Category: Leverhulme Centre

Applying ground-up silicate rock to Midwestern farm fields can capture significant amounts of carbon dioxide and prevent it from accumulating in the atmosphere, according to a new study that successfully quantified those climate benefits for the first time.

Working with Eion Corp., researchers at the University of Illinois Urbana-Champaign and the Leverhulme Centre for Climate Change Mitigation (LC3M) developed a new method to calculate the CO₂-reduction potential of basalt rock amendments applied to cropland soil, a process known as enhanced weathering.

Traditional row-crop agriculture releases sizable amounts of soil-derived carbon to the atmosphere as CO₂, a greenhouse gas that is a primary driver of climate change. With enhanced weathering, silicate rock is applied to farmland to capture that carbon before it reaches the atmosphere. As the rock weathers, calcium and magnesium are released and react with dissolved CO₂ to produce bicarbonate, essentially locking up the gas and redirecting it harmlessly into groundwater.

Quantifying its carbon-capture potential, however, has been a challenge — until now. The Illinois team was able to calculate both the weathering rate and carbon dioxide reduction potential of the basalt rock amendments applied to maize and miscanthus fields. Those factors are critical for efforts to optimize carbon sequestration and for farmers hoping to earn carbon credits.

“In addition to reducing emissions, we desperately need effective ways to draw down atmospheric carbon dioxide. Our results suggest that basalt application to farms could be a win-win for farmers and for the planet, improving yields and drawing down CO₂,” said study co-author Evan DeLucia, Director Emeritus at the Institute for Sustainability, Energy, and Environment (iSEE), G. William Arends Professor Emeritus of Plant Biology, and Co-Investigator at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) at Illinois.

The breakthrough — the result of a five-year study at the Illinois Energy Farm — was published in Global Change Biology Bioenergy. The study was led by DeLucia and Ilsa Kantola, Research Scientist at iSEE and the Carl R. Woese Institute for Genomic Biology (IGB).

The work is part of iSEE’s partnership with the Leverhulme Centre at the University of Sheffield in the United Kingdom, which is investigating enhanced weathering for carbon dioxide removal in field sites around the world: Malaysia, Australia, the U.K., and the United States.

In this case, researchers repeatedly applied finely-ground basalt on twin fields at the Energy Farm for four years — one field with a maize/soybean crop rotation and the other with Miscanthus x giganteus, a perennial grass that is emerging as a productive bioenergy crop to replace fossil fuels.

Grinding the basalt accelerates a natural weathering process that involves two chemical reactions. First, atmospheric CO₂ dissolves in rainwater to create carbonic acid. Then, the acid reacts with the rock dust in the soil to form bicarbonate, a soluble compound that leaches with soil water; that redirects the CO₂ from the atmosphere to the water cycle, where it can pass harmlessly into waterways and potentially help fight ocean acidification. Basalt contains both calcium and magnesium as well as phosphorus and minor nutrients that are released during weathering and benefit soil fertility.

The Illinois team calculated the CO₂ reduction and weathering rate of the basalt by measuring the change in rare earth elements in the soil with the addition of basalt and comparing it to the calcium and magnesium in the system. The rare earth elements are “sticky,” building up in the soil in tiny amounts as more basalt is applied, and calcium and magnesium are released by weathering, with some taken up by the crops. The difference in rare earth elements indicates how much basalt, and therefore how much calcium and magnesium, has been applied; and the difference between the expected amount of calcium and magnesium and the actual amount in the soil tells researchers how much has been consumed by reactions in the soil.

The calculations showed that enhanced weathering reduced net carbon loss to the atmosphere by 42% in maize plots. Paired with conservation tillage or cover crops, the basalt application could turn maize into a net carbon sink. In miscanthus plots, which already stored more CO₂ than they emitted before the addition of basalt, enhanced weathering more than doubled carbon storage. The finding adds to the potential climate benefits of this renewable bioenergy crop, one of three targeted by CABBI in its U.S. Department of Energy-funded work.

Carbon dioxide removal methods are a critical part of climate mitigation strategies, and as social and political efforts to reduce carbon emissions to the atmosphere are delayed, pressure is growing to implement these strategies soon.

Farmers, landowners, and others seeking carbon credits all want to know how much basalt rock to apply and how long the effect will last, both of which depend on the composition of the rock and the environmental conditions where it is applied.

“As we look for new ways to offset carbon emissions, we need to be able to quantify those carbon savings to better compare our options,” Kantola said.

Co-authors on the paper included Professor Carl Bernacchi of the Department of Plant Biology at Illinois, CABBI, and the USDA Agricultural Research Service; Illinois researchers Elena Blanc-Betes of iSEE and CABBI and Mike Masters of ISEE and Plant Biology; Elliot Chang, Alison Marklein, and Adam Wolf of Eion Corp; Caitlin Moore of the University of Western Australia and former CABBI postdoc; Adam von Haden of the University of Wisconsin-Madison and former CABBI postdoc; and Dimitar Epihov and Professor David Beerling of LC3M.

