PR2 Profile Probe - analogue version

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PR2 Profile Probe Zoom
PR2/4 Profile ProbePR2 Profile Probe in the fieldPR2/6 Profile ProbePR2 Profile Probe with HH2 Soil Mositure Meter


"Soil moisture is an important parameter for many of the processes studied in our research – especially at depths below the immediate surface soil. For this reason we have been using the PR2 Profile Probe to measure moisture profiles down to one metre for many years. The PR2 measures soil moisture at varying depths on a total of 240 experimental plots across the Jena facility. The readings are taken on a weekly basis in the spring and summer, and on a bi‐weekly basis in the autumn and winter." Dr Anne Ebeling,
Scientific Coordinator at the Jena Experiment, Germany
(DFG-funded Research Unit)
  • Soil moisture content profiles down to 1m
  • Dual purpose – installed and portable
  • Uses access tubes for easy probe insertion and removal
  • SDI-12 interface option available

No other soil moisture probe system enables you to monitor your soil water profiles with such ease and flexibility. Install an access tube into the soil, insert the PR2 Profile Probe and press the HH2 [Read] button to display an instantaneous reading, or connect the PR2 to a data logger (GP2 or DL6) and leave the system to record soil moisture changes over time.

Video – Introduction to PR2 Profile Probe


The PR2 soil moisture probe is built around patented sensing technology which provides unprecedented performance in all soil types, with minimal influence from either salinity or temperature. The PR2/4 model measures soil moisture at 4 depths down to 40 cm – the PR2/6 measures at 6 depths down to 100 cm.

Both analogue and SDI-12 interfaces are available for the PR2. Click here for information on SDI-12 Profile Probes.


  • Highly reliable field-proven instrument
  • Soil moisture content – not just trends
  • Out of the box solution – supplied with calibrations for common soil types
  • Portable meter option for multi-site measurement

The PR2 Profile Probe is available in two sizes to measure to a depth of 40 cm or 100 cm.

The PR2/4 has sensing elements at 10/20/30/40 cm

The PR2/6 has sensing elements at 10/20/30/40/60 and 100 cm

HH2 Meter

The HH2 is a versatile readout unit that provides an easy and convenient way to display and store readings from Profile Probes. With the HH2 and PR2 combination, a probe can be moved from access tube to access tube, enabling large amounts of soil moisture data to be collected at multiple sites.

Data Logging

Profile Probes are available with analogue or SDI-12 outputs.
For the analogue version, order PR2/4 or PR2/6.
For the SDI-12 interface version, order PR2/4-SDI-12 or PR2/6-SDI-12.
Please note that analogue and SDI‐12 probes cannot be mixed on the same cable system

Loggers for analogue Profile Probes

Delta-T offers a choice of two data suitable data loggers. Both have dedicated PR2 Profile Probe input channels and connectors:
The DL6 Data Logger can log one PR2/6 or one PR2/4 Profile Probe
The GP2 Data Logger can log up to two PR2/6s or three PR2/4s

Loggers for SDI-12 Profile Probes

The PR2 SDI‐12 is ideally matched to the SDI‐12 enabled GP2 Data Logger. Many SDI-12 Profile Probes can be connected to a single GP2 (actual number depends on cable length, power, and other considerations).

Further details of the PR2 SDI-12 can be found here.

mcl-28-04-2011-16-17-25Augering and Extraction Kits – for optimal Access Tube installation

Profile Probes are used within access tubes inserted into augered holes in the soil – correct installation is vital for accurate measurement of soil moisture profiles. The goal of installation is to produce optimal contact between the soil and the wall of the access tube. The augered holes should be straight, smooth sided and the correct diameter.

Delta-T augering kits help you achieve the best possible access tube installation in virtually any soil.

Click here for information about our augering equipment





For Analogue PR2 and SDI-12 PR2

MeasurementVolumetric water content
Accuracy± 0.04 m3.m-3 (4%)
With soil-specific calibration
Soil moisture measurement rangeFull accuracy over:
0 to 0.4 m3.m-3
Full range : 0 to 1.0 m3.m-3
Salinity range50 to 400 mS.m-1
Salinity errors included in calibration
Temperature rangeFull accuracy over: 0 to 40°C
0 to 1.0 V
PR2/6: x6 outputs, PR2/4: x4

Power requirement(ANALOGUE)
5.5-15 V,
PR2/6: ~120 mA for 1s
PR2/4: ~80 mA for 1s
Minimum 7.5 V with 100 m cable
Power consumption <60 mA at 12 V DC
Sleep current <2 mA at 12 V DC
EnvironmentalIP67 (when installed in access tube)
Sample volume-95% sensitivity within a cylinder of diameter 200mm
Sample volume is weighted towards soil immediately surrounding the rods
Dimensions and weightPR2/6: length 1350 mm
PR2/4: length 750 mm
Both: 25.4 mm diameter
PR2/6: weight 1.2 kg
PR2/4: weight 0.8 kg
Sensor calibrationsIndividual sensors are interchangeable
Recalibration advised every 3 years (depending on use)
Soil calibrationsGeneralised Mineral and Organic soil calibrations are supplied

Product Resources

Data Sheets

Case Studies




Regulatory Information