4-in-1 Soil Temperature Moisture EC Salinity Sensor

The NiuBoL NBL-S-TMCS is a 4-in-1 soil sensor that measures soil temperature, moisture, electrical conductivity (EC) and salinity from one probe. It is designed for agricultural irrigation, fertigation, greenhouse cultivation, saline-soil monitoring, soil research and agricultural IoT applications.

The soil moisture channel uses FDR (Frequency Domain Reflectometry) technology, while the conductivity channel uses an AC bridge measurement method. Measurement data is transmitted through RS485 Modbus RTU for integration with PLCs, RTUs, data loggers and IoT gateways.

Monitoring temperature, moisture, EC and salinity at the same location provides a more complete view of root-zone water and salt conditions than a single-parameter soil sensor.

NBL-S-TMCS Soil Temperature Moisture EC Salinity Sensor Technical Specifications

Four Soil Parameters in One Probe

The NBL-S-TMCS combines four related soil measurements in one sensing probe, reducing the number of separate sensors, cables and RS485 addresses required at each monitoring point.

Soil Temperature

Soil temperature affects seed germination, root activity, microbial processes and plant development. It also provides useful context when interpreting moisture and conductivity data.

Soil Moisture

Soil moisture indicates the volumetric water condition around the root zone. Continuous moisture monitoring can support irrigation scheduling and help identify whether the soil is becoming too dry or remains excessively wet.

Soil Electrical Conductivity

Electrical conductivity represents the ability of the soil solution to conduct electricity. EC is influenced by soluble ions, fertilizer concentration, irrigation-water quality, soil moisture, temperature and soil characteristics.

Soil Salinity

The salinity channel provides a salt-concentration value in mg/L and can be used to monitor changes in root-zone salt conditions over time.

The salinity value is particularly useful in irrigated agriculture, saline-soil studies, greenhouse cultivation and water-salt monitoring projects.

What Is the Difference Between Soil EC and Salinity?

Soil EC and salinity are closely related because dissolved salts contain ions that conduct electricity. However, the two parameters use different units and describe the measurement in different ways.

Neither EC nor salinity identifies the individual chemical salts present in the soil. Determining specific ions or chemical composition requires an appropriate laboratory or ion-specific analytical method.

What Can Soil EC and Salinity Monitoring Tell You?

Long-term EC and salinity monitoring can help identify changes in the water-salt condition of the root zone.

• Salt accumulation after repeated irrigation

• Changes caused by fertilizer application

• Differences between irrigation zones

• Changes following rainfall or leaching

• Salinity variation between soil depths

• Long-term trends in saline or salt-affected soil

• Changes in greenhouse or cultivation substrates

Appropriate EC and salinity limits vary by crop, soil, substrate, irrigation-water quality and measurement method. Monitoring values should therefore be interpreted together with agronomic requirements rather than using one universal threshold.

How Does FDR Soil Moisture Measurement Work?

The NBL-S-TMCS uses FDR (Frequency Domain Reflectometry) for soil moisture measurement.

The sensor generates an electromagnetic field around the sensing electrodes and measures the dielectric response of the surrounding soil. Water has a substantially different dielectric constant from dry soil and air, so changes in soil water content produce measurable changes in this response.

The sensor electronics process the dielectric response and convert it into a volumetric soil moisture percentage.

How Does Soil EC Measurement Work?

The conductivity channel uses an AC bridge method to measure electrical conductivity between the sensing electrodes.

Dissolved ions in soil water provide the conductive path. As the concentration and mobility of these ions change, the measured electrical conductivity also changes.

The sensor includes built-in conductivity temperature compensation over the 0–50°C range to reduce the influence of temperature on EC measurements.

Why Soil Moisture Affects EC and Salinity Measurement

Soil water provides the medium through which soluble ions conduct electricity. When the soil becomes very dry, the conductive pathways between the electrodes become less continuous and EC measurements may become less representative of the soluble salt condition of the root zone.

When volumetric soil moisture is above approximately 20%, soluble ions generally form a more continuous conductive pathway, allowing conductivity measurements to better reflect soil salt conditions.

The 20% value is a measurement reference rather than a universal irrigation threshold. Soil texture, cultivation substrate, crop type and monitoring objective should also be considered.

For long-term trend analysis, EC and salinity data collected under reasonably similar soil-moisture conditions provide better comparability.

Sensor Structure and Dimensions

The NBL-S-TMCS uses three corrosion-resistant sensing electrodes and a sealed epoxy-resin housing for direct insertion into soil or other suitable measured media.

For soil measurement, all three electrodes should be inserted fully into the soil so the sensing area remains in close contact with the measured medium.

RS485 Modbus Communication

The NBL-S-TMCS uses RS485 Modbus RTU for integration with compatible data loggers, PLCs, RTUs and agricultural IoT gateways.

RS485 Wiring

Installation note: Wiring should follow the identification supplied with the sensor, particularly when customized cables or connectors are used.

How to Install the 4-in-1 Soil Sensor

Quick Field Measurement

Select a representative measurement location and avoid stones, large roots and other hard objects.

Insert the three electrodes fully into the soil and maintain close contact with the surrounding soil. Avoid rocking the sensor from side to side because this can create air gaps around the sensing electrodes.

For field surveys, several measurements within the same representative zone can provide a more useful indication than a single isolated reading.

Long-Term Buried Installation

For continuous monitoring, dig to the required measurement depth and insert the sensing electrodes horizontally into an undisturbed soil wall.

Backfill and compact the soil carefully so the electrodes remain in close contact with the surrounding soil.

