ASC Associate Director Wendy Yang Finds Collaboration Environment Essential to Tackling Nitrous Oxide Emissions

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.”

Margenot profiling soils in coffee agroecosystems in Guatemala. This work, conducted via participatory research with smallholder farmers, seeks to identify means to increase coffee yield and quality to improve smallholder income in a region that is largely economically dependent on this tropical crop.

To find the dirt on Andrew Margenot, you may need to sift through the literal dirt. Currently an associate professor of soil science, Margenot specializes in soil biogeochemistry to understand agroecosystem functions such as nutrient storage and cycling, crop production, contaminant filter and storage, and climate regulation. 

His research team of 40 personnel has approximately 35 active grants, with 80 percent of those projects focused on the Midwest context. The emphasis of this work is on nutrient management, soil organic matter cycling and soil health, involving direct work with stakeholders ranging from USDA NRCS to farmers via a lot of on-farm research.

“We are interested in understanding outcomes of practices: why is a practice working or not for a given outcome of interest?” Margenot explained. “Can we explain those outcomes in order to predict future outcomes? We work with the Agrosystem Sustainability Center (ASC) to assess and explain those outcomes and study the biogeochemical mechanisms that underpin agroecosystem functions.” 

Although the University of Illinois sits in the heart of some of the richest soils in the world, Margenot cut his teeth on high weathered, low fertility soils in the tropics, notably East Africa and Latin America. 

“The soils in these parts of the tropics have low fertility because they are old,” Margenot explained.”It’s like a 95-year-old person.”

Having studied on the coasts, with a bachelor of arts degree  from Connecticut College, majoring in both philosophy and biochemistry and molecular biology, and a PhD in soil biogeochemistry from UC Davis, he thinks there are several misconceptions there about the Midwest.

“ I think that we as a field of research have mistaken ecological simplicity of the Midwestern agricultural landscape with biogeochemical simplicity. It’s not simple, and the problems we face are not easily solvable,” he said.

A current topic of focus is nutrient management, focused both on improving fertilizer use efficiency and how nutrient losses practices can maximize efficiency and minimize losses, and why.

Margenot stands in a soil pit next to Jim Isermann at Isermann Farms in LaSalle Co., IL. The pit profiles the official state of Illinois soil, the Drummer series. Essential to the approach taken by Margenot’s team is start with farmers, be they in the Midwest or in Guatemala or Kenya, to understand the challenges that agroecosystem managers face and how researchers can better align scientific approaches to target real-world solutions.

“As part of that, we build a lot of tools to understand the system and test mechanisms,” he added. “If you don’t have a tool, you have to build it to understand why something is changing.”

Such as finding the right level of phosphorus in the soil to support high crop yields while reducing run-off losses. Margenot calls phosphorus the “Goldilocks nutrient” because it is hard to get it “just right”. Margenot’s team has also discovered that in assessing the nutrient losses to the surface water, researchers have not been accounting for natural losses through eroding streams. 

“A portion of our phosphorus losses are due to practices from 60-80 years ago,” Margenot said. “We call these legacy phosphorus. We have a really poor understanding of legacy nutrient losses, but the problem is that is what is driving our losses today. So it’s an inexact science.”

Although headquartered in central Illinois at the state’s flagship land grant campus, Margenot diversifies his research across fields in northern, central and southern Illinois, the greater Midwest, and in the tropics. 

“In order to make our findings and discoveries applicable globally, we try to understand the why of things,” he said. “Even in Illinois, you go from a very cold climate to the beginning of a nearly  subtropical climate. We tend to be spoiled here because even the ‘lesser’ soils in southern Illinois are still very fertile compared to weathered soils in the tropics.  If we can explain how soils function at a biogeochemical, process-based level, then those same insights can be applied to understand soils and agroecosystem functions anywhere, from the red oxisols of Kenya to the black mollisols of Illinois.”  

Margenot also uses this approach to demonstrate that while one agroecosystem management practice may work well in one context, positive trade-offs  are not necessarily universal. For example, cover crops might increase yield in places with marginal soils like southern Illinois or Missouri, but might not in areas where soils are richer.

