These farmers are cutting pollution and fighting hunger — with bacteria

By Nicolás Rivero January 1, 2026 The Washington Post

Mariangela Hungria won the 2025 World Food Prize for her work on microbes that feed plants nitrogen, allowing farmers to slash fertilizer costs and pollution.

Mariangela Hungria has spent four decades researching bacteria that convert nitrogen from the air into a form plants can use, boosting crop yields and reducing the need for expensive and polluting chemical fertilizers. (World Food Prize Foundation)

Mariangela Hungria knew she was on the verge of a scientific breakthrough that could transform Brazilian agriculture, fight hunger, slash pollution and keep struggling farmers out of bankruptcy. But, to get anyone to listen to her, she would first have to throw a great party.

Hungria is an agronomist who has spent her career studying how to use certain kinds of helpful bacteria to fertilize soybeans and other crops. Her research showed that instead of using pricey and polluting nitrogen fertilizers, farmers could spray their fields with microbes that have evolved over millions of years to pull nitrogen out of the air and fuel plants’ growth.

Today, 85 percent of Brazilian soybeans are grown using the bacteria fertilizers Hungria and her colleagues developed. Their work saves farmers about $25 billion on fertilizer costs and prevents 54 million cars’ worth of greenhouse gas emissions every year. Hungria was awarded the 2025 World Food Prize — the agriculture sector’s answer to the Nobel Prize — for her decades of work.

These so-called biologicals are commonly used to reduce chemical fertilizer dependence around the world. The techniques Hungria developed could boost their potency in other countries — including the United States — and supercharge soybean production in sub-Saharan Africa, where the crop is relatively new and millions suffer from hunger.

“There’s a really massive opportunity to replicate what Dr. Hungria has done,” said Manish Raizada, a professor in the Department of Plant Agriculture at the University of Guelph in Ontario, Canada. “If you solve this problem, you help solve global malnutrition.”

Recruiting farmers

When Hungria started her career in 1991 at the Soybean Center of the Brazilian Agricultural Research Corporation (Embrapa), few people believed in the promise of biologicals.

She had just finished a PhD in soil science from the Federal Rural University of Rio de Janeiro and postdoctorate research programs at Cornell University, the University of California at Davis and the University of Seville, where she studied biofertilizers. But she had trouble getting anyone to buy into her ideas at her new post in Londrina, a city in the center of Brazil’s southern soy-producing region.

“The use of biologicals in the soybean every year was zero,” Hungria said. “We had many soybean breeders that studied in the United States … and came to Brazil just talking about nitrogen fertilizers and chemicals, chemicals, chemicals.”

Hungria contacted an agronomist at the local soy farmers’ cooperative and asked if she could speak to the members about the benefits of biologicals. He was emphatic: “No. Nobody is interested. Nobody will go,” Hungria recalled him saying.

She insisted.

“Finally, when I called, I think, for the fifth time, he said, ‘Well, find somebody that will pay for a barbecue and beer, and then I can arrange for you to talk,’” Hungria said. This would become a common theme in her field work over the coming years.

“In Brazil, there is this tradition of throwing a party to talk about a product for the farmer,” she said. “The parties for the veterinary products, these are really wild. In our ones, it’s just barbecue and beer.”

Famers apply bacteria to millions of acres of soy and corn fields like these in the countryside of Tocantins state, Brazil. (Rafael Vilela/For The Washington Post)

At that first party, Hungria spoke to hundreds of soy farmers who worked small plots in the region. By the end, she said, the crowd applauded and the agronomist apologized for blowing her off. “From there, we did some tours all over Brazil,” she said.

Hungria and her colleagues met thousands of farmers, working alongside them to test and identify promising techniques that worked best on their fields across Brazil’s varied soils and climates. She prioritized speaking to people who disagreed with her and converted them to the use of biofertilizers with evangelical zeal.

“If I have two invitations, and one is from a very nice forum with nice people that I know believe in nitrogen-fixing biologicals, and the other one is with very nasty people that devastate forests and like all the chemicals, I go to the [second] one,” she explained.

Just as much as her scientific rigor in the lab, her commitment to working with farmers in the field cemented her success, according to Tom Vilsack, a former U.S. agriculture secretary and CEO of the World Food Prize Foundation.

“She won this award through the force of personality and energy and commitment,” Vilsack said. “She just beat the bushes.”

Recruiting microbes

In their native East Asian soil, soybeans developed a special relationship with an ancient group of bacteria called rhizobia.

Rhizobia excel at pulling nitrogen out of the atmosphere — where it makes up 78 percent of the air we breathe — and chemically transforming it into a form plants can use. Soy plants’ roots are full of nodules that form a perfect habitat for rhizobia, with low oxygen and a steady supply of sugar that the plant swaps with the bacteria in exchange for nitrogen.

When farmers started growing soybeans in other countries that didn’t have native rhizobia in their soil, they had to replace the nitrogen the bacteria naturally gathered with synthetic substitutes.

Today, nitrogen fertilizer for all crops generates 2 percent of global greenhouse gases, on par with the airline industry. Roughly half the fertilizer that farmers apply to their fields gets wasted: Some washes away, polluting waterways and fueling toxic algae blooms, and some gets converted into nitrous oxide, a greenhouse gas nearly 300 times more powerful than carbon dioxide.

“It sustains the world population,” said Mari Winkler, a professor in the Civil and Environmental Engineering Department at the University of Washington. “So, while it’s good that we can all now have food, there are all these environmental consequences that come with it.”

Introducing the right strains of rhizobia into the soil can help soybean crops and bacteria team up to fix nitrogen on their own, reducing the need for chemical fertilizers. Farmers in the U.S. and Europe started doing that in a widespread way by the 1980s, but in the early ’90s, it hadn’t caught on in Brazil.

Hungria received the 2025 World Food Prize for her research on biological nitrogen fixation, which transformed Brazilian agriculture and could be applied around the world. (World Food Prize Foundation)

Hungria and her team identified bacteria strains suited for Brazilian soils and then went a step further, finding that reapplying biofertilizers each growing season could boost soybean yields 8 percent higher than what chemical fertilizers could achieve.

They also recruited another biological ally — bacteria strains from the genus Azospirillum — that fixes nitrogen and helps plants grow bigger root systems, allowing them to pull nutrients out of the soil more effectively. Even if a farmer still uses chemical fertilizers, these bacteria help the crops absorb the nutrients more efficiently.

Using both rhizobia and Azospirillum together boosted soy farmers’ profits more than $45 an acre each season over a five-year study on 3,000 farms. Other crops, such as corn, wheat and rice, lack root nodules that host rhizobia, but they can benefit from the Azospirillum treatments Hungria and her team developed. Brazilian farmers use these biologicals on 19 million acres of corn and a growing share of wheat and rice. Visit The Washington Post for the original article.