Between 1824 and 1834 the Scottish naturalist David Douglas explored the major river routes of the Pacific Northwest. The following is an excerpt from his biography, The Collector, written by Jack Nisbet:
“Douglas, however, was much less alone in the wild than he imagined, and the owner of the plot soon caught up with him. Avoiding what could have been a serious affront—tobacco had a spiritual significance in many tribal rituals—Douglas whipped out his own manufactured strain as a peace offering and called upon his Chinook jargon to inquire about growing methods. The Kalapuya man accepted the gift, then described the tribal technique of searching out an open area in the woods with plenty of downed trees. They burned the deadfall, then planted tobacco seed in the ashes. Douglas, long a fan of “the good effects produced on vegetation by the use of carbon,” was well pleased. “When we smoked,” he concluded at the end of his account for plant #447, “we were all in all.”
Beneath the Brazilian landscape is a sandy-loam soil. Dusty to the touch, this soil has low fertility levels due to nutrients leaching out in the high Amazonian rainfall. One of the most fertile areas in the world, however, exists in these forests, known as Terra Preta de Indio, or Black Earth. Back in 2003 the Cornell professor Johannes Lehman published an article on these soils articulating extraordinary findings on their nutrient and water retention capacities. He posited that these benefits were in large part due to the high percentage of charcoal particles in the topsoil. Some of this charcoal dated back to the pre-Columbian Indian era 4,500 years ago, charcoal that he found still provided nutrient benefit today.
Several years after publishing his theory on "slash and char agriculture," Dr. Lehman published another study examining the amount of carbon dioxide that charcoal removes from the atmosphere. Dr. Lehmannposited that 10% charcoal application on the world's agricultural soils could sequester nearly the amount of humanity's annual greenhouse emissions.
Needless to say, Dr. Lehmann created a stir in the academic community. Could a fertilizer be the solution to climate change?
Lehman’s work catalyzed a series of studies on biochar throughout the major research universities internationally. A series of these studies found remarkable results: phosphorus and nitrogen were reduced by11% and 69% respectively, and calcium and magnesium by 77%. Another study illustrated charcoal’s water holding capacity, decreasing irrigation needs by 11%. In addition, charcoal amendments were found to serve as a food source for soil bacteria and a habitat for mycelium, aiding the natural nutrient cycling systems.
What also was uncovered is how many cultures used charcoal in agriculture throughout history: Greece. Rome, Hawaii, Jamaica, Dominica, basically every country in Latin America, Japan, and all throughout West Africa. Many of the countries are still actively producing charcoal today.
In addition, Dr. Darko Matovic at Queens University in Ontario published his own analysis of biochar’s CO2 sequestration, and found that it may be even more significant than Dr. Lehmann first thought. 10% charcoal application to the world’s agricultural soils, according to the mechanical engineering professor, would sequester more than the net 4.1 gigatons of excess CO2 humans add to the atmosphere each year.
But here’s the issue: researchers found that not all charcoal works the same. Some tests get significant results, some do not. Is this because of the type of wood used to make the charcoal, the way it’s made, the soil it’s put in, or the relationship between the three? No one knows.