ASC-led study reveals stable soil moisture variability within fields and opens the door for satellite remote sensing for future measurements.

One of the experimental fields shortly before planting in early May. [Remote sensing signals can provide reliable estimates of soil moisture without vegetation cover during non-growing seasons. (photo by Yi Yang)

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.

A container in the field housing the data logger connected to soil moisture sensors and communication equipment transmitting data via cellular network. (photo by Yi Yang)

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.”

Photo courtesy University of Illinois College of ACES

Perhaps at first, it was a case of being in the right place at the right time for Lisa Ainsworth, but in the past 20-plus years, she he has left an indelible mark on the advancement of crop resilience to climate change.

In 2001, USDA Scientist Don Ort along with Steve Long and Evan DeLucia, professors in the Department of Plant Biology, built the Soybean Free Air Concentration Enrichment (SoyFACE) Center in Savoy, Ill., to demonstrate the effects of climate change on crops. Ainsworth, then a Ph.D. student in the Long lab, conducted some of the first experiments at SoyFACE.

Today Ainsworth is in her third decade as a federal scientist under the USDA Agricultural Research Service (ARS). She heads the USDA ARS Global Change & Photosynthesis Unit at SoyFACE and continues to work with the trio of founders, scientists from the University of Illinois and other institutions from around the world, and more recently the team of researchers affiliated with the Agroecosystem Sustainability Center (ASC).

“I think there is tremendous benefit in having long-term funding for mission-driven research in a location that is developing cutting-edge practices,” Ainsworth said. “We have access to all of the equipment, the talent of the university, as well our mission through ARS. I actually think it can be the best of both worlds.”

AT SoyFACE, researchers grow crops with altered climatic conditions, which reflect predicted future changes to our climate (Courtesy SoyFACE)

Ainsworth indicates that more than half of the USDA ARS researchers are on university campuses, which has proven mutually beneficial as an epicenter for research.

“This university is especially good at promoting, encouraging and supporting team science,” Ainsworth said. “There have been a number of these experiments around the world, but none have lasted for as long as the experiment at SoyFACE. It’s just one example of two institutions working together to do more than they could do individually.”

As a Ph.D. student, Ainswoth not only studied photosynthesis and its response to rising CO2 concentrations at SoyFACE, but also did the same with oak trees at an open-top chamber experiment at Cape Canaveral, Fla., and conducted face experiments on ryegrass and clover just outside of Zurich, Switzerland. Following a postdoc experience as a Humboldt Fellow in Germany, she returned to Illinois and has built her career at SoyFACE.

Much like ASC, SoyFACE has thrived not only through the cross-disciplinary environment at the University of Illinois, but also because it is in an area dominated by agriculture.

“Initially, Steve Long came to Illinois from the University of Essex in part to start a FACE experiment,” Ainsworth recalled. “He thought that fields in Central Illinois would be pretty homogenous and a good testbed for this pretty new approach. We have been able to ask questions from a fundamental science perspective, but also from an applied science perspective.”

The mission of the SoyFACE experiment has changed slightly over its two decades — from simply demonstrating the effects of climate change to discovering ways for crops to thrive under futuristic climate conditions, such as increased CO2 and ozone, elevated temperature, and drought. Ainsworth studies genetic variation and crop responses to these elements of climate change and has collaborated with soybean breeders, both inside and outside of ARS.

“If we can identify lines that are more tolerant to ozone and more responsive to CO2, and then understand the genetics that are underpinning those responses, we have the ability to design crops in the future that will produce more,” she said. “We are able to study those responses from molecular mechanisms up to ecosystem-level responses.”

SoyFACE also enables studies on how plant-weed interactions and plant-insect interactions might change in the future.

“Measurements of plant responses to climate change provide critical data to feed into our models of future agricultural productivity,” Ainsworth said. “Plant responses to climate change will also in part determine future atmospheric composition and future climate. SoyFACE and other FACE experiments provide ground truth data that is critical to research efforts to model the Earth’s system.”

The partnership with ASC and Founding Director Kaiyu Guan has, among other things, enhanced the modeling component to the research.

“The goal for ASC is to improve the sustainability of agriculture and that is also fundamental to the research that I do,” Ainsworth said of the partnership. “A big piece of that as we look to the future is adaptation to climate change.”

