Carbon depletion from agricultural soils is one of the pressing issues of our time. The Ohio State Center for Carbon Sequestration estimates that 50-70% of the world's agricultural carbon has been off-gassed through tillage. As the fuel source for soil biology, the loss of soil carbon could have devastating influence on our food production for coming generations.
The San Juan Islands study examined the influence of biochar on the total carbon levels in soils, and found significant increases, with 35-45% increase for the biochar plots, and an additional 35-40% increase with the charged biochar.
Charcoal is a form of recalcitrant carbon, which means that it is very slow to decompose in soils. While recalcitrant carbon is not in a form for microorganisms to process, the physical structure of charcoal absorbs more plant available carbon, called labile carbon. As recalcitrant carbon, biochar is a form of carbon storage, keeping it out of the atmosphere. For every pound of biochar you put in the soil, you keep 2.93 pounds of carbon dioxide from the atmosphere. Let's put carbon in the soil, not the air.