O2-100 Soil Oxygen Sensor

Overview

The O2-100 is Agrinovo’s digital soil oxygen sensor, built to measure the concentration of oxygen in the soil root zone. Oxygen in the soil pore space is a direct indicator of root-zone aeration. Roots, soil microbes, and beneficial fungi all depend on it, and when soil oxygen drops, nutrient uptake slows and root stress follows.

Compaction, overwatering, poor drainage, and saturated conditions all push soil oxygen down, often well before the damage is visible above ground. The O2-100 makes that invisible variable measurable, so growers can diagnose aeration problems, fine-tune irrigation, and confirm that drainage and soil structure are doing their job.

The sensor uses an electrochemical sensing cell with built-in temperature compensation and reports oxygen as a volume percentage (%VOL) over a standard RS485 Modbus RTU interface. It connects to any Agrinovo Genesis controller, the same way every Agrinovo sensor does, so soil oxygen can be logged alongside soil moisture, temperature, and EC on a single modular platform.

Key Features

• Electrochemical oxygen sensing: measures oxygen concentration in soil pore air across a 0-25 %VOL range
• Built-in temperature compensation: stable readings as soil temperature changes through the day and the season
• Fast response: settles in under 15 seconds, so readings keep up with changing conditions
• RS485 Modbus RTU output: standard digital communication for controllers, data loggers, and IoT platforms
• Wide supply range: operates on 7-24V DC, compatible with field and solar power systems
• Configurable Modbus address: run several sensors on a single RS485 bus
• Modular by design: connects to any Agrinovo Genesis controller alongside other sensor types
• Compact probe: 97 mm long, 30 mm diameter, sized for root-zone installation

Applications

• Root-zone aeration monitoring: track oxygen availability where roots actually grow
• Irrigation management: catch the oxygen depletion that follows overwatering and waterlogging
• Drainage and compaction diagnostics: confirm whether soil structure lets air reach the root zone
• Greenhouse and substrate systems: monitor oxygen in coir, rockwool, and other soilless media
• Compost and organic matter: follow oxygen levels through aerobic decomposition
• Soil health and agronomy research: quantify aeration as part of a broader soil monitoring program

Technical Specifications

The O2-100 measures gas-phase oxygen in the soil pore space using an electrochemical sensing cell. A built-in temperature sensor compensates the reading, so accuracy holds across the sensor’s full -20°C to 50°C operating range. Oxygen is reported as a volume percentage (%VOL) across a 0-25 %VOL range, with an accuracy of ±2% of full scale at 25°C and a response time of under 15 seconds.

Because it measures oxygen in soil air rather than dissolved oxygen in water, the O2-100 is best suited to aerated soils and growing media. The sensing membrane should be kept clear of standing water and condensation. In well-drained soil, a reading near 20 %VOL indicates healthy aeration, while a falling reading is an early signal of compaction, saturation, or excessive irrigation.

Connectivity and Integration

The O2-100 communicates over RS485 Modbus RTU, the standard digital protocol used across the Agrinovo sensor range. This makes integration straightforward:

• Agrinovo controllers: pair with the Omni Genesis or the compact Omni Genesis Lite to log and transmit soil oxygen data
• Multi-sensor sites: each sensor has a configurable Modbus address, so a single RS485 bus can carry oxygen, moisture, temperature, and EC sensors together
• Data loggers and IoT platforms: connect through standard Modbus RTU interfaces and RS485 gateways for remote dashboards and alerts

Reading the sensor is simple: a single Modbus holding register returns oxygen concentration, scaled to 0.1 %VOL increments. Full register details and command examples are in the product datasheet.

Installation

Install the probe in the active root zone at the depth you want to monitor, with firm soil contact around the sensing end. For a fuller picture, place sensors at two or three depths to build an oxygen profile through the soil column. Keep the sensing membrane out of standing water, and connect the sensor with correct polarity and within the rated supply voltage, since reverse polarity or overvoltage will damage the sensing cell.

Related Guide: How to Build an IoT Soil Monitoring System