Biochar

Biochar is the lightweight black residue, made of carbon and ashes, remaining after the pyrolysis of biomass, and is a form of charcoal. Biochar is defined by the International Biochar Initiative as "the solid material obtained from the thermochemical conversion of biomass in an oxygen-limited environment".[1] Biochar is a stable solid that is rich in pyrogenic carbon and can endure in soil for thousands of years.