New IAEA Publication - Use of Laser Carbon Dioxide Carbon Isotope Analysers in Agriculture

Climate-smart agriculture is reorienting agricultural systems to address the intertwined challenges of food security and climate change. An increasing number of scientists are using isotopic techniques to assess the presence of carbon dioxide (CO₂) in the environment and to enhance land management practices in order to reduce emissions from agriculture. The recently published Use of Laser Carbon Dioxide Carbon Isotope Analysers in Agriculture focuses on this specific technique, which helps make agriculture climate smart.

Different agricultural practices have different impact on CO₂ release or capture – affecting CO₂ concentrations in the air. Ploughing, for example, can stimulate the decomposition of organic matter in the soil, leading to the release of more CO₂, while the use of mulch could help soil and microbes store CO₂, said Maria Heiling, senior laboratory technician at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. “Countries around the world are trying to produce no more greenhouse gases than necessary, and the laser carbon dioxide isotope analyser is a tool to help in CO₂ emission assessment to improve a country’s agricultural management practices.”

Compared to conventional methods, the laser CO₂ carbon isotope analyser is more robust and can provide continuous real-time measurements of CO₂ concentration emitted by the soil. To provide reliable data, the analyser must be used with care: “Although laser isotope analysers are easier to operate than conventional analytic equipment, the results could easily be inaccurate if the measurements, instrument calibration and data management are not done properly,” Heiling explained. This publication contains specific protocols to ensure the accuracy of measurements, with particular focus on calibration and data handling.

As more scientists, technicians and students turn to laser isotope analysers as an alternative to conventional methods, such as gas chromatography and isotope ratio mass spectroscopy, to track the amount and isotopic signature of CO₂ in the atmosphere, emitted from soil, microorganisms and plants, there is an increasing demand for guidance on the proper usage of such analysers, Heiling said.

The first section of this publication provides step-by-step procedures with figures and photos on how to create reference gases for isotope analysis, followed by guidance on how to use the analyser in a continuous free-flow mode. The continuous monitoring of CO₂ concentration provides data to understand CO₂ dynamics. “If your analyser produces one CO₂ value per second, and you measure for half an hour, you will end up with a big data set,” Heiling said. To help process and analyse the data, the publication offers concrete guidance on how to import data into table format and to perform specific calculations.