TDR Soil Moisture Sensor

The Acclima True TDR Soil Moisture Sensor Kit delivers industry leading precision and reliability in measuring volumetric water content (VWC) in soils and porous media — using fully integrated Time Domain Reflectometry (TDR) technology. Designed for both field and research applications, this sensor kit offers ultra fast waveform generation and digitisation, minimal influence from soil electrical conductivity or compaction, and seamless data integration via SDI 12 protocol. With rugged housing and a “plug and read” design, it’s ideal for environmental monitoring, agriculture, precision irrigation, geotechnical investigations and long term installations.

KEY Feature /Highlights

• • True TDR technology with waveform digitising resolution down to ~5 ps — delivers high accuracy VWC reading.
• • Wide measurement range: Volumetric Water Content from 0 % to 100 %.
• • Measures additional parameters: Bulk soil electrical conductivity (Bulk EC) and soil temperature — depending on model.
• • Ultra low power consumption (especially H series models) for long term deployments.
• • SDI 12 digital interface (standardised) ensures compatibility with many dataloggers and telemetry systems.
• • Flexible installation options: vertical (in augered hole) or horizontal (in trench) depending on model.

Technical Specification

Application

• • Precision irrigation and water management in agriculture and horticulture: monitoring soil moisture profiles to optimise watering schedules.
• • Environmental monitoring & research: long term soil moisture tracking for watershed studies, climate research, unsaturated zone investigations.
• • Geotechnical & construction: soil moisture condition monitoring for stability, compaction and foundation works.
• • Greenhouse / substrate and soilless media monitoring (models with shorter rods) for horticulture and controlled cultivation.
• • Irrigation infrastructure & smart farming: integration into telemetry/logging systems for automated control and optimisation.

Benifits / User Advantages

• • Provides highly accurate, laboratory grade volumetric water content readings — superior to many older capacitance/impedance sensors.
• • Digital output (SDI 12) and rugged build make it ideal for integration into pro systems and remote monitoring setups.
• • Minimal calibration drift and reduced sensitivity to soil salinity and compaction, simplifying long term reliability.
• • The modular rod options and installation flexibility allow users to adapt to different soil depths, substrates or site conditions.
• • Low power models enable long term deployment in remote/field sites with minimal maintenance.

Best Practice & Consideration

• • While the sensor’s accuracy is high, very extreme soils (very high clay, frozen ground, extremely saline) may require site specific calibration or selection of specific model (like high EC version).
• • Use compatible dataloggers and ensure proper SDI 12 wiring/termination for reliable readings and data capture.
• • Keep cable connectors sealed and housing intact (epoxy sealed) to maintain durability and avoid moisture ingress.
• • In mixed media/substrate (e.g., soilless mix, rockwool) look at models tailored for such (e.g., TDR 310W) for optimal performance.