不同水分传感器在河北平原典型土壤中的测量准确度对比

Accuracies of soil moisture sensors in typical soils in the Hebei Plain

深入了解不同类型土壤传感器的性能表现对于提高区域土壤含水量测定的准确性具有重要意义。本研究针对河北平原农田土壤,选择了4种典型土壤质地(粉黏土、粉壤土、砂壤土、砂土),通过室内试验,分别研究了5个不同容重(1.40 g∙cm^(−3)、1.45 g∙cm^(−3)、1.50 g∙cm^(−3)、1.55 g∙cm^(−3)、1.60 g∙cm^(−3))下5种常见土壤水分传感器(TDR315H、CS655、5TE、Teros12、Hydra ProbeⅡ)测定含水量的准确度。研究发现:1)在本试验条件下,未经标定的TDR315H、CS655、Teros12、Hydra ProbeⅡ的测量准确度较高,测量误差基本不超过0.03 cm^(3)∙cm^(−3),其中TDR315H的性能表现最好;2)5种类型传感器在粗质土壤中的误差大于细质地土壤,土壤质地对传感器测量准确度的影响远大于土壤容重;3)土壤含水量对传感器的测定准确度也会产生显著影响,随着含水量的变化,测量误差也随之发生变化,且可能存在使传感器测量准确度发生显著变化的含水量阈值。总体而言,在未进行标定的前提下,TDR315H有望直接应用于河北平原农田田间土壤含水量监测。本研究可为土壤含水量监测中的传感器选型提供重要参考。

Soil moisture is an essential factor for the growth of crops and plants,and the measurement of soil moisture is the basis of research on agriculture,hydrology,environment,and soil and water conservation.Compared with traditional methods of soil mois-ture measurement,the main measurement methods currently used are different types of soil moisture sensors.Research on soil moisture sensors is mostly based on the comparative study of foreign soil,and research on the adaptability of sensors by foreign manufacturers in domestic soil is limited.The factors considered in previous studies are usually limited to soil temperature,soil salinity,and soil texture types,and few texture types have been considered.Thus more research is required on more factors and soil texture types.An in-depth understanding of the performance of different types of soil sensors is crucial for improving the accuracy of regional soil water content measurements.Therefore,to explore the measurement performance of different types of sensors in typical soils of the Hebei Plain,five types of soil moisture sensors that are widely used worldwide were selected in this study,and the influence of soil texture and bulk density on their measurement accuracy was investigated.Four typical soil textures(silty clay,silt loam,sandy loam,and sand)were selected to study the accuracy of five common soil moisture sensors(TDR315H,CS655,5TE,Teros12,and Hydra ProbeⅡ)under five different bulk density conditions(1.40 g·cm^(−3),1.45 g·cm^(−3),1.50 g·cm^(−3),1.55 g·cm^(−3),and 1.60 g·cm^(−3)).The results showed the following:1)Under the experimental conditions,the measurement accuracy of uncalibrated TDR315H,CS655,Teros12,and Hydra ProbeⅡwas high,the measurement error was less than 0.03 cm^(3)·cm^(−3),and the performance of TDR315H was the best.2)Generally speaking,the errors of five types of sensors in coarser soil were greater than those in finer soil,and the influence of soil texture on the measurement accuracy of sensors was far greater than that of soil bulk density.3)The soil moisture content also had a significant impact on the accuracy of the sensor.With a change in soil moisture content,the measurement error also changed,and there may be a threshold of soil moisture content(such as 0.3 cm^(3)∙cm^(−3)in this study)that made the measurement accuracy of the sensor change significantly.In general,without calibration,TDR315H is expected to be directly applied in field measurements of soil water content in agricultural land in the Hebei Plain.This study provides an important reference for sensor selection in soil moisture monitoring.