Soil Moisture - TDR Systems

Soil Moisture (TDR)

TDR (Time Domain Reflectrometry) allows very accurate determination of soil moisture content. This technology is very specialised and Van Walt is proud to represent the new Blue-Edition range of soil moisture meters from the very progressive manufacturer: IMKO.

A NEW RANGE OF PRECISION TDR MOISTURE AND TEMPERATURE MEASUREMENT METERS AT A PRICE EQUIVALENT TO A GOOD QUALITY CAPACITANCE PROBE.

PICO-BT Bluetooth Module

The Pico BT Bluetooth Module TDR system has excellent characteristics:

• Very small portable device, not much larger than a calculator.
• Immediate soil moisture reading as percent by volume.
• Simultaneous TDR level can correlate with soil conductivity.
• Rechargeable batteries allow up to 300 measurements on one charge.
• Different probe lengths available.
• Can be used with tube probe as possible replacement for neutron probe.
• TRIME probes can be networked for automated measurements.
• Measures a much wider volume than other meters.
• Much more accurate than capacitance probes.

This system enables fast measurements at different points with different probes. The PICO-BT Bluetooth Module detects the serial number and sensor type and stores the information on your PDA.

Just one PDA and one Pico-BT are necessary to read any quantity of sensors.

Because the Pico is a TDR device it is more powerful and accurate than devices based on capacitance/frequency domain electronics.
For extremely accurate soil moisture measurements you will require:

A Trime Pico 64 "Intelligent" field installation moisture sensor version P2 with integrated TDR electronics and temperature sensor (integrated in the probe base). IP 68 sealed, Probe-ø: 64mm, Rod length: 160mm, Rod-ø: 6,0mm. Measurement influence approximately 1.25 litres and 1.5 metres of cable.

Each additional measuring point requires just one Pico-64 sensor.

You will also need, just one handheld unit to capture and store soil moisture data from any number of sensors. The Pico Bluetooth module PICO-BT takes care of wireless transfer of soil moisture and soil temperature data to a PDA, Windows Mobile device with PICO TALK software.

To access your data any handheld PDA with integrated Bluetooth with Microsoft® Windows Mobile™ 6.0 or 5.0 or Windows® CE can be used. Van Walt can provide a good quality PDA with excellent ruggedised case to cope with the rigours of fieldwork but any PDA of suitable specifications can be used.

TRIME FM2 with probe for top layers

The handy TRIME®-FM displays direct %vol moisture content and TDR level at the touch of a button
Compact and lightweight device for field use with a 2 rod probes.

This sensor is the standard field measuring device for volumetric moisture in porous materials. The broad range of applications in even the most saline materials is without equal.

The intelligent automatic TDR-curve reading electronics are arranged in the robust and waterproof (IP 67) aluminium housing, withstanding even the highest demands of all-day field use.

Its speed and easy push-button operation is unsurpassed. In less than 10 seconds, the water content is shown in % by volume, TDR-level (as a measure of salinity). The data is displayed clearly on a clear 4-line LCD panel.

Engineered to allow maximum flexibility and extension potential, a wide variety of probe types can be connected to the FM-device. A built-in EEPROM in the probe connector case stores all probe parameters such as type and cable length and soil specific calibration data.

TRIME FM3 with tube probe

With similar attributes to the TRIME FM2 the FM3 can utilise a tube probe which is used for soil moisture profiling within access tubes positioned in soil up to 3 metres depth.  A very credible replacement for the now defunct neutron probe.