Soil Moisture using TDR technology

TDR (Time Domain Reflectrometry) technology delivers very accurate determination of soil moisture content. The soil moisture content is calculated inside the unit and the collected data can be read from a handheld unit, logged or sent via a telemetry network to a PC for analysis.

This technology is very specialised and Van Walt is proud to represent the new range of soil moisture meters, loggers and telemetry options from IMKO, an award winning German manufacturer.  Precision TDR meters and systems at prices equivalent to good quality capacitance probes.

Soil Moisture readings for top layers

Using a highly accurate TDR probe like the Pico 64 or Pico 32 for:

• Highly accurate TDR technology
• Direct measurement of soil moisture content
• Integrated soil temperature sensor
• Soil electrical conductivity measurements
• Large measurement volumes
• User replaceable rods.
• Trime Pico 32 or Trime Pico 64 probes can be networked, logged or read manually with the HD2 display unit.

How it works

To take measurements the probe rods are inserted into the soil and within a few seconds the moisture measurement and soil EC values and temperature are presented on the HD2 display.

The operating mode "Normal" shows you at a glance the value of Moisture, Temperature, and the RBC (material conductivity).

Manual Soil Profiling Systems

For the accurate measurement of soil profiles the first ever TDR tube access probe - IPH is designed for moisture content profiling:

• Measurements in 160mm  increments to a depth of 3 meters in any number of access tubes
• Special polycarbonate access tubes are installed prior to taking measurements and can be safely left in the soil
• 0...60% volume soil water-content measurement
• Continuous and non-destructive determination of volumetric soil moisture
• Rugged and strong construction for the toughest demands of continuous field use
• Can be connected to an HD2 readout device or a PICO BT Bluetooth system with PDA

How it works

The IPH probe generates a high frequency pulse (up to 1GHz) which propagates along the metal shells, generating an electromagnetic field around the probe. At the end of the shells, the pulse is reflected back to its source. The resulting transit time can be measured and enables the determination of the propagation velocity, which is primarily dependent on the water content. The volumetric water content is then calculated by the velocity and is shown on the display panel immediately.

Automatic Soil Profiling System

The PICO Profile is a new generation of modular profile probes that give precise soil moisture data of selected soil horizons to depths of up to 4 metres. It is normally used with the GlobeLog to create a long term, fixed installation system complete with automatic logging. For additional flexibility and convenience a telemetry system is also available.

• Ideal for the development of soil-water balance models, irrigation control and salt content testing at different soil depths
• Simple modular configuration
• Calibration curves for different soil types
• Connection of data logger via a GPRS wireless modem
• Rugged & waterproof design.

The GlobeLog datalogger:

• Very robust for onsite conditions with protection up to IP67
• Can accept up to 48 channels
• Can be supplied with telemetry option
• Ultra low power
• Connects up to 48 sensors.

Multiple probe/sensor systems

TRIME® system technology is as intelligent as the TDR measurement method so for major environmental, earth sciences, hydrology, forestry and agricultural projects bespoke systems can be developed incorporating modular, flexible, and extendable set-up of TRIME® probes and other sensors (which can be buried in the ground for long term onsite deployment) as part of a network, with simple network administration with software package - GlobeLog control for data recovery and analysis.