Berkeley scientists develop prototype for measuring carbon in soil

photo of plants
Ben Mefford/Staff
The tool, consisting of a neutron generator and gamma and alpha detectors, holds significant potential to combat climate change through carbon dioxide removal.

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Berkeley physicists and soil scientists recently joined efforts to develop a new method for detecting carbon in dirt — without even having to touch soil.

Current methods for measuring carbon in the ground require digging holes to collect and burn soil samples, meaning they are destructive, costly and inefficient, according to Arun Persaud, Lawrence Berkeley National Laboratory, or LBNL, staff scientist and one of the team’s leaders. In contrast, the researchers’ prototype simply scans the ground and offers a 3D measurement of the soil’s distribution of elements.

“Although the instrument is still being developed to work outside the lab, the idea is to use this device, maybe as part of farm machinery to scan the soil as the tractor or harvester moves through the field,” said Eoin Brodie, deputy director of LBNL’s Climate and Ecosystem Sciences Division, in an email.

The tool holds significant potential for combating climate change through carbon dioxide removal. Seeing how soils currently hold three times the amount of carbon than in the atmosphere and four times that of all vegetation, the instrument would allow carbon farmers to better address climate change, according to Brodie.

While markets are attempting to assign dollar values to carbon in soil, current methods make it infeasible to efficiently farm carbon at a large scale, according to Brodie. The tool’s improved method for measuring carbon in soil offers greater efficiency, precision and timeliness.

“It is a very exciting project to work on, since it has direct applications to help fight the climate crisis,” Persaud said in an email. “It would be great to bring this technology to a point where we can show its usefulness and bring it to market.”

The scientists’ efforts to build this prototype started in 2018 with funding from Advanced Research Projects Agency-Energy, according to Persaud. The prototype consists of a neutron generator developed by collaborator Adelphi, Inc. as well as digitizers and gamma and alpha detectors, Persaud added.

The team is starting to test the prototype with the SMART Soils testbed, a device with built-in sensors that allow the researchers to see how plants grow and capture carbon in real time, according to Brodie. After testing the prototype in the testbed’s controlled conditions, the team hopes to test in actual agricultural fields this summer, Persaud added.

“This new carbon sensing method is an example of how accelerator technologies have broad impact, here bringing important sensing to the challenges of climate change and clean industry, bringing together researchers from diverse backgrounds including physical sciences and earth science,” said Cameron Geddes, director of LBNL’s Accelerator Technology and Applied Physics Division, in an email.

Contact Cindy Liu at [email protected], and follow her on Twitter at @_CindyLiu_.