TR32-Database: Database of Transregio 32

[688] - Calibration of a Novel Low-Cost Soil Water Content Sensor Based on a Ring Oscillator

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Features
Citation
Qu, W., Bogena, H., Huisman, J. A., Vereecken, H., 2013. Calibration of a Novel Low-Cost Soil Water Content Sensor Based on a Ring Oscillator. Vadose Zone Journal, 12 (2), 1 - 10. DOI: 10.2136/vzj2012.0139.
Identification
Title(s):Main Title: Calibration of a Novel Low-Cost Soil Water Content Sensor Based on a Ring Oscillator
Description(s):Abstract: Wireless sensor networks are becoming more popular to monitor spatial and temporal variability of soil water content. The aim of this paper is to calibrate and test the newly developed SPADE sensor for wireless sensor network applications. During calibration, the measured sensor output is related to dielectric permittivity using an empirical calibration in liquids with well-defined permittivities. Using these calibration measurements, we have evaluated sensor-to-sensor variability and compared the accuracy of a universal calibration between sensor output and permittivity with a sensor-specific calibration. Our results showed that the sensor-to-sensor variability of the SPADE sensor is larger than sensor noise and that a sensor-specific calibration can improve the accuracy of soil water content estimation as compared to a single universal calibration. To quantify the effect of temperature on the sensor output, we have derived a temperature correction function in a temperature range from 5 to 40°C. The results showed an underestimation for low temperatures (5 to 25°C) and an overestimation for high temperatures (25 to 40°C). A second-order polynomial function was fitted to the measurements with good agreement (R2 = 0.9831, RMSE = 0.1489). The transferability of the temperature correction function from reference liquids to soils was verified using saturated coarse sand and a silty loam soil sample. The temperature-corrected SPADE sensor measurements in soil showed good agreement with TDR measurements and corresponded well with theoretical predictions from a dielectric mixing model.
Identifier(s):DOI: 10.2136/vzj2012.0139
Relation(s):Is Version Of: URL: http://www.tr32db.uni-koeln.de/data.php?dataID=1669
Responsible Party
Creator(s):Author: Wie Qu
Author: Heye Bogena
Author: Johan A. Huisman
Author: Harry Vereecken
Publisher:Soil Science Society of America
Topic
TR32 Topic:Soil
Related Sub-project(s):C1
Subject(s):CRC/TR32 Keywords: TDR, TDT, CRIM, Soil Water Content
File Details
File Name:2013_Qu_VZJ.pdf
Data Type:Text
Size(s):10 Pages
File Size:1670 kB (1.631 MB)
Date(s):Issued: 2013-05-02
Mime Type:application/pdf
Data Format:PDF
Language:English
Status:Completed
Constraints
Download Permission:OnlyTR32
General Access and Use Conditions:For internal use only
Access Limitations:For internal use only
Licence:TR32DB Data policy agreement
Geographic
North:50.6295048
East:6.3089068
South:50.6186145
West:6.2917406
Measurement Region:Kall
Measurement Location:Rollesbroich
Specific Informations - Publication
Status:Published
Review:PeerReview
Year:2013
Type:Article
Article Type:Journal
Source:Vadose Zone Journal
Issue:2
Volume:12
Number Of Pages:10
Page Range:1 - 10
Metadata Details
Metadata Creator:Wei Qu
Metadata Created:2013-12-02
Metadata Last Updated:2013-12-02
Subproject:C1
Funding Phase:2
Metadata Language:English
Metadata Version:V40
Dataset Metrics
Page Visits:179
Metadata Downloads:0
Dataset Downloads:6
Dataset Activity
Features