Measurement: Water Potential

HYPROP

Generate detailed moisture release curves on undisturbed soil samples in a standard 250 mL sample ring, typically within a few days. HYPROP also determines unsaturated hydraulic conductivity values for the soil sample.

Benchtop Instruments

Water potential describes the force that drives water movement. It is the most fundamental and essential measurement in soil physics. Unfortunately, it's also a tricky thing to measure. The chart on the right (click on it to view the full image)…

MPS-6 Calibrated Water Potential Sensor

  • Water potential range -9 to -100,000 kPa
  • Accuracy (10% + 2 kPa)
  • No refilling or field maintenance necessary
  • Plug and play with Decagon data loggers, digital output SDI-12 for non-Decagon data loggers

MPS-2 Dielectric Water Potential

  • Lowest cost option for measuring field water potential
  • Water potential range -9 to -100,000 kPa
  • Accuracy (25% + 2 kPa)
  • No refilling or field maintenance necessary
  • Plug and play with Decagon data loggers, digital output SDI-12 for non-Decagon data loggers

Vapor Sorption Analyzer

The Vapor Sorption Analyzer (VSA) brings click and read efficiency to soil water characteristic curves. In 24 to 48 hours, the VSA generates up to 200 data points (water potential vs. water content) for both adsorption and desorption. The VSA works in the dry (-10 to -475 MPa) range. You can create automated soil-water characteristic curves and generate all the correlations with clay activity, surface area, and swelling potential. With the new static feature, you can hold humidity constant and look at the way soil takes up water into its crystal structure (2:1 clays) and monitor water content change over time.

T4 Field Tensiometer

  • Water potential range +100 to -85 kPa
  • Highly accurate ( +/- 0.5 kPa)r
  • External refilling makes this a suitable sensor for continuous field measurements.
  • Analog (voltage) output

T5 Laboratory Tensiometer

  • Water potential range 0 to -85 kPa (extended range up to -250 kPa with T5x)
  • Highly accurate ( +/- 0.5 kPa)
  • Best suited for laboratory or spot measurements of water potential..
  • Analog (voltage) output

WP4C Water Potential Meter

Fast, Accurate Water Potential Measurements Use the WP4C to measure water potential in 5 to 10 minutes.  Range: -0.1 to -300 MPa* Versatile The WP4C can be used to measure the water potential of any porous material.  It's typically used to analyze…

T8 External Refilling Field Tensiometer

  • Water potential range +100 to -85 kPa w/ temperature measurement
  • Highly accurate ( +/- 0.5 kPa)
  • External refilling makes this a suitable sensor for continuous field measurements.
  • Digital output SDI-12 and RS-485

TS1 Smart Tensiometer

  • Water potential range +100 to -85 kPa w/ temperature measurement
  • Highly accurate ( +/- 0.5 kPa)
  • Automated refilling for low maintenance
  • Digital output SDI-12 and RS-485

Soil Moisture Release Curve Construction

Decagon's Soil Moisture Release Curve service uses UMS tensiometers and the HYPROP to produce the points for the moisture characteristic curve in the wet range, and the WP4C to produce the points in the dry range. Your soil moisture characteristic curve service is specific for the soils that you send to Decagon, and are over the range that you specify.