“Cover cropping is in some ways a Swiss Army knife: you can customize cover crops for all kinds of outcomes,” he added “Are there benefits of using cover crops to reduce soil erosion by wind or nitrate leaching? Absolutely. That’s what we should be thinking about cover cropping in the ‘flat and black’ in the heart of the Corn Belt. In the rolling ground of the Ohio River Valley that bounds the southern extent of the Corn Belt, we know that cover crops increase yield – in contrast to the central Corn Belt – while  also mitigating soil erosion by gravity.”

A severely eroding streambank in southern Illinois. Streambank erosion is an overlooked but critical contribution to non-point phosphorus and sediment loads to surface waters. Margenot’s team is leading an ASC project to quantify – for the first time – streambank erosion and its contributions to P loads in Illinois. These results will directly inform Illinois and US EPA strategy on improving water quality in the Midwest and the Gulf of Mexico.

That is an example of the kind of innovative research that Margenot and others at ASC hope can improve processes and outcomes in both Illinois and around the globe. They are at the forefront of addressing the growing problems of climate resilience and food security. 

On the microscale, he is teaming with ASC to help update the Illinois Agronomy Handbook, where some of the recommendations are more than 80 years out of date. The project is funded by the National Science Foundation (NSF) and the National Research and Education Network (NREN).

“We aren’t great at keeping up with understanding these systems because we are not keeping up on the basics on how we manage them,” he reasoned. “The amount of phosphorus, potassium, and nitrogen recommended for fertilizer are based on efforts from the 1960s.”

Margenot also notes that much of the recommendation is from sampling the top six inches of the soil. Their updates will include results that will account for soil specific reserves of nutrients at the root level some three to four feet deep. Margenot’s team is applying biogeochemistry to understand fertilizer fate, use and non-fertilizer soil contributions to crop uptake. 

“The idea here is to understand how the biology of soils and native reserves in the subsoil can contribute to crop uptake,” Margenot said. “To me, that’s where agroecology becomes good agronomy, and offers a more biologically inclusive approach to nutrient recommendations to improve the farmer’s bottom line. With co-benefits to water quality. That’s something the traditional agronomy approach has missed, and many ecologists have turned their nose up in favor of more pristine, unmanaged ecosystems. I think the agroecosystem is where the action is at, and frankly, the need.” 

On the environmental side, Margenot’s team is part of an ASC Illinois NREC project, which  is gathering data on erosion of streambanks and resulting phosphorus loading across the major and representative HUC-8 watersheds of Illinois. While studies of Baltic Sea basin states like Germany and Poland, have found that one-third of their entire phosphorus loss have come from eroding stream banks, no such data exists in Illinois. The United States Environmental Protection Agency has mandated that by 2025, states and federal agencies report on progress toward achieving programmatic commitments. This study will directly inform the Illinois Nutrient Loss Reduction Strategy, the report from the State of Illinois. 

“If we have a similar result as our colleagues in the Baltics, we will need to reallocate resources in order to solve the problem,” Margenot said.  

As ASC strives to be a global leader in monitoring and modeling agroecosystems for improving sustainability under climate change, Margenot’s team will be valuable in bringing research to understand the role soil plays.

Magenot concluded, “Applying basic biogeochemistry with a systems approach can provide insights to help close gaps that have only grown over the last 50 years.”

Kaiyu Guan is a researcher with lofty goals – he hopes to monitor, model and ultimately optimize every farmland. Guan aims to achieve these goals in the coming decade or so. He’s a researcher with a mission; of helping create tools so farmers can check on and manage their crops – every single field – in real-time to maintain a healthy and productive growth cycle. But simply reaching that goal isn’t enough. Guan also hopes to achieve co-sustainability of environment quality and food security. It’s quite the task, and he’s been using the supercomputing resources at NCSA to tackle the issues surrounding both aspects of his mission, one piece of research at a time. He’s also in the unique position of being one of the researchers at UIUC who’s had experience using NCSA’s retired supercomputer, Blue Waters, and its new cutting-edge GPU-processing resource, Delta.  

Read more about Blue waters here.