An ancient farming practice is getting a new life

MARY LOUISE KELLY, HOST:

Reducing emissions from farming will be key to meeting this country's climate goals. Agriculture is the fifth largest source of greenhouse gas emissions in the U.S. One climate-friendly growing technique called biochar involves literally burying carbon in the ground. And as Harvest Public Media's Kate Grumke reports, proponents say it's good for crops, too.

(SOUNDBITE OF BIOCHAR CRUNCHING)

KATE GRUMKE, BYLINE: Nick Cuchetti is mixing up something special in a bucket on his family farm in Luebbering, Mo.

NICK CUCHETTI: This is biochar.

GRUMKE: Biochar - it's a soil amendment, kind of like compost. And it's a super-hot topic in sustainable agriculture. It looks a lot like charcoal. Instead of burning the organic matter, it's cooked at a high temperature with almost no oxygen. As Cuchetti pours the biochar onto vegetable beds, you can hear what makes this substance special. It's extremely hollow and porous.

(SOUNDBITE OF BIOCHAR CRUNCHING)

GRUMKE: So why is Cuchetti so excited about this stuff?

CHUCHETTI: Pure carbon. You know, you put it in soil. It's just there. You can just forget about it. It's gone.

GRUMKE: Biochar is a direct way to sequester carbon dioxide, which is driving climate change. But there's a lot more to the climate-friendly practice. Biochar proponents say it creates a sustainable cycle of benefits on farms - recycling organic waste like cornstalks to make soil healthier and bury carbon. Isabel Lima first got interested in biochar more than 20 years ago.

ISABEL LIMA: We were trying to address the incredible amounts of waste that agriculture produces.

GRUMKE: Lima is a research chemist with the U.S. Department of Agriculture and sits on the board of a nonprofit that advocates for biochar. She says Indigenous people in the Americas have been using something like biochar for centuries. They would burn agricultural waste and put it back in the soil.

LIMA: And look very deep in the soil in the Amazon, for example, and we determined that those soils that we would otherwise expect to be very infertile are actually very fertile because of those practices.

GRUMKE: Now we know biochar makes a really friendly environment for microbes, which can be great for soil and help crops thrive. That's something Scott Booher has seen firsthand. He owns Four Winds Farm with his wife in Eastern Iowa. They grow organic hemp, flowers and herbs. When they first started farming their land in 2020, they had a soil test done.

SCOTT BOOHER: It was lacking in lots of different areas, so we spent a good bit of money on phosphorus, potassium, nitrogen.

GRUMKE: They also applied biochar. Since then, Booher hasn't had to add fertilizer again. He thinks that's because the biochar is holding onto nutrients. Research backs that theory. Less fertilizer is easier on the environment and cheaper. But Booher says the biochar cost benefit takes a while to show up.

BOOHER: If you're in it for the long haul, I think it's a great investment, but it is quite an expense upfront.

GRUMKE: Cost is one of the biggest hurdles to widespread use, says Myles Gray, program director at the U.S. Biochar Initiative.

MYLES GRAY: It's a relatively small industry. It's growing very quickly, and a lot of that growth is related to the carbon benefits of biochar.

GRUMKE: Gray says, thanks to the Inflation Reduction Act, there are new federal funds to incentivize climate-friendly farming practices, including biochar. But getting farmers into it is still a challenge.

(SOUNDBITE OF BELL RINGING)

GRUMKE: Back in Missouri, Cuchetti spreads more biochar out on his farm. He's especially excited that this is a long-term climate solution.

CHUCHETTI: And once you put it in the soil, it's permanent. You can't, like, go fish it back out.

GRUMKE: Experts say this carbon will be locked into the soil for generations.

For NPR News, I'm Kate Grumke in St. Louis.

(SOUNDBITE OF KACEY MUSGRAVES SONG, "OH WHAT A WORLD") Transcript provided by NPR, Copyright NPR.