10HS Soil Moisture Sensor

The 10HS measures the dielectric constant of the soil in order to find its volumetric water content (VWC). It obtains volumetric water content by measuring the dielectric constant of the media through the utilization of capacitance/frequency domain technology. Since the dielectric constant of water is much higher than that of air or soil minerals, the dielectric constant of the soil is a sensitive measure of volumetric water content. The 10HS has a low power requirement and very high resolution. This gives the ability to make many measurements (i.e. hourly) over a long period of time with minimal battery usage. In addition, the 10HS sensors incorporate a high frequency oscillation, which allows the sensor to accurately measure soil moisture in any soil with minimal salinity and textural effects.

An on-board voltage regulator allows factory calibrations to be used with any excitation voltage above 3V. In addition, the list of factory calibrations for the 10HS includes a dielectric calibration for use with the Topp Equation or other applicable dielectric to volumetric water content conversion equations.

10HS Soil Moisture Sensor Applications:

Irrigation scheduling
Vadose zone monitoring
Plant-soil-water interaction studies

Features:

Onboard voltage regulator allows the sensor to be powered with a wide range of excitation voltages (3-15 VDC) without changing the calibration
Large sensing (1100 cubic centimeters) allowing you to have a more representative measurement of soil VWC

Note:

The 10HS sensor is recommended for mineral soil applications where soil heterogeneity is a concern.
The 10HS sensor is not recommended for use with growing media such as Rockwool or Perlite, because the sensitivity of this sensor at dielectrics above 50 (approx. 57% VWC) drops significantly.

Specifications
Range:	Apparent dielectric permittivity (ε_a) : 1 (air) to 50 Soil volumetric water content : 0 – 0.57 m3/m3 (0 -57% VWC)
Accuracy:	(ε_a) : ± 0.5 from (ε_a) of 2 to 10, ±2.5 from (ε_a) of 10 to 50 (VWC) VWC: Using standard calibration equation: ± 0.03 m3/m3 (± 3% VWC) typical in mineral soils that have solution electrical conductivity < 10 dS/m Using soil specific calibration, ± 0.02 m3/m3 (± 2% VWC) in any soil
Resolution:	(ε_a): 0.1 from ea of 1 to 30, 0.2 from (ε_a) of 30 to 50 VWC: 0.0008 m3/m3 (0.08% VWC) in mineral soils from 0 to 0.50 m3/m3 (0-50% VWC)
Measurement Time:	10 ms (milliseconds)
Power requirements:	3VDC @ 12mA to 15 VDC @ 15 mA
Output:	300 – 1250 mV, independent of excitation voltage
Operating Temperature:	0 – 50 °C
Survival Temperature:	-40 to 50 °C
Connector types:	3.5 mm “stereo” plug or stripped and tinned lead wires
Cable length:	5 m standard
Datalogger Compatibility (non-exclusive):	Decagon: Em50, Em5b, ProCheck handheld reader. Other: Any data acquisition system capable of switched 3 to15 V excitation and single ended voltage measurement at 12 bit or better resolution
Dimensions:	14.5 cm x 3.3 cm x 0.7 cm

Links and Brochures
Download a printer-friendly version of 10HS Soil Moisture Sensor information (136K PDF)
Commercial-grade Data Logger System Em50 page
ProCheck hand-held readout device page
Soil Science Instrumentation page
Decagon Products Directory