基于介电原理的浅层土壤水分测量方法研究

发布时间：2019-01-08 19:27

【摘要】：土壤水分是农业科学、水文科学和气象科学等领域的重要参数。针对当前土壤水分传感器只能测量特定深度以下土壤水分的不足,该文从土壤的介电特性入手,尝试将深埋式土壤水分传感器迁移至浅层土壤(5cm厚土层)中进行水分测量。通过改善探针结构,有效实现了浅层土壤水分测量。该研究的内容及主要成果如下：为了将深埋式介电原理土壤水分传感器迁移至浅层5cm土壤的水分测量中,该研究对锥形探针进行改良,提出一种平行探针结构。为了验证所提出探针结构的合理性,应用三维电磁仿真软件HFSS对探针、探针—土壤系统进行电磁仿真；并对仿真模型求解,分析探针阻抗变化情况。HFSS模型求解的理论结果显示,平行探针结构能够通过含水土壤实现电磁耦合,可以用于浅层5cm土壤水分的表面测量。同时,HFSS求解的理论结果还表明,传感器的灵敏程度将随着探针长度L和探针间距d的增大而分别减小。为了验证上述分析,设计有机溶液实验和烘干法实验。在此之前,通过控制变量法,验证了探针参数对传感器灵敏程度的影响。有机溶液实验结果表明制作的FD浅层土壤水分传感器的输出能够在一定程度上代表土壤中的水含量。烘干法则通过对5cm土层的实际测量,证明了介电理论应用于土壤水分表面测量的可能。这一结果是对深层土壤水分测量的补充。
[Abstract]:Soil moisture is an important parameter in agriculture, hydrology and meteorology. In view of the deficiency that soil moisture sensor can only measure soil moisture below specific depth at present, this paper attempts to transfer the deeply buried soil moisture sensor to shallow soil (5cm thick soil) to measure soil moisture from the dielectric properties of soil. By improving the probe structure, the shallow soil moisture measurement was realized effectively. The contents and main results of this study are as follows: in order to transfer the deep buried dielectric principle soil moisture sensor to the shallow 5cm soil moisture measurement, this study improved the conical probe and proposed a parallel probe structure. In order to verify the rationality of the proposed probe structure, the electromagnetic simulation software HFSS was used to simulate the probe and the probe soil system. The theoretical results of HFSS model show that the parallel probe structure can be coupled by electromagnetic coupling through water-bearing soil and can be used for surface measurement of shallow 5cm soil moisture. At the same time, the theoretical results of HFSS solution also show that the sensitivity of the sensor decreases with the increase of probe length L and probe spacing d. In order to verify the above analysis, organic solution experiments and drying experiments were designed. Prior to this, the influence of probe parameters on the sensitivity of the sensor was verified by the control variable method. The experimental results of organic solution show that the output of the FD shallow soil moisture sensor can represent the water content in the soil to a certain extent. Through the actual measurement of 5cm soil layer, the possibility of applying dielectric theory to the measurement of soil moisture surface is proved. This result is complementary to the measurement of deep soil moisture.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7;TP274

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