Soil moisture/Electric Conductivity - FDR (WET Sensor)

Parameter to be measured:

Soil moisture, permitivity Indirect measurement of electric conductivity of pore water

Method:

Frequency Domain Sensor

Equipment:

• Delta-T Device: WET Sensor with 3 rods of 600 mm length, HH2 display for manual reading or a data logger

Advantages:

• easy and fast measurement of punctual soil moisture and electric conductivity of soil pore water
• manual as well as continuously logged measurements possible

Disadvantages:

• Each sensor has to be calibrated
• careful application of probe in stony soils
• Underestimating of permitivity in media with low permitivity (ε > 40, clay and organic soils)
• unaccurate values in saturated media

What to watch out for:

• Good contact between probe and medium has to be proved

Links

Other related web sites:

• Delta-T Devices: [1]

References

Hamed, Y.,Samy, G., Persson, M. (2006), Evaluation of the WET sensor compared to time domain reflectometry, HYDROLOG SCI J 51(4),671-681.

Regalado, C.M., Ritter, A., Rodriguez-Gonzalez, R.M. (2007), Performance of the commercial WET capacitance sensor as compared with time domain reflectometry in volcanic soils, VADOSE ZONE J 6(3), 1539-1663.

Bouskila, F.,Persson, M., Berndtsson, R., Bahri, A. (2008), Soil water content and salinity determination using different dielectric methods in saline gypsiferous soil, HYDROLOG SCI J 53(1), 253-265.