物理介电特性差分解析土壤水分快速测定新方法

目前物理介电特性土壤水分测定研究主要集中在建立适应多土壤类型含水量测定的标定模型上，土壤中孔隙度对水分、土壤和空气三者之间物理介电特性影响问题亟待深入研究。本项目在团队前期已经明确土壤水分多参数调制技术机理基础上，深入分析土壤孔隙度引起介电特性变化规律，结合多年土壤物理化学性质现场测定工作经验，创新性提出物理介电特性参数差分解析法，拟开展以下研究工作：1)物理介电特性参数差分解析法水分测定基础理论；2)土壤含水量测定过程中温度变化不明显或呈单调性时，多相电容网络土壤传感器体系简化为当量并联结构，土壤物理介电特性参数差分解析消减土壤孔隙度等产生的测量误差；3)土壤、水分和空气三相依存下物理介电特性之间作用机制，揭示无需土类标定土壤水分信号快速获取规律。本项目从非匀质、多相和多孔土壤结构出发，解析不同孔隙度下土壤物理介电特性数学描述，为物理介电特性参数差分解析法土壤水分测定奠定理论基础。

Currently, dielectric properties based soil water content measurement mainly focus on how to eliminate the influence factors caused by the conductance in time-domain or frequency-domain method. Then calibration equations used for multiple soil types have been established for obtaining precise results of soil water content measurement. However, theoretical problems of soil porosity that produced by the physical interaction among water, soil and air need further to be understood and validated after analyzing the driving mechanism of soil porosity in both temporal and spatial domains. This project has been come up with an innovative idea, i.e. to implement the concept of parameter modulation of the frequency-domain capacitance soil water content sensor and dielectric properties involved soil water content measurement. Proposed research on this project: 1) accurate determination of soil water content using dielectric properties based differential parsing (DPDP) method; 2) the sensor system of soil water content in association with the multi-phase capacitance network can be simplified as an equivalent parallel structure when the changes in temperature are not obvious or monotonous during the measurement process of soil water content. The errors caused by soil type and soil porosity will be eliminated in the measurement of soil water content. 3) the mechanism of the physical interactions happened in dielectric properties of soil, water and air in soil sample, and rapid and accurate acquisition of soil water content signals without calibrations. This project will be initiated by the theory of heterogeneous, multi-phase and porous soil structure and the mathematical expressions of dielectric properties under different porosity. A novel theory of the DPDP method will be established and a novel approach will be put forward for the high-precision detection of water content of agricultural materials.