For hard soil, prepare an appropriate pilot hole before inserting the probe. Strong impact or hammering should be avoided.

4-in-1 Soil Sensor for Irrigation and Fertigation

The NBL-S-TMCS is suitable for irrigation and fertigation systems where both soil water conditions and salt accumulation need to be monitored.

NBL-S-TMCS → RS485 → Irrigation Controller / Data Logger → 4G / Ethernet → Cloud or Private Server

Monitoring Saline and Salt-Affected Soil

The NBL-S-TMCS is suitable for long-term monitoring of water-salt dynamics in saline or salt-affected soil.

Multi-point or multi-depth monitoring can help evaluate:

• Salt accumulation in the root zone

• Changes after irrigation

• Changes following rainfall

• Effectiveness of leaching

• Salt movement between soil layers

• Differences between irrigation zones

• Seasonal water-salt changes

For projects requiring several measurement depths, individual sensors can be installed at multiple depths or a suitable multi-depth soil monitoring sensor can be selected.

Nutrient Solution and Substrate Monitoring

The conductivity measurement can also be used with suitable water-fertilizer solutions, nutrient solutions and cultivation substrates within the specified measurement range.

For liquid or substrate monitoring, the expected EC range, installation method, cleaning requirements and long-term material compatibility should be considered when configuring the system.

Multiple Sensors on One RS485 Network

Multiple NBL-S-TMCS sensors can share one RS485 Modbus network when each device uses a unique address.

• Assign a unique Modbus address to each sensor.

• Use twisted-pair cable for RS485 communication.

• Prefer daisy-chain wiring where practical.

• Use a suitable DC power supply.

• Calculate voltage drop on long power cables.

• Use RS485 termination where required.

• Record the sensor address, installation location and measurement depth.

Field A → Zone 03 → Depth 30 cm → Modbus Address 07

Factors That Affect EC and Salinity Readings

Applications of the NBL-S-TMCS

• Smart irrigation

• Fertigation monitoring

• Saline-soil monitoring

• Greenhouse cultivation

• Precision agriculture

• Vegetable production

• Fruit orchards

• Grassland and pasture monitoring

• Soil water-salt research

• Land reclamation

• Plant cultivation

• Agricultural IoT systems

NBL-S-TMCS vs Other Soil Sensors

Common Measurement and Installation Errors

• Using %RH to describe soil moisture instead of volumetric moisture percentage

• Interpreting EC as a direct measurement of individual nutrients

• Interpreting salinity as identification of specific salt compounds

• Comparing EC readings taken under very different moisture conditions

• Ignoring the salinity of irrigation water

• Leaving air gaps around the sensing electrodes

• Using one monitoring point to represent a highly variable field

• Ignoring soil depth when evaluating salt accumulation

• Using duplicate Modbus addresses on the same RS485 bus

4-in-1 Soil Temperature Moisture EC Salinity Sensor FAQ

Q1. What does the NBL-S-TMCS measure?

A1. It simultaneously measures soil temperature, moisture, electrical conductivity and salinity.

Q2. What is the soil moisture measurement range?

A2. The soil moisture range is 0–100% with 0.1% resolution.

Q3. What is the EC measurement range?

A3. The EC range is 0–10000 μS/cm with 1 μS/cm resolution.

Q4. What is the soil salinity measurement range?

A4. The salinity range is 0–8000 mg/L with 1 mg/L resolution.

Q5. What technology is used to measure soil moisture?

A5. The NBL-S-TMCS uses FDR (Frequency Domain Reflectometry) technology for soil moisture measurement.

Q6. What method is used for EC measurement?

A6. The conductivity channel uses an AC bridge measurement method with built-in temperature compensation.

Q7. Are soil EC and salinity the same?

A7. No. They are related parameters but use different units. EC is reported in μS/cm, while the salinity channel is reported in mg/L.

Q8. Does the sensor identify individual salts or nutrients?

A8. No. EC and salinity describe overall conductivity and salt conditions. Individual ions or nutrients require appropriate chemical or laboratory analysis.

Q9. Can the sensor remain buried for long-term monitoring?

A9. Yes. The IP68 probe is suitable for long-term monitoring when installed correctly with good contact between the sensing electrodes and the measured soil or substrate.

Q10. Can several NBL-S-TMCS sensors share one RS485 bus?

A10. Yes. Each sensor must use a unique Modbus address, and the RS485 wiring and power supply should be designed correctly.

Q11. Can the sensor be used in nutrient solutions?

A11. The conductivity measurement can be used with suitable water-fertilizer solutions, nutrient solutions and substrates when the expected values remain within the specified measurement range.

Q12. Can the data be transmitted to a private server?

A12. Yes. The RS485 sensor can connect to a compatible data logger or IoT gateway for MQTT, HTTP or TCP transmission depending on the system configuration.

NBL-S-TMCS Soil Temperature Moisture EC Salinity Sensor Datasheet

NBL-S-TMCS-Soil-temperature-humidity-salty-EC-sensor.pdf

Request an NBL-S-TMCS Quotation

The NBL-S-TMCS can be used as a single monitoring probe or as part of a multi-point agricultural IoT system. System configuration can be selected according to sensor quantity, cable length, installation depth, communication distance and data-acquisition requirements.

The RS485 sensor can be integrated with PLCs, irrigation controllers, data loggers, LoRaWAN nodes, 4G gateways and private monitoring platforms.

View NBL-S-TMCS 4-in-1 Soil Temperature Moisture EC Salt Sensor →