MP406 and MP306 ADR Standing Wave Technology Soil Moisture Sensors
The MP306/MP406 Soil Moisture Sensor is a robust, long term soil moisture measurement sensor that is unaffected by soil temperature or salinity, measuring volumetric water content using standing wave technology. It can be calibrated to provide accuracy within ±1%, and using the standard calibration curves ±3%.
Efficient irrigation scheduling and water management strategy require precisely measured soil water content.
Available in several configurations, and compatible with the ICT International IoT MFR Node, this sensor is suitable for deployment in both research and management projects:
- MP406: bare ended sensor, voltage output.
- MP306: bare ended sensor, voltage output; due to its needles arrangement is suitable for laboratory soil columns applications, or greenhouse pots.
- MP406C-12V: 4-20mA sensor, 12V.
- MP406C-24V: 4-20mA sensor, 24V.
- MPKit-406B or MPKit-306B: Portable Soil Moisture measurement kit, with Bluetooth connectivity.
- SNiP-MP4 or SNiP-MP3: IoT connected MP406 or MP306.
MP406 and MP306 Soil Moisture Sensor Features
- Volumetric Soil Water Content (%) or can simultaneously measure soil water potential
- Highly accurate and precise
- Robust, stainless steel needles and epoxy body
- Measures in saline, toxic and high temperature soils
- Rapid measurement
- Can be buried for up to 20 years
MPKit-406B and MPKit-306B Portable Soil Moisture Instant Reading Kit
A handheld, portable, soil moisture measurement system, the MPKit provides high quality and accurate data. The MPKit is a user-friendly tool, connecting the MP406 sensor (MPKit-406B) or the MP306 sensor (MPkit-306B) to an Android phone (included) using Bluetooth. Ideal for taking multiple soil moisture measurements, the MPKit is widely used. Commercial applications include irrigation monitoring of sports fields, agriculture, moisture control of concrete batch mixes or materials testing. Research applications are wide and varied, from frog ecology to soil carbon testing.
The MPKit records the volumetric soil moisture content, and optionally the location (using the phone’s GPS), for later analysis. The data is stored in a CSV file for easy analysis, with latitude, longitude, time & date recorded alongside volumetric soil moisture measurement.
Included with the MPKit is an Android phone with the ICT International MPKit app preinstalled. The app does not require an active SIM card to operate, only requiring Bluetooth and Location Services (GPS) to be enabled.
Within the app, it is a simple process to take a measurement; name the sample site and then take the measurement. This data will then be recorded in a CSV file which can be imported onto your computer for further analysis. Data can be visualised on a variety of software packages; the data can be imported into ArcGIS, QGIS or Google Earth as it has the required spatial data.
The Bluetooth unit attaches to the included handle and the sensor. The handle is made up of a straight section and a T handle section, allowing for easy insertion of the sensor’s needles and unit into the soil.
The Bluetooth unit will pair with an Android phone with the ICT International MPKit app installed. Supplied with 3x internal AAA batteries (user replaceable), the Bluetooth unit does not require charging.
Research papers using the MPKit are available here, whilst the research papers using the MP406 Soil Moisture Probe can be found here.
These sensors have a reinforced body and stainless steel needles making it ideal for use in extreme environments such as mine sites, landfills and saline soils as well as standard agricultural soils The measurements are not affected by temperature or salinity. Both MP406 or MP306 can be used to take continuous measurements over time through permanent or temporary burial and connection to an IoT Node
MP406 and MP306 use the standing wave principle of measurement. It is equivalent to a Time Domain Reflectometry (TDR) sensor without the need for a complex and expensive pulse generator; high accuracy, precision sensor with +/- 1%VWC accuracy following soil-specific calibration and 0.01%VWC resolution.
Accuracy
The results from measurement of absolute volumetric soil water percent (VSW%) from prepared soil samples using the MP406 are given above (Figure 1). This result is typical of the results obtained from comparative testing of the MP406 in prepared soil samples, for a wide range of agricultural soils.
Standing Wave Technology and hence the MP406 are not affected by changes in temperature or salinity of the soil or material being measured and hence the values of VSW% are equivalent to oven dried water content.
What is Standing Wave?
The standing wave technique uses an oscillator to generate an electrical field in order to detect the dielectric properties of a substrate of interest. The parallel needles of an MP406 act as a coaxial transmission line to generate a signal. The amplitude of the signal is related to the dielectric constant which in turn is directly related to moisture content.
Results
The results from measurement of absolute volumetric soil water percent (VSW%) from prepared soil samples using the MP406 are given alongside. This result is typical of the results obtained from comparative testing of the MP406 in prepared soil samples, for a wide range of agricultural soils. Standing Wave Technology and hence the MP406 are not affected by changes in temperature or salinity of the soil or material being measured and hence the values of VSW% are equivalent to oven dried water content.
MP406 | MP406C | |
Measurement | ||
Measurement Range | 0-100 VSW% | 0-100 VSW%</td |
Accuracy | +/- 1% | +/- 1% |
Resolution | 0.01% VSW% | 0.01% VSW% |
Response Time | Less than 0.5 seconds | Less than 0.5 seconds |
Stabilisation Time | 3 seconds approximately from power-up | 3 seconds approximately from power-up |
Interface | ||
Input Requirements | 7-18 V DC unregulated | ICTMP406C-12 System: 10.5V-18V
ICTMP406C-24 System: 14V-28V |
Power Consumption | 24 mA typical, 30mA max | |
Output signal for 0-100 VSW% | 0-1160mV | 4 to 20 mA |
Mechanical | ||
Total Length |
210 mm |
|
Needle Length |
60 mm |
|
Needle separation |
12 mm |
|
Needles |
Stainless Steel (Grade 316) – does not corrode in saline solutions |
|
Exterior |
ABS Plastic |
|
Cable |
4.5m Standard |