Research Shows the Economic Feasibility of Large-Scale Carbon Measurement for Agricultural GHG Accounting

To incentivize farmers to adopt environmentally beneficial practices, carbon credits are awarded to those who demonstrate practices that draw more carbon into the soil from the atmosphere. However, there is currently a lack of confidence that soil organic carbon credits represent real climate benefits. A research project led by Eric Potash and the Agroecosystem Sustainability Center at the University of Illinois, has shown that a more rigorous approach to soil carbon quantification is possible, one which promises to build confidence in credits representing real climate benefits.

Currently the most common approach to quantifying these soil carbon credits is called “measure-and-model.” In this approach a soil carbon project developer will measure the carbon stocks on their farms before they begin changing the practice, then they will run models on a computer to estimate the change over time.

By contrast, in the “measure-and-remeasure” approach studied by Potash and co-authors, developers measure those carbon stocks before the practice and then go back a few years later to remeasure stocks. This empirical approach can provide more reliable quantification of soil carbon accrual. Yet voluntary carbon markets and other carbon accounting approaches, including national-level greenhouse gas accounting, rely primarily on measure-and-model because of an assumption that the direct measurement approach is too expensive at landscape and regional scales.

Potash along with co-authors Mark Bradford from the Yale School of the Environment, Emily Oldfield from the Environmental Defense Fund, and ASC Director Kaiyu Guan show that measure-and-remeasure can be economically feasible for carbon crediting when a project is scaled up. The team has developed a web app, where developers can plug in a number of variables to determine how much it would cost to implement measure-and-remeasure in their projects and how profitable they can be selling carbon credits.

Instead of using biogeochemical modeling as in the measure-and-model approach, Potash and co-authors use a multilevel statistical model to estimate the costs and benefits of measure-and-remeasure. In this approach, the group estimated how much sampling would need to be done under the more rigorous measure-and-remeasure to precisely quantify the overall effect of climate-smart practices across a large number of fields. Prior academic work on soil carbon measurement hasn’t considered projects on the scale of thousands or tens of thousands of fields that occur in the voluntary carbon market.

Prior to this work, there was a perception of an inherent trade-off between rigor and economic feasibility that led most developers to take up the cheaper but less rigorous measure-and-model. In this research, Potash and co-authors have provided a framework that factors in a host of variables (all the costs and all the benefits), and shows that larger projects can be developed under the measure-and-remeasure approach and still be quite profitable. The web app enables users to interactively explore how these variables affect the economics of their specific SOC projects. Small projects can also use the app to efficiently design soil carbon measurement efforts, though they may not be profitable in the carbon market.

“Ultimately the goal is to incentivise these practices,” Potash said. “There is a huge perceived opportunity to reduce carbon emissions from agriculture and build the health of soils. At the moment, projects are being developed with measure-and-model, but we aren’t confident in their benefits. Before this research, it felt like we didn’t have another option. However, we found that there is a better way forward. Measure-and-remeasure can be economical. We think it will help to build confidence in soil carbon accounting more generally, and not just for carbon markets.”

Primary media contacts: Kaiyu Guan (kaiyug@illinois.edu), Eric Potash (epotash@illinois.edu)

Measure-and-remeasure as an economically feasible approach to crediting soil organic carbon at scale.
E Potash, M Bradford, E Oldfield, and K Guan. Environmental Research Letters. 20 (2025) 024025

Kaiyu Guan, the Founding Director of the Agroecosystem Sustainability Center (ASC) and a professor of Natural Resources and Environmental Sciences at the University of Illinois, has been selected as the American Society of Agronomy (ASA) Plenary E.T. and Vam York Distinguished Lectureship at the ASA annual meeting. The international annual meeting is the largest gathering of soil, crop, and agronomic scientists in the world.

It will be presented at the annual meeting of the ASA, the Crop Science Society of America, and the Soil Science Society of America on Nov. 10-13, 2024, in San Antonio, Texas. This conference is the most important gathering for agricultural scientists in the US and globe, for exchanging and sharing ideas, solutions, and innovation from across the field of agricultural sciences.

