On farms in Texas and Mississippi, this giant mobile device is helping to fight climate change

Last fall, on the family’s 1,000-acre farm in Texas, a tractor drove through a cornfield pulling a container-sized machine behind it. In the past, a mechanical harvester picked up corn stalks and other agricultural waste left after the last harvest, and cut them into small pieces. Then the plant material went into a machine in the back, where it was heated to 1,472 degrees Fahrenheit—and turned into biochar, a charcoal-like substance that can help fight climate change.

Applied Carbon, an equipment startup, announced today that it has raised $21.5 million in Series A funding to deploy its fleet of biochar equipment in states including Oklahoma, Arkansas, and Louisiana.

When plant waste sits in the field and decomposes, it releases greenhouse gases. But when plants are converted into biochar, the carbon taken up by the plants as they grow is locked away in the environment. Biochar can be added to fields to improve soil health and increase crop yields.

“When we convert biomass into biochar, we are thermally converting the carbon from a rapidly decomposing form into a stable, mineral form of carbon,” said Jason Aramburu, founder and CEO of Applied Carbon. “This carbon mineral takes a long time to break down in the soil—anywhere from hundreds to nearly millions of years depending on the quality of your process. On average, we can absorb billions of tons of CO2 every year in the form of biochar. “

Biochar has a long history: In parts of the Amazon Basin, it has been added to soil to fertilize it for over 2,000 years. But the traditional way of doing it—burning piles of wood covered to limit oxygen—releases a lot of CO2. The carbon machine used, a “pyrolyzer,” dries and burns the biomass inside a closed, low-oxygen chamber, creating both biochar and gas that is used to run the process. The conversion takes about two minutes.

Currently, most biochar is made from wood waste in power plants near the coast. “This method of producing biochar is problematic because it is very expensive—wood has many other commercial uses,” said Aramburu. “And it requires transporting tons and tons of material hundreds or thousands of miles to the farms in the heartland.” Because it is difficult to move, biochar is usually only used on high-value crops such as organic vegetables or wine grapes.

There is also not enough waste to cause significant damage to the climate challenge, he says. The company realized that using agricultural waste, such as cornstalks or wheat straw, would be a better source. But that biomass could not be processed easily with existing machines. “We had to re-invent the pyrolyzer to convert these things properly,” he said. Collecting it from the fields to a central location was also a challenge, so the team designed a mobile device that could go to the field instead. The biochar created can be used by the same farm.

For farmers, it means better performance: Studies show that biochar can increase crop yields by 16%. It also increases the microbial activity in the soil, which means it is healthier. Farmers can use less fertilizer and less water.

Over the past two seasons, Applied Carbon has conducted trials with farmers growing corn, cotton, and peanuts in Texas, Arkansas, and Mississippi, testing how its method compares to similar untreated acres on the same farm. Crop yields, soil chemistry, and water retention improved as expected, said Aramburu. Farmers pay per hectare based on the expected yield increase and what they can use to plant agricultural waste. (The company has not shared costs.) In some cases, state and federal funding is available. The startup also sells carbon credits for its carbon offset service.

If biochar were used in row crops around the world, said Aramburu, research suggests it could remove up to 2 billion metric tons of CO2 each year. “I believe this may be an underestimation, as it does not consider a production system like ours, which can harvest and open up new sources of stock that were traditionally inaccessible or unprofitable,” he said.