Multifunctional low-power soil probe for greenhouse gas emissions monitoring

Overview

This solution is a low-cost, battery-powered wireless probe designed for continuous monitoring of soil greenhouse gas (GHG) emissions, including carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). Built upon a field-validated CO2 probe platform, the new version incorporates an exchangeable sensor cap that enables flexible measurement of multiple GHG species using a single hardware form factor. The probe is designed for extended field deployment in agricultural and environmental settings, providing researchers and land managers with accessible, scalable tools for soil carbon and GHG flux monitoring.

Technical specifications

Key features:

• Exchangeable sensor module allows the same probe body to measure CO2, N2O, or CH4 by swapping the inner circuit boards and sensor cap
• Multi-parameter sensing including greenhouse gas concentrations, volatile organic compounds (VOCs), soil temperature, and humidity
• Low-power operation with a 2-minute sample rate enabling more than 14 days of continuous deployment on a single battery charge
• Wireless data transmission via LoRa (long-range, low-power) connectivity for remote access without on-site infrastructure
• Depth profiling capability validated at 3, 5, and 15 cm soil depths, enabling soil flux derivation using the gradient method
• Compact form factor suited to high-density spatial sampling, with a target deployment density of 6 sensors per 100 acres across 3 soil types
• Per-unit cost under $1,000, significantly lower than many commercial alternatives

Technology readiness level

The CO2 version of the probe has been field validated across three deployments at Warwick Crop Centre during summer and autumn, including a 14-day September 2022 trial with 9 probes at three locations and three depths. Results showed consistent diurnal and depth variation in CO2 concentrations, agreeing with data from a commercial Vaisala GMP343 reference sensor. The current CO2 design is in journal review. The N2O and CH4 sensor modules are in the adaptation phase, with field validation planned at the Wellesbourne agricultural research facility in the UK. The technology is at an advanced prototype stage with demonstrated field performance for CO2 and near-term readiness for multi-gas deployment following ongoing validation.