HydraProbe – Soil Moisture Probe

The HydraProbe – Soil Moisture Probe from the Stevens Water range. A rugged soil moisture sensor with patented technology. Provides continual and consistent accuracy to measure the three most significant soil parameters simultaneously – soil moisture, salinity and temperature.

 

The HydraProbe is the most scientifically researched soil moisture sensor available. Several US Government agencies depend on it daily to deliver soil moisture data they can trust. In fact, every HydraProbe Soil Moisture Logger comes with a 5 or 10 year guarantee.

 

The HydraProbe is also ideal for remote monitoring with our Data Collection telemetry systems. This soil moisture logger is able to connect to any system that is RS485 or SDI-12 compatible. The HydraProbe, and other soil moisture sensors all link with our vanwaltDataHub and vanwaltDataSlave telemetry systems to deliver your soil moisture data directly to your desktop. Networks of soil moisture sensors can wirelessly feed into a central point, with data delivered to whoever needs to see it. A system continuously running without the need to go onsite to collect your readings.

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Advantages

The most scientifically researched soil sensor on the market, it is used extensively by the United States Department of Agriculture (USDA), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), many of the World’s leading irrigation companies and Universities for more than 20 years. It’s been engineered by Stevens Water to be exceptionally rugged and will provide data that you can trust year after year. We are so confident in the technology: every HydraProbe comes with a 5 or 10-year guarantee.

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HydraProbe – Soil Moisture Probe

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HydraProbe – Soil Moisture Probe Equipment Options:

Applications

  • Agriculture
  • Soil health studies
  • Soil Research
  • Crop irrigation research & optimisation
  • Irrigation optimisation studies
  • Research into crop yields
  • Water conservation research
  • Water saving & water protection studies
  • Sports turf research
  • Soil erosion prediction models
  • Environmental modelling studies
  • Flood forecasting
  • Biofuel production
  • Reservoir recharge investigations
  • Soil carbon sequestration studies
  • Watershed hydrology studies
  • Landslide studies

Options

HydraProbe Standard
HydraProbe Pro
HydraProbe Pro-ET
Output
VWC (% Moisture)
Temperature (C / F)
VWC (% Moisture)
Soil Conductivity
Soil Conductivity (comp)
Real Permittivity
Real Permittivity (comp)
Imaginary Permittivity
Imaginary Permittivity (comp)
Temperature (C / F)
Pore Water EC
Permittivity
No Outputs
All Outputs
Soil Calibrations
General
Organic
Rockwool
General
Organic
Rockwool
Custom
Measurement Commands
Support aM and aC (but not aM# and aC#)
Support all aM# and aC#
Extended Commands
Not support aXM andaXW
Support all aXM andaXW
Conformance Certificate
Factory
Factory + NIST
Warranty
5 Years
10 Years
Temperature Range
-10 to 60
-10 to 60
-30 to 65

Each HydraProbe is available with cable lengths of:

Cables
Length
7.7 m (25 ft.)
15.25 m (50 ft.)
30.5 m (100 ft.)