Ainsworth has worked alongside ASC to improve remote sensing for monitoring nitrogen in crops. Guan has also tested solar induced fluorescence (SIF) under different environmental conditions at SoyFACE.

ASC has brought together teams like Ainsworth’s to collectively tackle some of the grand challenges of sustainability in the 21st century and beyond.

“Kaiyu has brought people together that have very different expertise, but a similar motivation, that is the desire to improve agriculture and to adapt agriculture to climate change that is here already and is impending, and increase its sustainability,” Ainsworth said. “It’s one thing to just increase yields and maybe have more inputs, but that’s not going to help us with the state of the planet. We all understand the need for a systems-level approach to adapt to any change that we make. With Kaiyu at the helm, the sky’s the limit.”

Jonathan Coppess was named the Leonard and Lila Gardner Illinois Farm Bureau Family of Companies Endowed Associate Professor in Agricultural Policy in an investiture ceremony on September 14, 2023. (Photo by Fred Zwicky / University of Illinois Urbana-Champaign)

Jonathan Coppess plays a valuable role in ASC by informing research findings to policymakers and other governmental officials.

The Director of the Gardner Agriculture Policy Program and Associate Professor of Law and Policy for the University of Illinois’ Department of Agricultural and Consumer Economics, grew up on a farm in Ohio. After earning a Juris Doctorate degree from The George Washington University School of Law and practicing law in Chicago, he found his way back to agriculture through the policy space, where today he helps provide a valuable link from research to policy.

Coppess helps provide ASC scientists bridge the gap between research and policy, often interpreting their research to inform policymakers.

“I think ASC scientists, such as Kaiyu’s interest in policy, is phenomenal,” Coppess said. “It’s great to work with a researcher who has the perspective that research can be important for not just the academic value of it, but can also move policy, which can open up new research questions.”

Coppess sees his role as more of an interpreter rather than as an advocate or lobbyist. Although he doesn’t do the basic research, he helps apply research to policy questions, informing policymakers and their staff, farmers, and interest and stakeholder groups. That kind of work has invigorated him.

“For someone that doesn’t have the ability to do the research — but is curious about it and has a fascinated interest in it — I get a chance to find ways to incorporate that research into the work I do in the policy arena,” he said. “The application of research and policy is a challenge at times. Policy moves on a different time frame, but there’s always a need. Trying to figure out how to meet that need is actually fun.”

Coppess brings an impressive resume to his work with ASC. He served as Chief Council for the U.S. Senate Committee on Agriculture, Nutrition, and Forestry and played a lead role in the development of the 2014 Farm Bill. More recently, he served as Special Counsel for the U.S. Senate Committee on Agriculture, Nutrition, and Forestry where he assisted in the development of the Build Back Better Act, legislation that lays the groundwork for climate-smart agriculture and conservation policies. He also volunteered for the U.S. Department of Agriculture’s (UDSA) Agency Review Team as part of the Biden-Harris Transition Team in 2020-21.

On a full-time basis, he engages with farmers and policymakers on agriculture policy both in person and through the farmdoc daily and Policy Matters platforms — all while providing award-winning instruction to University of Illinois students, introducing them to public policy and the principles of policymaking.

Coppess’s road to UIUC, began in 2005, when he decided to pivot from his law practice.

“I’ve always liked politics, government and history and was really interested in some of the work my friends were doing on the Hill in the Senate,” Coppess recalls. “So I decided to try for that and eventually landed a job in the U.S. Senate.”

Coppess spent eight years in Washington, six of them in two stops with the Senate, and two years with the USDA. His experience in legislation and policy making gave him an intimate look at how bills were crafted and negotiated, which ultimately led to his current opportunity at the University of Illinois in 2013.

“They were looking for someone who wanted to focus on agricultural policy,” Coppess recalls. “To say it was a unique opportunity, understates it. It was an amazing chance. I always kind of joke that particularly when you are working in Congress, you’re running 100 miles an hour and everything is about an inch deep. Every day I felt like I was keeping a mental list of questions. One of the things that this position has allowed me to do is to take some deeper dives into policy issues and its development through history.”

His interest in both agriculture and history converged with the publication of his book, The Fault Lines of Farm Policy: A Legislative and Political History of the Farm Bill in 2018.

