IoT Soil Water Potential
Jetfill Tensiometers for Irrigation Scheduling
Jetfill tensiometers can measure very accurately small changes in soil water potential in the range 0-70 kPa, turf and vegetable crops are typically irrigated at 30kPa and cereal crops closer to 50kPa. The basic components of a tensiometer include a porous ceramic cup, a plastic body tube, water reservoir, and a vacuum transducer. The ceramic cup is placed in good hydraulic contact with the soil and allows transfer of water into and out of the tensiometer body according to the tension in the soil. The vacuum inside the tensiometer body equilibrates with the soil water tension, and there is direct response with a vacuum transducer.
The jetfill tensiometers are available in a range of lengths to suit the required measurement depth in the range of 15 – 150cm, see product link for details on available models.
The MFR-NODE (LoRaWAN or CATM1/NB-IoT) supports up to 4 x Jetfill tensiometers
TM7 Tensiomark for Soil Matric Potential
The TM7 Tensiomark is a fast response soil matric potential sensor which measures soil water tension from pF 0 up to pF 7 (1 up to 1,000,000 kPa). Plant wilting point is 1,500kPa, Maintenance free and frost resistant, the TM7 Tensiomark is factory calibrated and has excellent accuracy and stability.
The MFR-NODE (LoRaWAN or CATM1/NB-IoT) supports up to 2 x TM7 Tensiomark
The S-NODE (LoRaWAN or CATM1/NB-IoT) supports up to 2 x TM7 Tensiomark
The JetFill Tensiometer is available in the following sizes:
- 2725ARL06 JET FILL TENSIOMETER, 6 inch length, .76 Lbs (.34kgs)
- 2725ARL12 JET FILL TENSIOMETER, 12 inch length, .90 Lbs (.41kgs)
- 2725ARL18 JET FILL TENSIOMETER, 18 inch length, 1.03 Lbs (.47kgs)
- 2725ARL24 JET FILL TENSIOMETER, 24 inch length, 1.15 Lbs (.52kgs)
- 2725ARL36 JET FILL TENSIOMETER, 36 inch length, 1.42 Lbs (.64kgs)
- 2725ARL48 JET FILL TENSIOMETER, 48 inch length, 1.68 Lbs (.76kgs)
- 2725ARL60 JET FILL TENSIOMETER, 60 inch length, 1.94 Lbs (.88kgs)
Combined with a GT3 pressure transducer, the tensiometer can be integrated with the MFR-Node or S-Node to become an IoT enabled soil water potential system.
| Range: | +100kPa to -100kPa |
| Signal: | Ratio Metric to its supply voltage. Differential Output.
At input 10.0 V output signal is: -100 kPa = -100 +/- 3 mV and 0 kPa = 0 +/- 3 mV |
| Temperature shift: | Temperature compensated in the range 0–50°C. Typical shift 0.5% full scale. |
| Voltage output: | Transducer has a 4 wire output signal. |
| Resolution: | 0.1 kPa |
| Accuracy: | ±1.0% span |
| Power Requirements | |
| Power Supply: | 10.0 V DC typical, 16.0 V maximum stabilised |
| Current consumption: | 1.3 mA @ 10.0 V |
Tensiomark
| Measuring principle | Heat Capacity |
| Ranges | pF 0~pF 7,0 ≙ 1~10.000.000 hPa
-40~+80 °C |
| Resolution | 0.01 pF, 0,1 °C |
| Accuracy | ca. +/- 30 hPa & 5 % FS = 0,35 pF Note: In general, best results will be produced with sensing cycles of 15 minutes because 15 minutes cycles are used in the calibration process |
| Shortest Sensing Cycle | 15 min |
| Waiting time | 15-20 sec (Duty cycle of the data logger before measurement) |
| Output signal | SDI-12, optional analogue |
| SDI-12-Signal | pF-Wert 0~7, Temp. in °C |
| Analogue signal | -40°~60°C
Sensors can be used at higher temperatures under some conditions. Contact us for more details. Water potential measurements will not be accurate below 0°C. |
| Power supply | 7~14 V DC (12 V recommended) |
| Dimensions | |
| Length | 125 mm |
| Diameter | 20 mm |
| Cable | Standard length: 5 m. Min. bending radius: 90 mm |
| Sheath | PUR, UV-resistant, temperature range –30~+95 °C |
| Sensor Body | Stainless steel |
| Sensor Head | Ceramic |
