What is biochar and how can it influence C sequestration?

This is a short document about biochar and its climate-smart benefits. Biochar is charcoal produced through pyrolysis, where organic matter is heated with limited or no oxygen. Two by-products can be used as bio-fuel (bio-oil and gas). The quantity of carbon (C) in the biochar depends on the type of feedstock used. For example, the woody feedstock will deliver a higher carbon biochar than the herbaceous feedstock. The quality obtained depends on the organic matter type and pyrolysis temperature. The critical factors determining the quality are the adsorption (the process by which molecules (such as gases, liquids, or dissolved substances) adhere to the surface of a solid or liquid), the cation exchange capacity (the ability of soil or other materials to hold and exchange cations (positively charged ions, such as calcium (Ca²⁺), potassium (K⁺), or magnesium (Mg²⁺))., and the low levels of mobile matter (tars, resin, and other short-lived compounds). Converting biomass C to biochar results in the storage of 50% of the initial C, compared to only 3% of the C remaining after burning and 10 to 20% of C sequestered after biological decomposition.