“The book is the product of all of those questions I had while working on the Hill,” Coppess said. “I just got lost in the history and trying to sort out which thing led to which issue. The regional issues were very clear, but I was struck by how long standing they were and was interested in how it plays out.

Jonathan Coppess’ book, The Fault Lines of Farm Policy: A Legislative and Political History of the Farm Bill, provides perspectives for future policy discussions and more effective policy outcomes. (Courtesy University of Illinois College of ACES) 

“When I was on the committee writing the bill that ultimately became the 2014 Farm Bill, I remember running around counting votes and using different spreadsheets to figure which votes we might gain and lose with a particular amendment. To see how historically these coalitions really accomplished the vote counting and how that, time and again, is a critical factor in how the policy developed, is really interesting.”

Coppess points out that although there is a long history of bipartisanship within the agricultural farm policy arena, much of the divide actually occurs over regional lines.

“The ugly reality of our politics today is that nothing escapes partisanship for long or completely,” he said. “However, there is a lot of crossover appeal where you are helping farmers and low-income families and looking at environmental issues and air and water quality.”

In terms of his work with ASC, he says that modeling, in particular, lends itself to some of these policy questions — especially when it comes to climate change.

“There are some fascinating things that Kaiyu’s research could inform,” Coppess said. “You can present outcomes and scenarios and use this research to open or expand the conversation away from one thing or another to a variety of options.”

After that, Coppess says the goal is to not only let people have a chance to make up their own mind, but also test their ideas. That feedback leads to more discussion and a wider range of ideas, which can be beneficial to the researcher, the policymaker, and the farmer.

“It feeds on itself,” he said. “One conversation leads to another set of questions that could lead to the next six conversations.”

Besides climate change, another hot issue (which is semi-related) is risk assessment, particularly when a farmer decides to change course from his normal practice. All of it gets to the bottom line (dollars and cents).

“The risk issues are huge,” Coppess said. “Change in those practices come with management risks as well as yield variance.”

He notes that policymakers don’t want to be the one to advocate for a policy that has major negative implications for the farmer. The farmer, in turn, is wary of making more bold changes than his neighbor that might risk not being able to pay the mortgage note.

ASC’s modeling and computational capabilities will be particularly helpful to run scenarios on those potential changes and to illustrate some of the challenges, for instance, around climate change and cover cropping. This can help farmers and policymakers shape future decisions.

“Analyzing risk and managing risk is a huge part of what a farmer does year in and year out,” Coppess notes. “Therefore, making sure practices are modified from an informed perspective is really critical. What’s unique to this industry is that if you make a mistake in the farm field, the whole year is gone. We will be able to run scenarios for the farmer and not have to wait five years to see the outcomes because they will have so much research to back it up.”

In addition to informing decisions, those meetings also help support the value of the research in the first place.

“We are helping policymakers understand that when they invest in research, over time we find different ways to use it,” he said. “It’s a good example of how that system plays out. It has value to them. It obviously has value to the university because it helps keep research funding going. It can improve policymakers’ understanding of what research funding can do.”

Coppess is excited to see what impact ASC can play in shaping agriculture going forward and feels fortunate to play a role.

“The opportunity to work directly with researchers and explore how their research findings can inform policy and how we can creatively shape those policies is rewarding,” he said. “It’s been a really amazing journey from working on policy to getting into the weeds of how research can be applied to it.”

Leadership from NASA, ASC, the College of Aces, the Institute for Sustainability, Energy, and Environment gathered to present the Earth Science and Agricultural Research symposium on April 23, 2024 at the National Center for Supercomputing Applications (photo credit Mike Koon)

The Agroecosystem Sustainability Center, the Institute for Sustainability, Energy, and Environment, and the College of Aces collectively hosted about a half dozen representatives from NASA, including Tom Wagner, the Lead for NASA’s Earth Action consortium, and Alyssa Whitcraft, the Executive Director of the NASA Acres program, on the University of Illinois campus on Tuesday, April 23.

Through a morning Earth Science and Agricultural Research symposium at the National Center for Supercomputing Applications (NCSA), a two-hour roundtable with key stakeholders, and an afternoon visit to the Energy Farm, leadership shared ideas and explored ways to further partner with ASC, Illinois, and the state’s farm community.