Each HydraProbe is available with SDI-12 or RS485 Connectivity

Specifications

HydraProbe Pro
Measurement
Accuracy
Range
Resolution
Real dielectric permittivity (isolated)
1 to 80 where 1 = air, 80 = distilled water
0.001
Soil moisture for inorganic & mineral soil
± 0.01 WFV for most soils
± 0.03 max for fine textured soils*
From completely dry to fully saturated (from 0% to 100% of saturation)
0.001
Bulk electrical conductivity
± 2.0% or 0.02 S/m whichever is typically greater
0 to 1.5 S/m
0.001
Temperature**
± 0.3°C
-10°C to +60°C
0.1°C
Inter-sensor variability
3 m-3)
n/a
* Accuracy may vary with some soil textures.
** For standard extended temperature range and extra extended temperature range probes, contact us for details.
Electrical
SDI-12
RS-485
Power supply
9-20 VDC
9-20 VDC
Power consumption
Cable
3-wire: power, ground, data
4-wire: power, ground, com+, com-
Max. cable length
60 m
1,219 m Non-spliced: 304.8 m
Baud Rate
1200
9600
Communication protocol
SDI-12 Standard v. 1.2
Custom or open spec
Addressing
Serial; allows multiple sensors to be connected to any RS485 or SDI-12 data logger via a single cable.
Environmental
Operating temperature range
Standard temperature probe range: -10°C to +60°C
Standard extended temperature probe range: -30°C to 60°C**
Extra extended temperature probe range: -40°C to 65°C**
Storage temperature range
-40°C to +65°C
Water resistance
Tolerates continuous full immersion
Cable
18 gauge (22 gauge for RS-485 version), UV resistant, direct burial
Vibration and shock resistance
Excellent; potted components in PVC housing and 304 grade stainless steel tines
** For standard extended temperature range and extra extended temperature range probes, contact us for details.
Physical
Length
124 mm
Diameter
42 mm
Weight
200 g
Optional slim housing version available (184 g)
Cable weight
80 g/m
Sensing Volume (cylindrical region)
Length: 5.7 cm
Diameter: 3.0 cm
Measurement Parameters
1
Voltage 1
2
Voltage 2
3
Voltage 3
4
Voltage 4
5
Voltage 5
6
Soil Temperature in Celsius
7
Soil Temperature in Fahrenheit
8
Water fraction by volume
9
Loss Tangent
10
Soil Conductivity (temperature corrected) in Siemens / meter
11
Real dialectric permittivity
12
Real dielectric permittivity (temperature corrected)
13
Imaginary dialectric permittivity
14
Imaginary dialectric permittivity (temperature corrected)
15
Soil conductivity in Seimens / meter
16
Diode Temperature in Celsius
17
Saved for future development
18
ADC Reading 1
19
ADC Reading 2
20
ADC Reading 3
21
ADC Reading 4
22
ADC Reading 5

Scientific Studies

Main Author
Publication Date
Journal Reference
Application
Title/Link:
Dielectric Loss and Calibration of the HydraProbe Soil Water Sensor
Seyfried, M. S.
2005
Seyfried, M. S., L. E. Grant, E. Du, and K. Humes, Dielectric Loss and Calibration of the Hydra Probe Soil Water Sensor, Vadose Zone Journal 4:1070–1079 (2005).
Derivation of the HydraProbe’s general soil moisture calibration
Title/Link:
Estimating root zone soil moisture at distant sites using MODIS NDVI and EVI in a semi-arid region of southwestern USA
Schnur, M. T.
2010
Ecological Informatics. doi:10.1016 / j.ecoinf.2010.05.001
Using HydraProbe soil sensor to assess regional effects on vegetation and root zone soil moisture in arid lands.
Title/Link:
The NOAA Hydrometeorology Testbed Soil Moisture Observing Networks: Design, Instrumentation, and Preliminary Results
Zamora, R. J.
2011
Journal of Atmospheric and Oceanic Technology, 28, 1129-1140. doi:10.1175 / 2010JTECHA1465.1
Using HydraProbe to forecast floods and assess flood risk.
Title/Link:
Evaluation of Lichtenecker’s Mixing Model for Predicting Permittivitty of Soil at 50 MHz
Leao, T. P., E. P.
2015
American Society of Agricultural and Biological Engineers, 58(1), 83-91. doi:10.13031 / trans.58.10720
Dielectric Mixing and dielectric permittivity of heterogeneous materials.
Title/Link:
Soil Moisture for Hydrological Applications: Open Questions and New Opportunities
Brocca, L. C.
2017
Advances in Hydro-Meteorological Monitoring, Special Issue of Water, 9(140). doi:10.3390 / w9020140
Soil Moisture and its effect on climate, drought and regional weather.
Title/Link:
Climate Models Predict Increasing Temperature Variability in Poor Countries
Bathiany, S. V.
2018
Science Advances, 4(5). doi:10.1126 / sciadv.aar5809
Using soil moisture measurements to make improved climate models.

Resources

Manuals & Downloads

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+44 (0) 1428 661 660 +64 (0)3443 5326 +27 21 518 1347