NBL-S-TMSMS Multi-Depth Soil Moisture & Temperature Sensor

The NiuBoL NBL-S-TMSMS is a tubular multi-depth soil moisture and temperature sensor designed to monitor water and temperature conditions at multiple soil layers from one installation point.

The sensor uses FDR (Frequency Domain Reflectometry) technology for soil moisture measurement and digital temperature sensing for each configured soil layer. Standard monitoring depths include 10 cm, 20 cm, 30 cm and 40 cm, while additional monitoring layers can be customized according to crop root depth and project requirements.

Multi-depth monitoring provides a vertical soil-moisture profile rather than a single-point reading. This is particularly useful for irrigation management, orchards, deep-rooted crops, greenhouse cultivation, soil research and agricultural IoT systems.

The sensor supports RS485 Modbus RTU communication and can be integrated with data loggers, irrigation controllers, PLCs and IoT gateways. Solar power, battery supply and remote 4G communication can also be configured for unattended field monitoring.

NBL-S-TMSMS Multi-Depth Soil Moisture & Temperature Sensor Technical Specifications

What Is a Multi-Depth Soil Moisture Sensor?

A conventional soil moisture probe normally measures conditions around one installation depth. A multi-depth soil moisture sensor measures several layers along the same vertical soil profile.

For example, a 4-layer NBL-S-TMSMS configuration can monitor:

Additional depths can be customized for deeper root systems, orchards, forestry, research plots and other applications requiring a deeper soil profile.

Why Measure Soil Moisture at Multiple Depths?

Water does not move uniformly through the soil profile. Rainfall, irrigation, evaporation, root uptake, drainage and soil texture can create very different moisture conditions at different depths.

Multi-depth monitoring helps distinguish between conditions such as:

• Wet topsoil with a dry deeper root zone

• Dry surface soil with adequate moisture deeper in the profile

• Water moving downward after irrigation

• Excessive irrigation reaching below the active root zone

• Slow drainage after heavy rainfall

• Different water-use patterns through the crop root profile

This vertical information can provide a more useful basis for irrigation management than one single-depth measurement.

Soil Moisture Profile Example

The interpretation depends on crop type, rooting depth, soil texture and irrigation strategy. The example illustrates how multiple depths can reveal water movement that a single probe cannot show.

How Does the Multi-Depth Soil Moisture Sensor Work?

The NBL-S-TMSMS uses FDR (Frequency Domain Reflectometry) technology at multiple sensing positions along the tubular probe.

Each soil-moisture sensing section detects the dielectric response of the soil surrounding that specific depth. Water has a substantially different dielectric constant from dry soil and air, so changes in volumetric water content produce measurable changes in the sensor response.

Digital temperature sensing elements provide corresponding soil-temperature measurements at the configured monitoring layers.

All layer measurements are collected through one tubular probe and transmitted through the same RS485 communication interface.

Multi-Depth Sensor Structure

The tubular structure positions several sensing nodes vertically through the soil profile while minimizing the number of separate cables and surface connections required.

The standard tube diameter is approximately Φ63 mm. Overall probe length varies according to the number and depth of monitoring layers.

Standard and Customized Monitoring Depths

Standard monitoring nodes are commonly configured at:

10 cm → 20 cm → 30 cm → 40 cm

Additional monitoring depths can be customized for applications that require deeper measurements. The product platform supports configurations with up to approximately 10 monitoring layers.

The correct depths should be selected according to:

• Crop rooting depth

• Soil profile

• Irrigation method

• Expected wetting depth

• Drainage characteristics

• Research objectives

Multi-Depth Soil Sensor for Irrigation

Multi-layer soil moisture monitoring is particularly useful for irrigation because it shows both the amount of water present and how deeply irrigation water has moved.

For example:

Irrigation → 10 cm Moisture Rises → 20 cm Rises → 30 cm Rises → 40 cm Remains Stable

This pattern can indicate that irrigation has wetted the main root zone without excessive deep percolation.

If all deeper layers continue to increase after irrigation, water may be moving below the intended root zone. If only the shallow layer changes, irrigation may not be reaching deeper roots.

Actual irrigation decisions should consider crop requirements, soil texture, root depth and local agronomic conditions.

Applications for Different Crop Types

Field Installation Examples

The tubular sensor is installed vertically so that each internal sensing node corresponds to its intended soil depth.

How to Install the Multi-Depth Soil Moisture Sensor

1. Select a Representative Location

Choose a monitoring position that represents the crop, soil type, irrigation zone and terrain being monitored. Avoid unusually wet depressions, drainage channels and locations that do not represent the surrounding field.

2. Drill a Vertical Installation Hole

Use a suitable soil auger to create a vertical hole. The hole should follow the intended sensor axis and should not be significantly wider than necessary.

3. Prepare the Required Depth

The installation hole should extend slightly below the final sensor depth so the probe can be positioned correctly without excessive force.

4. Ensure Close Soil Contact

Good contact between the outside of the tube and surrounding soil is essential for reliable FDR measurement. Suitable soil slurry or backfilling can be used during installation to reduce air gaps around the sensor.

5. Align the Sensor with the Ground Surface

The sensor reference point should be aligned with the soil surface so the internal sensing layers correspond to their intended monitoring depths.

6. Do Not Hammer the Sensor

The tubular probe should not be driven into the ground with heavy impact. If resistance is encountered, enlarge or correct the installation hole before inserting the sensor.

Why Installation Contact Matters

FDR measurements respond to the dielectric properties of the soil surrounding the tube. Air gaps between the probe and soil have very different dielectric properties and can therefore affect the measured value.

Installation should aim for uniform soil contact around the full sensing section, particularly at each monitoring layer.

