Soil moisture - capacitance (TMS)

Longitudinal view on TMS probe

View on installed TMS probe

Parameter to be measured:

Soil moisture, soil, surface and air temperature

Method:

Capacitance

Equipment:

• temperature measurement with sensor MAXIM/DALLAS Semiconductor DS7505U+, with resolution of 0.0625 °C and with accuracy of ±0.5 °C
• soil moisture measurement based on capacity technique in the frequency of 100-200MHz
• integrated data loggers of 32MBit

Advantages:

• stand alone system
• cheap
• Easy to install

Disadvantages:

• Calibration needed
• Small measurement volume compared to other sensors
• Actual Software is less comfortable
• Connection between readout unit and probe can be improoved

What to watch out for:

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

Price:

80 € (2013, Europe)

Links

Projects that used the above equipment:

• COMTESS
• TERENO

Other related web sites:

• TOMST®
• TMS3 TOMST Measuring System - Station for spatially distributed measurements of soil moisture and ambient temperature in vast fields
• TMS software and calibration set for typical soils
• Design and calibration of modular autonomous station for the measurement of soilmoisture and temperature conditions in vast point clusters

References

• Wild, J., Kopecký, M., Zmeškalová, J., Hadincová, V., Trachtová, P., Nováková, O., Štípek, A., Šanda, M., Haase, T., Field monitoring of microclimate: new combined thermal and soil moisture standalone unit
• Hernández, J.A.C. et al., 2013. Unsaturated volcanic tephra and its effect for soil movement in El Salvado. Earth Science 2(2), 58-65, DOI: 10.11648/j.earth.20130202.1
• Světlíková, P., 2012. Impact of local heat leakage on vegetation and participation of non-native species. Master thesis, České Budějovice, CZ