— Article by iSEE Communications Specialist Julie Wurth

Mike Masters, Field Research Specialist for the Leverhulme Centre for Climate Change Mitigation (LC3M), is no stranger to sustainability or to the University of Illinois — in fact, he’s been with both since the very beginning.

“I’ve been around forever!” Masters said proudly of his alma mater. “In the academic world of short projects and high turnover, 10-plus years in once place sure seems like it.”

In 2005, Masters graduated from Illinois with a B.S. in Integrative Biology (IB), or “big-picture biology” — not only that, but he was part of the first-ever class of undergrads to do so. (Departmental rearrangement had recently divided programming into molecular and cellular biology (MCB) and the newly created IB.) Shortly thereafter, he chose to stick around the Champaign-Urbana campus to pursue an M.S. in Plant Biology.

“I was always interested in biology,” he said. “The process of life and ecosystem science in general has always been one of my passions.”

While pursuing his Master’s, Mike studied topics such as nutrient cycling and biogeochemistry. His research was primarily focused on a New Hampshire long-term ecological research site called Hubbard Brook Experimental Forest, where he conducted field work on insect-plant interaction.

After a December graduation, Masters had little time to rest before starting work in January — and luckily, he didn’t have far to travel. His first full-time position involved working alongside iSEE Baum Family Director Evan H. DeLucia at what was then the Illinois Energy Biosciences Institute (EBI). At EBI, Masters compared and contrasted perennial grasses with their annual counterparts — like corn and soy — to determine the ecosystem consequences of going from conventional row crop agriculture to perennial grass biofuel crops. He spent most of his time out on the Illinois Energy Farm, “a world-premiere field site and wonderful place to work.”

“I really enjoyed school, and I enjoyed science, so I saw myself in that role. But I don’t know necessarily if I envisioned myself being a scientist, at least not early on,” Masters said.

Even so, his next step advanced his career not only as a scientist, but as a scientist working on the Energy Farm. After staying with EBI for its full eight-year lifespan, Masters joined DeLucia with iSEE’s newly funded LC3M project. Stationed in the heart of America’s agricultural ecosystem, the U of I team is the “midwestern temperate deployment” of LC3M. And while research is being conducted across the globe from Malaysia to India, to Sheffield, England, all LC3M team members are devoted to the study of one process: enhanced weathering.

Enhanced weathering, so coined as the objective is to increase the rate of the naturally occurring process of rock breakdown, is the practice of applying ground-up basalt — essentially, “rock fertilizer” — to agricultural systems. In theory, this process sequesters CO₂ in the soil while also providing secondary benefits to crops such as micronutrient fertilization and an increase in soil pH. While the LC3M’s research is brought into sharp relief by climate change and the need to curb carbon emissions, the process of weathering itself is ancient history.

“A lot of the actual measurements I’ve been making at the Energy Farm, closing nutrient budgets, sampling water from tile drains, people have been doing for many years,” Masters said. “In this case, it’s the application that’s new and interesting, not necessarily the technology.”

Currently, the Illinois team is applying basalt rock to two crop systems: the standard Midwestern corn/soy rotation, and a single variety of perennial grass. The goal for both experiments is to “apply a very high rate of rock on an annual cycle,” and quantify the results over a five-year timespan. These results, Masters, said could have far-reaching implications.

“In graduate school I worked in forests, and believed that that’s where all the science was,” he said. “But this corn-soy system that we have is the largest biome in the continental U.S., and it’s really exciting to be working on an area with such an impact. This current weathering project is literally scalable to the entire agricultural region. The potential impacts could be really big.

“I’m very happy with where I’m at. I think I’ve found a niche for me that works really well.”

His specific niche on the Leverhulme project revolves around his role as a Field Technician — a role “dictated by the growing season and the cycle of what happens in the field.

“I spend a lot of time in the cold, sampling water in the spring and early winter, and I spend a lot of time in the heat collecting biomass,” he said.

Intense manual labor aside, Masters also appreciates the mentally challenging aspects of his position, as well as the diverse day-to-day tasks and responsibilities that keep him on his toes. But despite the challenges, the end result makes it all worth it.

“It has been challenging at times, but that’s the nature of research,” he said. “That’s why we do these things. If we already knew the answers, we wouldn’t have to do the work.

“There’s not going to be one technological advancement or one cure-all that solves climate change. It’s going to be a number of local solutions, of people beginning to understand the problem and wanting to work toward something better.”

Luckily, projects like the LC3M contain researchers like Masters, who have sided with sustainability from the beginning. They not only understand and care about the problem, but are out in the field year-round working hard in pursuit of a solution.

And while his roots run deep in Illinois, LC3M research will help realize those solutions all around the world.

Read the full research profile of LC3M researcher Ilsa Kantola.

Read a Q Magazine article about Dr. Kantola and the Leverhulme. 

— Article and Photos by iSEE Communications Specialist Jenna Kurtzweil