Innovative Fraunhofer System Uses Photoacoustic Technology to Support Sustainable and Climate-Aware Farming Practices

© Fraunhofer IPM
Field test: Fraunhofer researchers use N2O flux chambers and a special portable system to measure nitrous oxide emitted from the soil in a field.

(IN BRIEF) Fraunhofer IPM has developed a portable and cost-effective system to measure nitrous oxide emissions directly in agricultural fields, helping farmers optimize fertilization and reduce environmental impact. Nitrous oxide, a major greenhouse gas produced by excess nitrogen in soil, has traditionally been difficult to measure due to complex and expensive laboratory processes. The new device uses resonant photoacoustic technology to detect gas concentrations in real time, converting light absorption into sound signals captured by a compact sensor system. Field tests demonstrate its ability to analyze emissions efficiently under varying environmental conditions, supported by integrated humidity control for accurate readings. The system enables direct comparison of fertilization methods, such as conventional and depot fertilization, which can reduce emissions and improve yields. It can also be adapted to monitor other gases like ammonia and carbon dioxide, making it a versatile solution for sustainable agriculture and climate-focused farming strategies.

(PRESS RELEASE) MUNICH, 4-May-2026 — /EuropaWire/ — Researchers at the Fraunhofer Institute for Physical Measurement Techniques have introduced a new compact measurement system designed to detect nitrous oxide emissions directly in farmland, offering a practical tool to improve fertilization efficiency and reduce environmental impact. The innovation addresses a critical challenge in agriculture, as nitrous oxide (N₂O) is the third most impactful greenhouse gas after carbon dioxide and methane and is largely generated through nitrogen fertilization.

Rising fertilizer costs and increasing environmental concerns have intensified the need for more precise fertilization strategies. Excess nitrogen not only leads to groundwater contamination through nitrate accumulation but is also converted by soil microorganisms into nitrous oxide, which is released into the atmosphere. Monitoring these emissions has traditionally been difficult, requiring costly and time-consuming laboratory analysis.

The new system, developed במסגרת the ESKILA project, enables direct, real-time measurement of nitrous oxide emissions in the field. According to Gerrit Stiefvater, the portable device allows researchers and farmers to better understand how soils respond to fertilization and to optimize the quantity of nutrients applied.

During field trials, researchers used flux chambers placed across farmland to collect gas emissions from the soil. The captured gas is then transferred into a lightweight, suitcase-sized measurement unit weighing approximately 5.5 kilograms, where it is analyzed on-site.

The system relies on resonant photoacoustic measurement technology, which detects gas concentrations by converting light absorption into sound signals. Unlike traditional optical methods, this approach measures the acoustic waves generated when gas molecules respond to modulated laser light. Raimund Brunner explained that the measurement cell acts as a resonator, amplifying these signals and enabling highly sensitive detection using a compact design. A MEMS microphone, similar to those used in smartphones, captures the sound, allowing the system to determine gas concentration based on signal intensity.

To ensure reliable results under varying environmental conditions, the system incorporates a humidity control mechanism. This feature stabilizes moisture levels in the measurement chamber, preventing fluctuations that could otherwise affect accuracy.

The technology provides a new way to evaluate different fertilization approaches directly in the field. In particular, it supports comparisons between conventional broadcast fertilization and more targeted methods such as depot fertilization, where nutrients are placed deeper in the soil. This method has been shown to reduce nitrous oxide emissions while improving crop yields.

Beyond nitrous oxide, the system can also be adapted to measure other gases relevant to agriculture, including ammonia and carbon dioxide. This flexibility positions the technology as a valuable tool for advancing climate-conscious farming practices and supporting more sustainable agricultural systems.

Media Contact:

Holger Kock
Head of Communications and Media
Fraunhofer Institute for Physical Measurement Techniques IPM
Georges-Köhler-Allee 301
79110 Freiburg, Germany
Phone: +49 761 8857-129
Fax: +49 761 8857-224
email: Holger.Kock@ipm.fraunhofer.de

SOURCE: Fraunhofer-Gesellschaft