results.1. A review of the TDR method disclosed various problems in terms of soil water measurements.2. Calibration experiments were conducted for three representative field soils in Kyushu Island. The results showed that the estimation by Topp's equation underestimates soil water content for smaller soil bulk density, and that the Maxwell-De Loor model as calibration equation can be successfully applied for different soils.3. A new type of TDR probe was designed using electrical circuit board. Calibration of the probe demonstrated its effectiveness in both dry and wet soil.4. Multiple length TDR probes of metal rods were employed to measure soil water content at different depths. The method was found to be applicable to determine the features of soil water distribution in field.5. Based on the fuzzy theory, we tried water saving control in a drip irrigation experimented in a dry land, and demonstrated the validity of the technique.6. Both soil water content and electrical conductivity were measured using TDR method for glass beads and sand soil. It was found that water content is higher in salt water condition than in distilled water condition, and that the Topp's equation excellently estimates soil electrical conductivity.7. The application of TDR method made it clear that the shading effect is independent of soil water content in mungbean cultivation, and that the water use efficiency is high in intercropping system.

本研究的目的是研究TDR方法在不同土壤中的局限性，考察TDR探针的长度，并拓展该方法的应用范围。对TDR方法的回顾揭示了土壤水分测量方面的各种问题。对九州岛三种具有代表性的田间土壤进行了定标试验。结果表明，在土壤容重较小时，Topp方程估计的土壤含水率偏低，Maxwell-de Loor模型作为校正方程可以成功地应用于不同土壤。利用电路板设计了一种新型的TDR探头。对探头的校准证明了其在干土和湿土中的有效性。利用多根金属棒TDR探头测量了不同深度的土壤水分。该方法适用于田间土壤水分分布特征的确定。基于模糊理论，在旱地滴灌试验中进行了节水控制试验，并验证了该技术的有效性。用TDR法测定了玻璃微珠和砂土的土壤含水率和电导率。结果表明，咸水条件下土壤的含水率高于蒸馏水条件下的水分含量，Topp方程较好地估计了土壤电导率。TDR法的应用表明，间作绿豆的遮荫效果与土壤水分无关，间作系统水分利用效率高。