Soil Water Potential Sensor

MODEL GEO-MPS2 - Maintenance-Free Water Potential and Temperature Sensor

Unlike tensiometers, which need a skilled operator, the dielectric water potential sensor model GEO-MPS2 needs no care or feeding. Instead, it can simply be packed into a hole, plugged into a data logger, and left to log water potential data.

GEO-MPS2 Maintenance-Free Water Potential and Temperature Sensor

Its extended range makes this sensor ideal for measuring the water potential in natural systems or other drier systems where cavitation of tensiometers is a concern. The added temperature measurements can be used to determine approximate soil water potential in partially frozen soils.


  • Deficit irrigation monitoring and control.
  • Water potential monitoring in the vadose zone.
  • Crop stress.
  • Waste water drainage studies.
  • Plant water availability.

The GEO-MPS-2 measures a wide range of soil water potentials (-10 to -500 kPa (pF 1.71 to pF 3.71) without user maintenance and factory calibration.

  • Accuracy Soil Water Potential: ± 25% of reading from -10 kPa to -100 kPa Soil Temperature: ± 1°C
  • Resolution Soil Water Potential: 0.1 kPa Soil Temperature: 0.1°C
  • Range Soil Water Potential: -10 to -500 kPa (pF 1.71 to pF 3.71) Soil Temperature: -40°C to 50°C
  • Measurement Speed 150 ms (milliseconds)
  • Equilibration time 10 min to 1 hr depending on soil water potential
  • Sensor Type Frequency domain with calibrated ceramic discs, thermistor
  • Output RS232 (TTL) with 3.6 volt levels or SDI-12 communication protocol
  • Operating Environment -40°C to 50°C
  • Power 3.6 - 15 VDC, 0.03 mA quiescent, 10 mA max during 150 ms measurement
  • Cable Length 5 m, custom cable lengths available
  • Cable Connector Types 3.5 mm "stereo" plug or stripped and tinned lead wires (3)
  • Sensor Dimensions 9.6 cm (l) x 3.5 cm (w) x 1.5 cm (d)
  • Warranty One year, parts and labor