Guan will deliver an address titled SYMFONI: The “System-of-Systems” Solution to Quantify Soil Carbon and GHG Outcomes for the U.S. Croplands. Guan is the project leader of SYMFONI, an ARPA-E SMARTFARM project, which advanced the first-of-its-kind system-level quantification of greenhouse emissions for agroecosystems from field to continental scales. His group has developed accurate and scalable quantification of soil carbon and greenhouse gas emissions for corn, soybeans, spring and winter wheat, cotton, rice, pastureland, and miscanthus fields.

Guan founded and directs ASC, which has a mission to revolutionize agricultural systems through research, collaboration, and engagement, bridging science and practice for agricultural productivity and ecosystem sustainability. He is also the Chief Scientist for the NASA Acres Program. His research group uses computational models, satellite data, field work, and artificial intelligence to address how climate and human practices affect crop productivity, water resource availability, and ecosystem functioning. Guan’s group aims to increase our society’s resilience and adaptability to maintain sustainability of ecosystem services, food security and water resources.

The University of Illinois and the Agroecosystem Sustainability Center at Illinois are in the forefront of studying agriculture’s effect on the environment. To that end, ASC hosted “A Symposium on Agricultural Decarbonization” on Wednesday, September 18 on the Illinois campus. 

The event coincided with a 1.5-day visit by Steven Singer, the Program Director at ARPA-E (The Advanced Research Projects Agency-Energy). Singer gave an overview on the program’s vision, which intersects with many of the initiatives spearheaded by ASC. Among those is the SMARTFARM program, which measures N₂O and other greenhouse gas (GHG) emissions. ASC and the Institute for Sustainability, Energy, and Environment was selected as one of the SMARTFARM sites last year.

“I really enjoyed coming to Illinois and hearing about the transformative research occurring in agriculture,” said Singer. “The University of Illinois Urbana-Champaign is a leader in thinking about growing bioenergy crops sustainably, a critical aspect of developing a US bioeconomy.”

ASC Director Kaiyu Guan served as the MC for the event and spoke on “Frontier of agricultural carbon accounting technology.” He pointed to how he and his colleagues have developed a “system of systems” approach and how modeling, cross-scale sensors, and artificial intelligence are instrumental in generating accurate and scalable quantification of GHG and soil carbon change from the field to the national scales.

ASC Associate Director Wendy Yang presented insights on her research on N₂O GHG emission and later moderated a panel featuring many of the speakers. John Reid, newly minted Executive Director of the Center for Digital Agriculture at Illinois, presented remarks on “Circular Bioeconomy.” Andrew Leakey, Director of Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) and Chair Professor of Plant Biology and Crop Sciences, explained how the campus’ biggest research centerCABBI is leading the way in that space. 

“We are thrilled to have Dr. Singer of ARPA-E visit Illinois, and we are thankful for all the support from ARPA-E,” said Guan. “Decarbonizing agricultural production to ensure both high productivity and environmental sustainability is an urgent and essential task that requires huge devotion and efforts. We at Illinois aim to lead this effort and welcome all the collaborations worldwide to join us. We expect this agricultural decarbonization symposium will recur in the coming years and aim to make this as a major event to showcase Illinois’s achievements in this space.”

Through funds from the Inflation Reduction Act (IRA), the Agroecosystem Sustainability Center (ASC) will ramp up efforts to investigate the impact of conservation practices on nitrous oxide and other greenhouse gas (GHG) emissions. The Act, signed into law in 2022, includes a historic investment for implementation of practices that support climate mitigation through the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), in addition to funding to advance estimates of mitigation outcomes.

