土壤介电常数-含水量关系模型研究

Soil Moisture Content Detection with Ground-Penetrating-Radar and its Calibration Models of Soil Moisture Content vs.Dielectric Constant and its Measurement Accuracy

土壤含水量是农田灌溉管理的基础信息,传统测量方法费时费力,且破坏土壤原有结构。利用探地雷达测定土壤含水量具有快速连续、无损于土壤结构等优势。针对三种不同土壤,基于探地雷达反射波法,比较了常用的土壤介电常数-含水量模型,评估了探地雷达在不同类型土壤中的测量精度;针对砂土和粉土两种土壤,研究了雷达波平均振幅与含水量的关系。研究表明:六种土壤介电常数-含水量关系模型中,Malicki模型的估算精度最高,但需额外提供土壤干容重信息,Topp模型进行常数校正后可获得较好的预测精度;土壤含水量和振幅之间存在倒数关系,利用倒数模型可获得较高的含水量估算精度,在实际应用中应考虑土壤质地对模型具体形式的影响。

Soil water content is the fundamental information for irrigation management .The traditional measurement methods are tedi‐ous ,time-consuming and disturb the original soil structure .Ground penetrating radar is an accurate and non-destructive method to detect soil water content .This study investigated the measurement accuracy of radar reflection method in different soils ,and com‐pared several relationship models between soil dielectric constant and soil water content .The relationship between radar average am‐plitude and soil water content was studied in sandy and silty soil .The results showed that Malicki model has the highest estimation accuracy ,but it requires additional information on soil bulk density .Topp model is able to produce satisfactory estimation after cali‐bration .There is a reciprocal function between soil water content and average amplitude ,which can be used to derive soil moisture content .The expression of reciprocal function should be carefully determined according to the soil texture .