Keynote speakers for the event were (l-r) NASA Earth Action Program Lead Tom Wagner, University of Illinois Vice Chancellor for Research and Innovation Susan Martinis, ASC Founding Director and NASA Chief Scientist Kaiyu Guan, NASA Acres Executive Director Alyssa Whitcraft, and University of Illinois College of ACES Dean German Bollero. (photo credit Julie Wurth)

NASA Acres was formed in 2023 to bridge the gap from space-to-farm and education-to-impact together with U.S. farmers, ranchers, and other agrifood system decision makers who collectively address the most pressing challenges to sustainable, productive, and resilient agriculture. Whitcraft and ASC Director Kaiyu Guan, the consortium’s chief scientist, have been working together for a number of years even before coming together to form a significant part of NASA Acres leadership.

The event brought together many of the key stakeholders – NASA, ASC, university research and innovation leaders, area farmers, legislators, the Illinois Farm Bureau and other agriculture agencies. Those stakeholders explored ways they could synergistically form partnerships and efficiently provide actionable data and tools to farmers to help them make effective decisions. The partnership will also inform how researchers can effectively answer pressing questions and needs of the farmer.

(Left) a satellite-based NOx emission map from TROPOMI derived by Kang’s group, which shows detailed sources of NOx in central and southern US (image credit: Kang Sun); (right)The fast flux sensors, developed by Zondlo’s group, to make continuous flux measurements of NH3 for this project (image credit: Mark Zondlo) .

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 NOX 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 NOX 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 NOX 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.”

Locations and site images of the SIF systems (Image credit: Genghong Wu).

In recent years, the scientific community has increasingly turned its attention to sustainable agriculture, aiming to maximize crop yield while minimizing environmental impact. A crucial aspect of this research involves understanding the fundamental processes of plant photosynthesis and how they can be monitored at scale. One promising method for assessing photosynthetic activity is through the measurement of sun-induced chlorophyll fluorescence, a byproduct of photosynthesis that can be detected from ground-based sensors as well as from satellites in space.

The study led by Genghong Wu, a PhD student advised by Agroecosystem Sustainability Center (ASC) Director Kaiyu Guan,, and others utilized ground-based instruments to measure far-red SIF and various vegetation indices (VIs) that reflect plant health and activity. It compiled 15 site-years of SIF and VIs data from various crops (corn, soybean, and miscanthus) over a span of six years (2016-2021) within the U.S. Corn Belt (Illinois and Nebraska). Their results are published in Scientific Data.

“Eddy covariance towers are currently the gold standard for measuring canopy photosynthesis ,” Wu explained. “However, they are expensive and are distributed over limited sites across the globe. Satellite SIF can provide us spatially continuous data. However, fully utilizing satellite SIF for photosynthesis monitoring requires a mechanistic understanding of the relationship between the two.”

This comprehensive dataset provided in this study can be used to gain insights into the mechanistic relationship between far-red SIF and canopy-level photosynthesis. This relationship is critical for interpreting SIF readings accurately, whether they come from ground-based observations or satellite imagery. Importantly, the study provides a robust dataset that can serve as a benchmark for validating satellite SIF products, which are increasingly used to monitor global agricultural systems and carbon cycling. Moreover, the dataset can be used to improve models for predicting crop yield and assessing plant health on a large scale, contributing to more informed agricultural practices and policies.

“We are one of the first groups worldwide to develop such a network for long-term SIF measurements, dated back to 2016”, commented by Guan. “It was a huge team effort with multiple PhD students and postdocs for the past 7 years, thanks to funding from multiple funding agencies, including NASA, DOE, and NSF.”

“One of our goals was to provide researchers a broader application of this data set,” Wu noted.

“Thus, this paper provides a detailed description of  how we collected, processed and indirectly validated the datasets and what are the potential applications of the data.”

Wu also points out that while many researchers collect SIF and photosynthesis data, there isn’t a standard method for doing so.

“People have collected and processed the SIF data in different ways,” Wu said. “There are several systems with different instrumentation designs. We needed a detailed record of our systems and set-up to hopefully be helpful for setting the standard for collecting and processing this data in the future.”

