Biochar Rediscovered
What if the world’s farmers introduced a simple, inexpensive and earth-friendly agricultural practice that could significantly reduce atmospheric carbon and slow the emissions of the more potent greenhouse gases methane and nitrous oxide? What if that practice produced enough energy to fuel itself, and as an added bonus produced a significant amount or carbon-negative energy in the form of biofuels?
What if it also increased soil fertility by retaining nutrients (while decreasing nutrient runoff, which pollutes natural waterways), built habitat for helpful soil microorganisms, and improved soil stability and tilth — even in some of the world’s poorest soils?
Finally, what if this practice were readily scalable and could be implemented by home gardeners and commercial farmers everywhere — spreading quickly to much of the earth’s arable land to form a giant atmospheric CO2 sequestering system?
In fact, this agricultural practice was introduced over 2,500 years ago by Amazonian peoples who created charcoal from vegetation by “burning” it in an oxygen-restricted environment (pyrolysis) — probably in pits covered with a thin layer of dirt that caused the vegetation to smolder rather than burn outright.
The prehistoric Amazonians then worked that charcoal into the famously poor local soil and added plant nutrients to it, creating arable plots of land called terra preta (black earth). In the 1960s, archeologists working in the Amazon Basin rediscovered these terra preta plots and slowly realized that their original purpose was to make agriculture possible in a region where crops could not grow without soil amendments.
Some terra preta fields that were abandoned at least 500 years ago (with the arrival Europeans in the Amazon basin) remain fertile to this day, proving that buried carbon persists in the soil. (Just as CO2 persists in the atmosphere, which must be “scrubbed” of excess CO2 if we are to slow or reverse global warming. Charcoal, which is close to pure carbon, is essentially inert, and won’t nourish plants, but it helps retain nutrients and supports microbial organisms.)
Research into the properties of terra preta and the benefits of using vegetation-based charcoal — now dubbed “biochar” — along with the pressing need to find solutions to the greenhouse gas problem, have spawned an international movement to promote the use of biochar in agriculture. The excellent web site of the International Biochar Initiative (IBI) serves as a primer in biochar applications and reports on home and industrial-scale biochar production facilities, agricultural research projects and conferences and events worldwide.

http://www.ecotecture.com/biochar-a-global...mazonian-earth/

http://www.biochar-international.org/