Soil moisture - capacitance (EC-10)

Parameter to be measured:

Soil moisture

Method:

Capacitance

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Equipment:

• EC-5
• EC-10 (ECH₂O)
• EC-20

Advantages:

• Relatively cheap
• Easy to install
• Compatible with many loggers

Disadvantages:

• Only for low salinity soils (Decagon has developed newer ECH₂O probes that are less sensitive to salinity issues, e.g. the EC-5)
• Calibration needed
• Small measurement volume compared to other sensors

What to watch out for:

• Temperature sensitivity
• Careful installation, air gaps have a sustainable influence on the measurement compared to other sensors because of the small measurement volume

Links

Projects that used the above equipment:

• HYGRA – The effect of water storage variations on in-situ gravity measurements and their use for hydrology

Other related web sites:

• EC-5, EC-10, EC-20 Manual
• Calibration Equations or the ECH2O EC-5, ECH2O-TE and 5TE Sensors
• EC-5 Volume of Sensitivity
• USGS ECH2O calibration summary
• USGS ECH2O probe calibration protocol (destructive harvest)
• sowacs.com - the central resource for soil moisture measurement

References

• Bogena, HR; Huisman, JA; Oberdoerster, C; Vereecken, H. 2007. Evaluation of a low-cost soil water content sensor for wireless network applications. Journal of Hydrology, 344(1-2), 32-42, DOI: 10.1016/j.jhydrol.2007.06.032.
• Chanzy, A., Gaudu, J.-G., Marloie, O. (2012): Correcting the Temperature Influence on Soil Capacitance Sensors Using Diurnal Temperature and Water Content Cycles. Sensors 12, 9773-9790, DOI: 10.3390/s120709773.
• Saito, T; Fujimaki, H; Yasuda, H; Inoue, M. 2009. Empirical Temperature Calibration of Capacitance Probes to Measure Soil Water. SOIL SCIENCE SOCIETY OF AMERICA JOURNAL 73, 1931-1937, DOI: 10.2136/sssaj2008.0128.