“We decided to be transparent with our method so that others can trust the reliability of our data.” Wu said. “ They can also now use our SIF data to assimilate the land surface models to estimate the carbon cycle or the water cycle in addition to photosynthesis estimation and stress detection.”

Other investigators on the project included Hyungsuk Kimm and Chongya Jiang from the University of Illinois Urbana-Champaign (affiliated labs within the College of Agricultural, Consumer, and Environmental Sciences (ACES), the Department of Natural Resources and Environmental Sciences (NRES), the DOE Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), and the National Center for Supercomputing Applications (NCSA) and Xi Yang from the Department of Environmental Sciences at the University of Virginia as assistance from members of the Research Institute of Agriculture and Life Science at Seoul National University, Republic of Korea,

Wendy Yang – Professor of Plant Biology (Courtesy University of Illinois News Bureau)

What stood out about the University of Illinois Urbana-Champaign when Wendy Yang interviewed for a tenure-track faculty position in its Department of Plant Biology a decade ago was the institution’s trademark collaborative nature. A decade later, in that environment, she and her collaborators are making their mark in solving some of the globe’s most pressing climate issues.

“I realized immediately that Illinois is a unicorn institution,” she said. “I met world-class scientists in so many disciplines who don’t have egos, who work together and are collaborative with no walls between units on campus. I’ve been here for 10 years and I’m glad that first impression was accurate.”

That collaborative environment was instrumental in the establishment of two major centers headquartered at Illinois, in which Yang is a core figure — the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), now in its seventh year and its second round of funding, and the Agroecosystem Sustainability Center (ASC), now in its third year. Yang is Associate Director of ASC and Sustainability Theme leader for CABBI.

It is that against backdrop where Yang has established her research lab and is working to tackle global climate issues, such as mitigating soil nitrous oxide emissions.

“I’ve been working to understand soil nitrous oxide emissions since even before my first day as a graduate student,” noted Yang, who holds a B.A. from Harvard University and a Ph.D. from University of California-Berkeley. “What piqued my interest has been the fact that it has been a tough challenge for the scientific community for decades. Although scientists have known some of the processes that have produced nitrous oxide emissions since before the 1900s, and there have been hundreds if not thousands of studies on these processes, we still can’t predict these emissions in the field. That’s something we need a better understanding of if we are going to successfully mitigate nitrous oxide emissions from agricultural systems.” 

Yang points out that part of the dilemma is that up until now much of the research to understand drivers of soil nitrous oxide emissions has been done in a controlled environment in laboratories. The U.S. Department of Energy funding through ASC’s SYMFONI and SMARTFARM projects has not only brought the research to the field, but allowed the purchase of 20 chambers distributed throughout the field that automatically measure soil nitrous oxide emissions each hour. 

“When you go outdoors, soil conditions are very complex,” Yang said. “Thanks to this project, we’ve been able to produce unprecedented high-spatial, high-temporal resolution data sets on nitrous oxide emissions. It has been a dream project for me. No one else has been willing or able to invest that much funding in one field, but that’s what we need.”

Her team has discovered that even within the confines of a single field, the nitrous oxide emissions are varied — some places higher and some lower. That, among other things, has helped inform management practices where researchers can target the hot spots. 

The collaborative nature of ASC has meant researchers aren’t doing their work in silos, which has been important in helping make recommendations to farmers in areas such as cover cropping. While Yang’s team is looking at its effects on nitrous oxide emissions, ASC Director Kaiyu Guan, Associate Director Andrew Margenot, and DoKyoung Lee, professor of crop sciences, are also doing cover cropping work and can share their findings with Yang’s group.

“A big challenge, especially for the farmers, is increased volatility in precipitation,” she said. “Not only are we getting more intense spring rainfall, but now we’re also getting  drought  that makes it so difficult to not only manage crop productivity, but also to attain the intended sustainability outcomes of climate-smart agricultural practices.” 

Yang’s group is currently conducting a meta-analysis to evaluate trade offs in the soil carbon benefit from practices versus unintended effects on soil nitrous oxide emissions.  While cover cropping might reduce carbon emissions, it might also increase nitrous oxide emissions, which Yang notes is 300 times better at trapping heat than carbon dioxide. 

“A small increase in nitrous oxide emissions may completely offset the climate change mitigation benefits of the soil carbon gains,” Yang said. “What we have learned from our SMARTFARM research is that greater soil organic carbon availability is part of what makes these nitrous oxide hot spots hot.”

