Stephen Machado reaches into a clear plastic Ziploc bag and pulls out the brittle but still intact remains of a pine branch collected from the Umatilla National Forest in Eastern Oregon. The blackened tree limb looks and feels and lot like charcoal.
In fact, that’s exactly what it is.
Woody debris from the forest is just another raw material for making what is known as biochar, which can also be made from organic material such as leaves, grasses, crop residue and even manure.
Machado, a professor and agronomist with the Oregon State University Extension Service, believes biochar has a huge upside potential for dryland farms in the arid Columbia Basin.
Working at the Columbia Basin Agricultural Research Center north of Pendleton, Ore., Machado stumbled onto biochar as part of his mission to make local wheat farms more sustainable.
Most growers in the area use a fallow rotation, meaning they grow a crop every other year and leave their fields fallow during the off years to build soil moisture. But Machado said that system has led to a steady decline in soil organic matter, which is the foundation of crop health and productivity.
“Organic matter is a source of nutrients for both the microbes and the crops,” Machado said.
Still, farmers are reluctant to give up fallow — especially in areas that get less than 10 inches of rain per year. With such little water available, they need every drop to grow enough wheat to pay the bills.
That is where biochar might be able to help. It contains up to 70 percent carbon, and its molecular structure is like a sponge for soaking up and holding water.
Machado began experimenting with biochar on small plots in 2012. Though he was initially skeptical, the results have shown a roughly 25 percent increase in wheat yields.
“I’ve been pleasantly surprised,” Machado said. “There is promise to this technology.”
Machado grew up in Gweru, Zimbabwe, in southern Africa. He remembers spending summer vacations at his grandfather’s farm outside the city, raising cattle and growing corn, peanuts and wheat.
At the time, Machado said he had no interest in farming — “Too much hard work,” he chuckles at himself in hindsight. Even then, he could see the soils deteriorate as they were depleted of nutrients.
“My grandfather was very poor, and could not afford fertilizer,” Machado said. “I could see, every year, the reduction in yields.”
Following Zimbabwe’s war for independence, Machado left the country as a refugee for nearby Swaziland. When the time came for college, he was given a choice between studying animal sciences or agriculture, two important skills that were needed back home.
Machado also played semi-professional soccer for Mbabane Swallows F.C. in Swaziland, and though they competed in packed stadiums, he said the players were not paid well. He decided to stay in school, eventually graduating with a bachelor’s degree in agriculture.
At the time, Machado said Zimbabwe was struggling economically, with 80-90 percent unemployment. Rather than return, he headed for the University of Reading in England, where he earned a master’s degree in crop physiology and agronomy.
From there, Machado arrived in the U.S., where he obtained a doctorate in crop sciences and agronomy from Kansas State University. He joined OSU in 2001, and applied for U.S. citizenship four years later.
Thinking back to the exhausted soils at his grandfather’s farm, Machado said the goal of his current research is to promote cultural sustainability without harming the environment.
“Farming is a business, and they’re looking at this year’s yield, but I want them to think about their children and their grandchildren,” Machado said. “If they’re gone, what are they leaving them with?”
Sustainability is the foundation of Machado’s interest in biochar.
The history of the substance dates back to prehistoric Amazonian tribes in South America. By burning vegetation and raking the charred leftovers into the soil, they could spend their entire lives growing crops in a single location within the dense rain forest.
European settlers came to know it as “terra preta,” or “black earth.”
“I was fascinated by the fact that these soils can remain productive for a thousand years without putting in anything,” Machado said.
Today, biochar is created through a process called pyrolysis, where biomass is burned at extremely high temperatures — up to 1,832 degrees Fahrenheit — with low levels of oxygen, avoiding combustion and leaving behind mostly carbon.
The material can be burned in pits, trenches, homemade kilns or larger, more sophisticated industrial equipment. By restricting oxygen, 50 to 70 percent of the carbon is retained in the solid biochar, while the rest is released as carbon dioxide.
But it’s the structure of biochar that makes it especially valuable to farmers.
Just one gram of biochar has a surface area of 1,000 square meters, Machado said. “It can hold onto everything.”
At the research station, Machado has several small plots of wheat and peas treated with biochar at different rates. His results show steady gains in crop yield for amounts of biochar ranging up to 5 tons per acre.
Another benefit, Machado said, is that biochar can mend acidic soils caused by ammonium nitrogen fertilizers, an issue increasingly seen among Eastern Oregon and Washington farms.
In his trials, soil pH increased from as low as 4.5, or highly acidic, to 6.5, which is closer to neutral. The critical pH level for growing wheat, Machado said, is 5.2.
“This is doing the job we need,” he said.
Gary Betts, who grows 260 acres of wheat near Athena, Ore., is working with Machado on biochar testing at his farm. The first year, Betts said they saw a 20 percent increase in yield on the experimental plots.
“You can dramatically reduce the use of fertilizer, maybe eliminate it completely, and it raises the pH,” Betts said. “It holds incredible promise of reducing agricultural costs, at the same time improving the environment for everyone in the area.”
The challenge is getting more farmers such as Betts to buy into biochar. Machado said the material is still quite expensive, up to 10 cents per pound, because not much is currently produced. That adds up to $1,000 for 5 tons, enough for about an acre.
Different types of biochar also have different properties, which makes it critical that farmers know exactly what they are getting.
“Because it’s a new technology, many farmers are not yet convinced,” Machado said. “And if farmers want it, it’s still a limited supply.”
Forest 2 Farm
Machado and Betts are part of a new nonprofit organization dedicated to making biochar more affordable, accessible and widespread.
Forest 2 Farm, established in June 2017, proposes using forest waste as a local feedstock for biochar, which would not only benefit farmers but provide a value-added market for otherwise unsellable wood.
Jim Archuleta, biomass and wood innovation coordinator for the Forest Service Region 6 in Portland, is working alongside the nonprofit. His interest in biochar traces back to his time working in the Diamond Lake Ranger District in the Umpqua National Forest of southwest Oregon, where applying charred material was shown to keep forage green into August, when other vegetation would turn brown.
The goal now is to create a market for biochar that can benefit farms, while also helping the forests harvest fine fuels that help spread increasingly large, destructive wildfires. Archuleta said their focus is branches less than 6 inches in diameter, slash and bark — material that would otherwise be burned in piles or left on the ground to rot.
“We can walk away from it, but at what cost?” Archuleta said. “If we’re able to figure out how to use this system strategically to create zones of reduced wildfire risk ... that’s what I hope this (project) can do.”
It takes 16 tons of raw material to make one ton of biochar, Archuleta said. At that rate, he figures the forests could make a serious dent in halting the rapid spread of wildfires by treating forests and converting the materials to biochar.
Archuleta also said the Forest Service is working with a private company to develop an in-woods mobile biochar processor capable of producing 10-20 cubic yards of biomass per hour. A beta version of the equipment could be placed in the Umatilla National Forest, near where Machado conducts his on-farm research.
Machado said the next step is to expand his trials to one or more acres to demonstrate the value of biochar on a larger scale.
Jerry Adams, secretary of Forest 2 Farm and executive director of the Evaluation and Development Institute, a climate-focused consulting group based in Houston, said they hope to secure funding through a combination of grants and public donations.
“It’s difficult to get farmers to change their practices based on small plots,” Adams said. “They want to look out over the horizon and see what’s changed.”
Adams believes biochar could sequester carbon dioxide in the ground and help stave off the effects of climate change.
Machado, meanwhile, is optimistic biochar could catch on in agricultural circles, if and when the market develops.
“Farmers are so good at transferring knowledge,” he said. “If it works on one farm, others will adopt it.”