RS485 Modbus Communication

The NBL-S-TMSMS provides RS485 Modbus RTU output for integration with agricultural controllers and monitoring systems.

Multi-Layer Modbus Data Structure

The sensor transmits moisture and temperature data for each configured monitoring layer. A typical multi-layer data sequence can include:

The exact number of returned channels depends on the number of monitoring layers configured for the sensor.

RS485 Wiring

Installation note: Connection should follow the cable identification supplied with the sensor, particularly for customized configurations.

Solar-Powered Multi-Depth Soil Monitoring

Remote agricultural sites can use a solar-powered configuration when mains electricity is unavailable.

A typical remote configuration includes:

Multi-Depth Soil Sensor → Data Logger / 4G Gateway → Solar Panel + Battery → Cloud or Private Server

Solar-panel and battery capacity should be selected according to the sensor, data logger, communication equipment, reporting interval and local solar conditions.

4G Remote Soil Moisture Monitoring

For unattended monitoring sites, soil moisture and temperature data can be transmitted remotely through a compatible 4G data logger or gateway.

10 / 20 / 30 / 40 cm Soil Data → RS485 → 4G Gateway → MQTT / HTTP → Cloud or Private Server

This architecture allows users to review soil-water profiles without visiting each field monitoring location manually.

Optional GPS, Tilt and Vibration Monitoring

Special configurations can integrate additional monitoring functions such as GPS positioning, inclination measurement and vibration alarms for projects requiring equipment-position or ground-movement information.

These options are mainly intended for specialized monitoring applications and are not required for standard agricultural soil-moisture measurement.

Multi-Depth Sensor vs Separate Soil Moisture Probes

A tubular multi-depth sensor is particularly suitable where a consistent vertical soil profile is required. Separate probes may be more suitable when sensors must be positioned independently at different horizontal locations.

Factors That Affect Multi-Depth Soil Moisture Measurements

Applications of the NBL-S-TMSMS Multi-Depth Soil Moisture & Temperature Sensor

• Water-saving irrigation

• Precision agriculture

• Fruit orchards

• Vineyards

• Greenhouse cultivation

• Vegetable production

• Flower and horticultural production

• Grassland and pasture monitoring

• Forestry

• Soil-water research

• Environmental monitoring

• Agricultural IoT systems

How to Select Monitoring Depths

Monitoring depths should reflect the crop root system and irrigation-management objective.

For product selection, consider:

• Maximum active root depth

• Main root-density zone

• Irrigation wetting depth

• Soil horizon structure

• Drainage depth

• Required number of monitoring layers

• Research or experimental requirements

For example, a shallow-rooted crop may require monitoring mainly within the upper soil profile, while orchards and perennial crops may benefit from deeper monitoring layers.

Common Installation Mistakes

• Installing the sensor in an unrepresentative low or wet area

• Creating an oversized borehole that leaves air gaps around the tube

• Failing to align the sensor reference point with the soil surface

• Hammering the sensor into hard soil

• Using incorrect monitoring depths for the crop root zone

• Installing too close to a drainage ditch or water channel

• Failing to document the configured depths and Modbus address

• Moving the monitoring location frequently, reducing long-term data comparability

Multi-Depth Soil Moisture Sensor FAQ

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

A1. It measures soil moisture and soil temperature at multiple depths along one vertical soil profile.

Q2. What are the standard monitoring depths?

A2. Standard monitoring layers are commonly configured at 10 cm, 20 cm, 30 cm and 40 cm.

Q3. Can monitoring depths be customized?

A3. Yes. Additional monitoring depths can be configured according to root depth and project requirements, with multi-layer configurations available up to approximately 10 monitoring nodes.

Q4. What technology is used to measure soil moisture?

A4. The NBL-S-TMSMS uses FDR (Frequency Domain Reflectometry) technology.

Q5. Does every layer measure both moisture and temperature?

A5. The standard configuration provides soil moisture and temperature measurements for the configured soil layers.

Q6. What is the soil moisture accuracy?

A6. The specified laboratory soil-moisture accuracy is ±3%. Field performance is also influenced by installation quality, soil contact and local soil conditions.

Q7. Does the sensor support RS485 Modbus?

A7. Yes. The sensor supports RS485 Modbus RTU with a configurable device address.

Q8. Can the sensor use solar power?

A8. Yes. A remote monitoring configuration can use solar power and battery storage when mains electricity is unavailable.

Q9. Can soil data be transmitted through 4G?

A9. Yes. The RS485 sensor can connect to a compatible 4G data logger or gateway for remote transmission.

Q10. Can data be sent to a private server?

A10. Yes. A compatible gateway can transmit the soil data to a private server through MQTT, HTTP or TCP depending on the selected system.

Q11. Is a multi-depth sensor better than several separate probes?

A11. The tubular sensor is well suited to continuous vertical-profile monitoring from one location. Separate probes provide greater flexibility when each depth must be positioned independently.

Q12. How should the monitoring location be selected?

A12. Select a representative area based on crop type, soil type, terrain and irrigation conditions, while avoiding unusual low points, water channels and locations affected by lateral seepage.

NBL-S-TMSMS Multi-Depth Soil Moisture & Temperature Sensor Datasheet

NBL-S-TMSMS-Tubular-Multi-depth-Soil-Moisture-Sensor-Instruction-Manual.pdf

Request an NBL-S-TMSMS Quotation

The NBL-S-TMSMS can be configured according to required monitoring depths and the number of soil layers. It can operate as a local RS485 sensor or as part of a solar-powered remote agricultural monitoring system.

For system selection, specify the required monitoring depths, number of layers, quantity of monitoring points, communication method, available power supply and whether remote 4G or private-server integration is required.

View NBL-S-TMSMS Multi-Depth Soil Moisture & Temperature Sensor →