The Global Change and Photosynthesis Research Unit of the USDA Agricultural Research Service (ARS) is a key collaborator on the work to advance mitigation outcome estimates. The funding will support the ongoing work of ARS plant physiologist and also an adjunct professor at UIUC, Carl Bernacchi and fellow ASC scientists Wendy Yang, Kaiyu Guan, and DoKyoung Lee to advance the understanding of conservation practices on GHG fluxes. Data will be used by modelers to improve mitigation outcome estimates, including estimates for USDA conservation programs and the US national inventory of GHG emissions and sinks.

 “The Inflation Reduction Act provides funding for NRCS to address unmet demand for our conservation programs, and also funding to improve our mitigation outcome estimates and advance national reporting,” said Gayle Barry, the IRA National Coordinator for the USDA Natural Resources Conservation Service. “The work of ARS and partners like the University of Illinois are advancing critical research on the impact of conservation practices on GHG emissions, and we are excited to work together.”

The USDA funding for this project is through fiscal year 2031 and builds on the type of work University of Illinois faculty, the ASC, and Illinois’ Institute for Sustainability, Energy, and Environment is doing through the SMARTFARM Project, supported by the Advanced Research Projects Agency-Energy (ARPA-E). Through the ARS, Bernacchi plans to sign research agreements with ASC scientists or hire researchers within the local ARS to work jointly with those scientists.

“Because of the team that we’ve put together with SMARTFARM, we are ideally situated to expand upon what we have been doing in order to meet the objectives of the section of the IRA funding this work,” Bernacchi said. “Because of the extent of our understanding of greenhouse gas emissions from agriculture as well as modeling, the remote sensing, the infield measurements, and the biogeochemical process modeling and measurements we do, USDA recognized that we are well suited to create an intensive measurement site here.”

The SMARTFARM program at ARPA-E is directed by Dr. Steven Singer. “The Illinois intensive measurement site is a great example of partnership between ARPA-E and USDA.” Singer said. “The multi-year funding from the USDA NRCS as part of the IRA will allow the ASC group to expand the observations from the initial datasets generated in the ARPA-E SMARTFARM program. These data will provide a comprehensive inventory of greenhouse gas emissions from working farms, influencing models and informing policy.”

Opportunities for expanding collaboration with the Illinois research in nitrous oxide emissions were explored in January, when ASC convened a group of international leaders in soil nitrous oxide research, including some from the USDA and ARPA-E, in Chicago — which ultimately led to the announcement of the N₂Onet to track emissions from agricultural systems.

“Allowing the USDA to see the vision that the University of Illinois faculty has in characterizing and quantifying the fluxes of N₂O in agricultural settings really helped us move to the forefront of this funding opportunity,” Yang noted. “We will use our years of experience in this area to generate an unprecedented long-term record of multi-scale data needed to take the leap forward in our understanding of how to mitigate soil nitrous oxide emissions  ”

As one of two intensive measurement sites in the Midwest (the other in Ames, Iowa), ARS Urbana will be a test bed of making baseline measurements at multiple different scales and then integrating those scales to understand the drivers and the consequences of management practices in current agricultural systems. Ultimately, the team will investigate how various changes in management or land uses can offset some of those greenhouse gas emissions. The funding will enable the collaborators to hire more researchers to further characterize what is happening with soil biogeochemistry, to understand the mechanisms behind greenhouse gas emissions from the soil, to purchase equipment to double or triple activities and provide data necessary for improving model estimates of the impact of practices on mitigation outcomes.

Another stream of USDA funding will support a similar project by faculty in the Department of Natural Resources and Environment Sciences to instrument greenhouse gasses measurements from the Illinois Public Media Tower near Monticello. That project will use regional inverse modeling to study how different urban and agricultural settings are contributing to greenhouse gas emissions, coupling precise measurements of those emissions with weather and climate circulation models.

Bernacchi believes that having resources and the infrastructure to develop data collection, data analysis, and data storage pipelines will leverage future funding opportunities.

“We’re a big gear in an important and impressive machine,” he concludes. “Our intensive measurement site is a strong blend of university and federal scientists. The granularity of what we are going to be measuring at the field scale in terms of really high temporal and spatial resolution all the way to the ecosystem and regional scale will bring us national attention in this effort.”

