Rice husks, wood remains, nut shells, manure and
crop residues are regarded as agricultural waste, but
recently such solid wastes have been transformed
into biochar for the purpose of carbon sequestration.
Biochar is commonly defined as charred organic
matter, produced with the intent of being deliberately
added to soil to improve its agronomic properties. On
average, one ton of dry biomass can create 400 kg of
biochar containing 80 to 90% pure carbon