Research on fire ecology led Tom DeLuca to investigate charcoal’s potential role in agricultural soils. This research took him to Wales, where basket weavers historically used charcoal to enhance growth rates in their willow trees. Later he studied the relationship of charcoal with nitrogen fixing legumes and cover crops. Through these 20 years of research he’s developed several key theories.

The first is that charcoal works most effectively in disturbed soils or sandy soils, building up nutrients and the micro-organism populations. This soil description fits basically every urban soil in the world.

The second is that charcoal should be made and used locally. Because it evolved through forest fires, where a tree becomes charcoal and drops to the ground directly below, this charcoal will be best designed for that soil’s nutrients, structure, and biology. While we are not going to start farming in forests, we should attempt to produce and amend charcoal as locally as possible.

Third, biochar makes the most sense as part of waste management systems, both rural and urban. For example, Orcas Island—made up of only 50 square miles—produces 300 tons of slash material annually from the local logging industry. The majority of this material is currently being burned in brush piles.

Lastly, the real benefit of charcoal is time. DeLuca discussed the Terra Preta studies, with some of the charcoal dating back 4,500 years ago, charcoal that is still providing nutrient benefit today. It actually may be providing more now than when it was first created. At this point in the conversation Tom paused and looked out the window although it was night. “We’re still not sure why, but charcoal seems to increase humus production more and more the longer it’s in soil.”

Humus, not to be confused with the delicious Mediterranean chickpea dish, is what all farmers are looking for. It’s what bonds with fertilizers and holds nutrients in the soil. If you’ve ever put your hands into soil that feels almost silky to the touch, that smells like molasses, humus is the reason.




“That’s the problem with biochar, there are so many variables,” Dr. David Granastein told me. Dr. Granastein is a soil and agricultural biologist at Washington State University. Like Dr. DeLuca, he believes that charcoal’s effectiveness changes depending on the wood, production method, and soil type. Dr. Granastein, like so many researchers, feels there is a need for more localized research before we can make too many claims on biochar. While he agrees the potential is significant, he’s not ready to proclaim its benefits.

While there is a need for more research, Dr. DeLuca feels there is a need to join the existing research in the field. After investigating, and conversing with his colleague Dr. Lehman at Cornell, Tom has concluded that there has not been a significant aggregation project of biochar research. Currently studies are published in isolation in academic journals. Without merging the results of existing work, no one knows the extent of variability in charcoal effectiveness, or what directly leads to this variability. For example, is the wood type more important than the production method in determining effectiveness? Right now, we don’t know.




There’s a good reason why an aggregation project hasn’t occurred: not everyone is asking the same questions. Data systems depend on standardization. Even though many researchers are examining the same topics, the way they track the question can differ.

What we miss in this are trends. What is the production method that provides the greatest nutrient benefit across a region or country? We don’t know. Are there types of charcoal that wok better for retaining water and lowering irrigation use? We don’t know. What’s the most economical method for producing the highest quality charcoal by locality? We don’t know.

Because we don’t know the answer to these questions, there isn’t a market. It’s difficult to go to a farmer and tell them to buy a product because it’s been used throughout history. If we can’t tell them what it offers their soil and how it’s going to lower their costs, they won’t buy it. If farmers are making -$1,682 per year, they sure can’t afford to take risks.

If there isn’t a market, people don’t make it, and it stays an area of research consolidated to the labs of our universities and the pages of academic journals.

Joseph Heller might have called this a catch-22, but we call it a data problem.