Kaiyu Guan, the founding director of the Agroecosystem Sustainability Center and Chief Scientist at NASA Acres, has been named one of 18 finalists for the 2024 Blavatnik National Award for Young Scientists. Established in 2007, the award, jointly presented by the Blavatnik Family Foundation and the New York Academy of Sciences, honors exceptional young scientists (age 42 or younger) across the life sciences, physical sciences, engineering, and chemistry, providing critical support to innovative research that addresses global challenges.

Guan was one of 331 nominations from 172 institutions in 43 states. He represents the Agriculture and Animal Science category and is being recognized for “developing revolutionary technology to enhance our understanding of agricultural production systems and innovating transformative solutions to achieve co-sustainability of agricultural productivity.” He will be formally honored at a gala ceremony on October 1 at the American Museum of Natural History in New York.

“Thanks to the Blavatnik Family Foundation for this honor for the second time. The award goes to our whole team for the journey of innovating solutions to ensure agricultural sustainability in the US Midwest and beyond,” said Guan. 

Guan, a Blue Waters Professor of Natural Resources and Environmental Sciences at the University of Illinois Urbana-Champaign, founded and directs ASC, which has a mission to revolutionize agricultural systems through research, collaboration, and engagement, bridging science and practice for agricultural productivity and ecosystem sustainability. He uses computational models, satellite data, fieldwork, artificial intelligence, and supercomputers to enable agriculture to adapt to and mitigate climate change. The approaches spearheaded by Guan enable real-time monitoring of crop growth, water demands, nutrient needs, crop yield forecasts, and environmental impacts of every crop field in the US Midwest and beyond. His agricultural prediction platform is used by the government and farming communities to advance climate-smart agriculture policies and has enabled farmers to shift towards sustainable practices. 

The Blavatnik Award is the latest in a series of honors bestowed upon Guan, which include the 2023 Macelwane Medal from American Geophysical Union and the 2022 FoodShot Global Groundbreaker Prize and being named a 2023 University Scholar by the University of Illinois System.

A multi-institutional study led by University of Illinois and Agroecosystem Sustainability Center (ASC) scientists concluded that, although soil moisture varies significantly both within a single field and from field to field due to varying soil properties and different management practices, soil moisture distribution relative to the field average remains consistent across time within each field. 

Over three years, the team used sensor measurements and a high-density campaign to reveal that the drier areas remain the drier areas and the wetter areas remain the wetter areas. The study also deduced this finding, reliable estimations of high-resolution soil moisture could be made by integrating optical and active microwave remote sensing, and modeling,  instead of relying on infield measurements.

“Our ultimate goal was to improve our understanding of soil moisture variability,” said principal investigator Bin Peng, an ASC scientist and an assistant professor in the Department of Crop Sciences. “We wanted to understand the controlling factors of those variabilities and how those variabilities can be reflected in satellite remote sensing data.”

“The current satellite-based soil moisture products are too coarse to meet the requirements for agricultural applications,” noted Yi Yang, the study’s first author and a doctoral student in computational ecohydrology. “We found that the spatial pattern of soil moisture variability is not changing over the season. In other words,drier areas tend to stay drier and wetter areas tend to stay wetter. We can use this knowledge to estimate the pattern of the spatial variability of soil moisture, and then estimate high-resolution soil moisture products.”

The research team also included Kaiyu Guan, founding director of ASC and a professor in the department of Natural Resources and Environmental Sciences; Ming Pan, a senior hydrologist at Scripps Institute of Oceanography at the University of California-San Diego; Trenton Franz, a professor of hydro geophysics at the University of Nebraska-Lincoln; Michael Cosh, a researcher at the U.S. Department of Agriculture’s (USDA) Hydrology and Remote Sensing Laboratory and Carl Bernacchi, a core ASC scientist at USDA and a professor in the Department of Crop Sciences and Plant Biology. The team conducted field campaigns in three 85-acre fields and set up continuous field stations in 30 other fields from 2021 to ’23. Their results were published on April 26 in the Vadose Zone Journal.

