Biochar is a fine-grained charcoal high in organic carbon and largely
resistant to decomposition. It is produced from pyrolysis of plant and
waste feedstocks. As a soil amendment, biochar creates a recalcitrant
soil carbon pool that is carbon-negative, serving as a net withdrawal of
atmospheric carbon dioxide stored in highly recalcitrant soil carbon
stocks. The enhanced nutrient retention capacity of biochar-amended soil
not only reduces the total fertilizer requirements but also the climate
and environmental impact of croplands. Char-amended soils have shown 50
- 80 percent reductions in nitrous oxide emissions and reduced runoff of
phosphorus into surface waters and leaching of nitrogen into
groundwater. As a soil amendment, biochar significantly increases the
efficiency of and reduces the need for traditional chemical fertilizers,
while greatly enhancing crop yields. Renewable oils and gases
co-produced in the pyrolysis process can be used as fuel or fuel
feedstocks. Biochar thus offers promise for its soil productivity and
climate benefits."
"Biochar enthusiasts generally agree that raw biochar needs to be
processed further prior to being added to the garden. Composting, or
soaking with compost tea, is commonly used to charge the pore volume
with beneficial organisms and nutrients. Soaking in a nutrient rich
solution (examples are urine or fish emulsion) prior to composting is
accepted practice."
Activated carbon, also called activated charcoal or " Activated coal" is
a form of carbon that has been processed to make it extremely porous and
thus to have a very large surface area available for adsorption or
chemical reactions.[1]
The word activated in the name is sometimes replaced with active. Due to
its high degree of microporosity, just one gram of activated carbon has
a surface area in excess of 500 m2, as determined typically by nitrogen
gas adsorption. Sufficient activation for useful applications may come
solely from the high surface area, though further chemical treatment
often enhances the adsorbing properties of the material. Activated
carbon is usually derived from charcoal.
[permaculture] Gardening with Biochar FAQ / FrontPage & active charcoal,
Lawrence F. London, Jr., 01/07/2010