Salk Scientists Test Deep-Rooted Soybeans to Fight Climate Stress and Store Carbon

In a field at the University of Illinois Urbana-Champaign, research scientist Ashish Rajurkar lifts a clump of soil wrapped around a soybean plant. Its roots run straight down rather than spreading sideways, the shape typical of most soybean varieties.

That downward growth is the focus of work at the Salk Institute for Biological Studies, which is investigating whether deeper root systems can help crops cope with climate extremes while pulling more carbon dioxide out of the air and holding it underground. Carbon dioxide from burning fossil fuels traps heat in the atmosphere and drives human-caused climate change.

Scientists have pursued other routes to remove atmospheric carbon, including direct air capture, altering ocean chemistry so seawater absorbs more, and reforestation. The Salk team is testing whether root systems can serve as an additional tool.

An $18 million grant from the Bezos Earth Fund will support field research on how well the plants tolerate drought and other climate stressors, how much carbon they can store and for how long, and how to bring them to farms at scale.

Wolfgang Busch, who directs the institute's Harnessing Plants Initiative, described the stakes as urgent. "We are actually steering in a direction that is very concerning," he said. "It will become harder to grow enough food for enough people."

Over six years, Salk researchers catalogued the genetic information of hundreds of versions of row crops such as soybeans and sorghum from around the world, building what research professor Todd Michael called an encyclopedia of plant genomes. After identifying 347 genes tied to carbon storage and root growth, they edited the plants' DNA to produce varieties whose roots push further into the soil.

"We wanted to leverage the natural variation of a given plant," Michael said. "We just have to be able to make the right crosses to bring in those genetics."

During droughts, the team hopes the roots will reach water below the topsoil while storing carbon deeper down, where tilling is less likely to release it. Researchers are also trying to increase carbon storage by encouraging larger root systems, leaving more carbon-rich material in the soil, and by raising levels of suberin, a cork-like, slow-decomposing substance in roots.

They hypothesize that steeper root systems may let farmers plant more crops in a smaller area, potentially lifting yields. Longer, bigger roots could also take up more nitrogen and other fertilizer runoff, which can trigger algae blooms and create low-oxygen zones that kill marine life.

Based on earlier laboratory results, Salk researchers estimate that one hectare (2.5 acres) of deeper- and bigger-rooted soybeans could store an extra metric ton of carbon dioxide per year. How long that carbon remains stored depends on root depth and soil conditions. Initial field results are expected this fall, Busch said.

At the Illinois site, Salk is growing deep-rooted soybeans under a canopy that opens and closes to control rainfall, simulating drought. Underground cameras and sensors let university partners track soil carbon and watch root growth in real time.

Uncertainty remains about how the plants will perform outside the lab. Data from Illinois and sites in Missouri, Kansas and Iowa are meant to yield accurate estimates of carbon storage and crop yield. Because most breeders have not focused on roots, "we don't really know what the real trade-off is," Busch said. "You have to test it in the field."

Busch acknowledged that new seed technology can be slow to reach farms. A crop with clear benefits for farmers and large seed companies is key to rapid adoption, he said, pointing to herbicide-resistant crops that spread in under a decade once introduced.

"Historically it's clear, if you have a technology that is interesting to a big seed company, it will go out there very, very fast," he said.

Widespread adoption would be needed for the carbon-reduction impact the institute envisions. A 2025 study Busch co-authored modeled that about a gigaton of carbon dioxide per year could be removed by 2040 if deeper-rooted soybean, corn, cotton and canola crops were adopted in countries where genetically modified crops are already grown. The study suggested adoption could be swift because the crops could be planted on existing farmland using current infrastructure.

Crop and seed development, however, takes years, and Busch said ambitious solutions need fast funding. "It's a race against time," he said of climate change. "We are racing against limiting the damage and crossing tipping points, where it's much harder to return from."