SNiP-MP3 For Soil Moisture
The SNiP-MP3 is a 'Sensor Node Integrated Package' for LoRaWAN or CAT-M1 communication of real-time accurate soil moisture measurements for continuous soil monitoring.
SNiP-MP3
The base SNiP-MP3 integrates 1x MFR-NODE and 1x MP306 soil moisture probe to a site’s unique network, communication and power requirements. The MFR-NODE can support an added 3x MP306 soil moisture probes to monitor soil moisture at multiple depths.
The MP306 provides a measurement on the absolute Volumetric Soil Water % (VSW), based on the Standing Wave, or Amplitude Domain Reflectometry (ADR) measurement principle.
See Further Specifications on the MFR-NODE
Extended SNiP-MP3
Alternatively, an extended SNiP-MP3 can be customised to include sensors that measure
- other soil parameters (such as the Jet-Fill Tensiometer [with matching Transducer]),
- plant monitoring parameters (such as the DPS40 Pivot Stem Dendrometer, DBS60 Dendrometer, Therm-Micro Leaf Temperature Sensor)
- environmental parameters (such as the SRG0 Stainless Steel Rain Gauge)
MP306 uses 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. MP306 is a high accuracy, precision sensor with 1% VWC accuracy following soil-specific calibration and 0.01% VWC resolution.
The MP306 is ideally supported by the SMM Soil Moisture Meter, a wireless, stand-alone logging instrument available from ICT International. With the SMM, MP306 sensors can be individually calibrated for maximum accuracy.
- The SMM can support up to 5 MP306 sensors.
- For complete monitoring solutions, the MP306 is used in combination with the MP406 soil volumetric moisture content sensor, tensiometers for soil water potential, ICTO2 soil oxygen sensor, or the ICT International automatic weather station.
MP306 Accuracy
The results from measurement of absolute volumetric soil water percent (VSW%) from prepared soil samples using the MP306 are given below (Figure 1). This result is typical of the results obtained from comparative testing of the MP306 in prepared soil samples, for a wide range of agricultural soils. Standing Wave Technology and hence the MP306 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 MP306 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 MP306 are given below. This result is typical of the results obtained from comparative testing of the MP306 in prepared soil samples, for a wide range of agricultural soils. Standing Wave Technology and hence the MP306 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.
Polynomial Look-up Table
Linearisation tables can be added to Data Loggers using the following data:
Converting Data Table for MP-306. From VSW% to mV & mA in mineral soil
| VSW% | mV MP306 | mA MP306C |
|---|---|---|
| 0% | 0 | 4.00 |
| 2% | 120 | 5.71 |
| 5% | 210 | 6.99 |
| 10% | 310 | 8.43 |
| 15% | 415 | 9.93 |
| 20% | 510 | 11.285 |
| 25% | 610 | 12.71 |
| 30% | 720 | 14.285 |
| 35% | 825 | 15.785 |
| 40% | 895 | 16.785 |
| 45% | 955 | 17.64 |
| 50% | 1005 | 18.35 |
| 55% | 1015 | 18.5 |
| 60% | 1025 | 18.64 |
| 65% | 1035 | 18.785 |
| 70% | 1045 | 18.93 |
| 75% | 1055 | 19.07 |
| 80% | 1065 | 19.21 |
| 85% | 1075 | 19.28 |
| 90% | 1085 | 19.43 |
| 95% | 1105 | 19.64 |
| 100% | 1160 | 20.00 |
MFR-NODE
The Multifunction Research Node has been designed to provide flexible communication, sensor and power options.
The MFR-NODE supports SDI-12 and 4 x dry contact digital inputs as well as 2x differential / 4x single ended analogue inputs. The MFR-NODE supports sensors with higher power requirements; a solar panel can charge either the internal lithium-ion battery or both the node and sensor can be powered by an external 12V system (e.g. battery or mains source). Optional CAT-M1 provides an option for remote installation in areas outside the range of existing LoRaWAN networks. The optional multiconstellation GNSS ensures you won’t lose track of your device. The MFR-NODE has an onboard 8GB SD Card to provide data logging capabilities and full data redundancy in the event of temporary loss of communications or dropped packets – ideal for research applications.
- LoRaWAN™ low-power long-range connectivity
- 8GB SD Card for data storage
- Supporting SDI-12, 2 x 32-bit dry-contact counting digital inputs.
- 24-bit ADC for 2x differential / 4x single ended sensor.
- Optional CAT-M1
- Solar rechargeable Lithium-ion or external 12V power options
- Optional Multi-constellation GNSS
- External solar/battery input: 12-32V DC.
MP306 Moisture Sensor
Measure volumetric soil moisture for scientific research, agriculture and civil engineering.
The MP306 has a compact body and the needles are arranged in a single plane making it ideal for use in soil columns. It is also ideally suited to measuring pots in glasshouses and growth cabinets. The MP306 can also be installed in the field, with a lifespan of 20+ years in the most extreme conditions.
- 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
Measurement |
|
| Measurement Range | 0-100 VSW% |
| Accuracy | 1% VSW% after calibration to a specific soil type ± 5 VSW% using the supplied soil calibration |
| Resolution | 0.01% VSW% |
| Response Time | Less than 0.5 seconds |
| Stabilisation Time | 3 seconds approximately from power-up |
Interface |
|
| Input Requirements | 9-18 V DC unregulated |
| Power Consumption | 14 mA typical, 16mA max |
| Output signal | 0-1160mV for 0-100 VSW% |
Mechanical |
|
| Total Length | 199 mm |
| Needle Length | 60 mm |
| Needle Seperation | 8 mm |
| Needles | Stainless Steel (Grade 316) – does not corrode in saline solutions |
| Exterior | ABS Plastic |
| Cable | 4.5m Standard |
Other |
|
| Environment | Designed for permanent or temporary burial |
