土质对FDR水分传感器拟合参数影响的试验研究

Experimental Research on Effect of Soil Texture on Fitting Parameters of FDR Moisture Sensors

通过制作人工土柱的方法,对壤土、黏土、砂土等土质进行FDR（Frequency Domain Reflectometry）水分传感器拟合标定试验,分析了传感器频率与土壤水分之间的关系,以及不同质地土壤对传感器标定参数的影响。数据分析结果表明：FDR土壤水分传感器感应频率随土壤体积含水量的增加而单调减小,具有很好的相关性,不同的土质对土壤水分传感器标定参数影响较大,黏土测试的传感器归一化频率范围在0.64~0.94之间,壤土测试的传感器归一化频率范围在0.4~0.86之间,砂土测试的传感器归一化频率范围在0.3~0.94之间,土壤按类别进行标定比集中标定的效果更好。分析结果对土壤种类复杂地区的自动土壤水分观测仪精细化标定具有一定指导意义。

With the method of artificial soil columns, several kinds of soil, such as loam, clay, and sandy soil, were used in the FDR （Frequency Domain Reflectometry） moisture sensor calibration experiment to analyze the relationship between sensor frequency and soil moisture. The effects of soil textures on calibration parameters are studied through calibration experiments on different kinds of soil. The results show that the frequency of the FDR soil moisture sensor is monotonously decreasing with the increase of soil volumetric water content; the correlation is obvious, and different kinds of soil affect moisture sensor parameters remarkably. The normalized frequency of the sensor for clay testing ranges between 0.64 and 0.94, loam between 0.4 and 0.86, soil between 0.3 and 0.94. A better result is obtained in classification calibration than in concentration calibration. The experimental results have significance for the fine calibration of automatic soil water detectors in the areas with complex soil.