| Capacitance | Not only avoids corrosion of the probe but also gives a better reading of the moisture content of the soil as opposed to using resistive SMS
Since the contacts (the plus plate and the minus plate of the capacitor) are not exposed to the soil, there is no corrosion of the sensor itself
Response time is very fast
Remote access available
Very accurate after calibration
Can be used in moderate saline soils | Small sensing area
Affected by soil conditions - high salinity, clay content, and soil temperature
Site/soil specific calibration preferred | $10 - $350 per sensor\n$500 -$2,500 for data logger |
| TDR | Can be used without calibration to specific soils; however, it reduces accuracy
Not easily influenced by moderate saline soil conditions until the signal disappears
Can remain in soil through winter. Continuous measurements can be collected with data logger
Accurate with soil-specific calibration (2 - 3% error)
Easily expanded by multiplexing
Wide variety of probe configurations
Minimal soil disturbance | Need for good contact between sensor and soil
Small sensing area (2.4-inch diameter)
Might have limited applicability in highly saline or heavy clay soils
Calibration is needed for soils with tightly held water
Takes time to install because you must dig a trench rather than a hole
Uses a lot of power (large rechargeable batteries)
Soil-specific calibration required for soils having large amounts of bound water (i.e., those with high organic matter content) | $250 - $350 per sensor\n$1,000 - $3,500 for data logger |