Yang shares Guan’s vision of a future where scientists can not only analyze 20 different spots within a field but scale that up to regions, countries, and even the globe.

“What excites me about Kaiyu’s work is that he is crossing that scale from meters to hundreds of kilometers,” Yang said. “We aim to discover predictive variables that can be remotely sensed and scaled from one field to across regions.” 

In that vein, Yang has taken her studies to the area of the globe that is responsible for the highest naturally produced nitrous oxide emissions — tropical rain forests. That’s because nitrous oxide naturally occurs in soils that lack oxygen. Because the rain often pushes the oxygen out of the soils, it encourages the process of nitrous oxide there. 

“One of the reasons I love studying nitrous oxide is that while there are really important questions we need to address in agricultural systems here, we are also indirectly affecting natural emissions. My work has importance everywhere,” Yang said. 

“When I first started in this field some 20 years ago, we were a bit more concerned about the industrialization of the tropical regions and how the nitrogen deposition we’ve seen in temperate industrialized countries was coming to these tropical areas. We wanted to understand how indirectly fertilizing these areas could change tropical nitrogen cycling. We weren’t considering management of tropical forests, but more so representing those changes in our models. Everything that goes into our Earth system models is crucial for predicting future climate change.”

Part of the challenge in reducing nitrous oxide emissions is reversing the cycle. Half of the increase in atmospheric nitrous oxide concentrations comes from human activity, which has resulted in both increased rains and drought. Yang notes that it directly affects the nitrous oxide emissions that occur naturally not only in rainforests, but elsewhere as well. 

“We expect that as the amount of reactive nitrogen we put into the atmosphere increases, it either rains out or it settles out and it fertilizes even our natural ecosystems,” Yang noted. “So even when humans are not having direct impacts on nitrous oxide emissions through fertilizer application, we are still indirectly fertilizing our natural ecosystems, particularly in areas near industrial activities. There have even been studies which show that near roadways, emissions coming out of the tailpipes of cars end up depositing near the roadways.” 

Image Credit: Wendy Yang

“There is currently a lot of interest in climate smart agriculture with start-up companies emerging and industry leaders pouring funds into this,” Yang added. “I think everyone wants an easy solution, for instance sprinkling microbes on the soil, that would fix our problems for us. However, I think we are realizing that there is a reason why those microbes aren’t surviving naturally or dominating naturally in agricultural soil environments. We need to broaden our focus in developing technologies to reduce the nitrous oxide emissions.”

Which is why it has been important for Yang’s group to work closely with that of Margenot, whose focus is also on soil composition, and with Guan and Jonathan Coppess, who can work closely with politicians on areas such as government subsidies to make these climate practices cost-effective for the farmer. 

Yang is excited about what future collaborations could mean in helping solve these global climate issues. She has been doing team science leadership training through the Carl R. Woese Institute for Genomic Biology. 

“We learned that when you build a team, you need to have team members who work well together, not necessarily just the best and the brightest,” she said. “Our success with CABBI shows that at the University of Illinois we know how to function at that large scale, and we know how to build teams that work well together.” 

While the collaborative nature of ASC shows its benefits in research, it also benefits from being at the heart of the study area – the Midwest – and its understanding of bringing to the table the most applicable piece to the puzzle: the farmers. 

“Through DK and Andrew’s relationships with the farmers, we have insight into the actual challenges of the farmer,” Yang said. “We understand the importance of trying to come up with solutions that are not counterproductive to the livelihoods of the farmers.

“I think one of the strengths of our ASC team is that because we have people looking at the same problem from different angles, we can see the tradeoffs, whereas other people may have blind spots because they are only looking at it from one angle,” she said. “Because at ASC we have people from many disciplines working together as a team, we can holistically address these questions.”

With the core group of ASC researchers, including Yang, transitioning from early-career to mid-career scientists, it produces a unique energy. 

“We are on the upper trajectory in our research programs,” Yang noted. “We are finding a lot of overlap in our visions for not only what we want to accomplish as scientists, but also the impact we want to have on society. One of the exciting parts for me is that when we put all that energy together and it’s all going in the same direction, there is so much we can accomplish. We all have big dreams.”