“Most of our efforts were to improve our understanding of soil moisture variability using field experiment data, and we are also striving to test if our improved understanding can really be useful for remote sensing retrieval,” Yang said.

He noted that taking regular field measurements are too expensive, too labor intensive and not scalable.

“We can get the relative dry-wet pattern within a crop field through optical remote sensing,” Peng said. “Therefore, you don’t have to go to the field and replicate the data collection. Our experiment confirmed that because the relative pattern is stable, once you get two or three images from optical satellite sensors to confirm the wetter and drier pattern, you can fill in the temporal gap. This opens a new pathway for high resolution remote sensing retrieval.”

Peng said the study provides a roadmap for studying soil moisture variability in cropland, which until this point had been lacking both measurement and reliable remote sensing capabilities. That pathway combines optical remote sensing data with shortwave infrared spectral bands, active microwave remote sensing, and modeling. High-resolution soil moisture data will be valuable to the farmer for more precision irrigation. It could also be used to understand greenhouse gas emissions or carbon intensity of agricultural production, which are closely related to soil oxygen and water conditions as they directly affect biochemical reactions and microbial activities. 

“We should build upon the knowledge discovered here to develop a high-resolution soil moisture product,” Guan said. “We laid out our roadmap for mapping high resolution soil moisture over cropland using multi-source satellite remote sensing and modeling data. The first stream of information gives within field soil moisture variability, and then the second stream gives the absolute soil moisture temporal changes. We can then integrate them with modeling to map every field across the Midwest or even across the globe.”

As researchers continue to understand the effects agriculture plays in climate and environment, a new research project was recently funded by the NASA Interdisciplinary Research in Earth Science (IDS) program, which includes experienced researchers from four institutions. The new project has for the first time made it possible to show the impact two nitrogen fluxes — ammonia (NH₃) and nitric oxide/nitrogen dioxide (NOx) — have on agricultural productivity and air quality.

The study led by Kaiyu Guan, Director of the Agroecosystem Sustainability Center at the University of Illinois Urbana-Champaign will integrate satellite remote sensing, strategic field work from commercial farmland in Central Illinois, and ecosystem biochemistry modeling to quantify these nitrogen emissions from agriculture across the U.S. Midwest. The goal is to quantify the magnitude of NO_X and NH₃ from these fields to the atmosphere. Being able to use approaches from both in situ measurements and satellite data in biochemical modeling will help corroborate the measurements of each.

The three-year interdisciplinary project brings together atmospheric scientists Mark Zondlo from Princeton University and Kang Sun from the University at Buffalo; ecosystem scientists  Steven Hall from the University of Wisconsin-Madison and Wendy Yang from UIUC; and agroecosystem modelers Guan and Bin Peng from UIUC.

Sun’s team will examine the latest NASA satellite data to understand how to develop new methods to estimate the emissions of these two trace gasses. Zondlo will use state-of-the-art, fast flux sensors to make continuous flux measurements of NO_X and NH3 and also targeted measurements on a mobile laboratory to bridge the field and satellite scales. Hall and Yang, both field-level measurement experts, will measure NO_X at the field level. Guan and Peng will take these measurements and develop the final model.

“It is exciting to work with a team on a project that bridges across vastly different scales and synthesizes across measurement and modeling. This approach is critically needed to advance our understanding of the patterns of agricultural emissions.”  Zondlo commented. 

Ultimately, the goal is to provide improved guidance to farmers on future use of nitrogen fertilizer and alleviation of nitrogen emissions from agricultural practices to improve air quality in agricultural dominated landscapes.

“This is a very unique NASA IDS project,” Guan explained. “We want to take advantage of satellite-based observation, in-situ data, as well as biochemical models to holistically understand the nitrogen cycle. This information has previously been hard to gather.”