[Charcoal]

Low temperature woody charcoal (not grass or high cellulose) has an
interior layer of bio-oil condensates that microbes consume and is
equal to glucose in its effect on microbial growth (Christoph Steiner,
EACU 2004). High temp char loses this layer and does not promote soil
fertility very well.

The bio-oil condensates indeed favor some microbes and the oil can be utilized as easily degradable substrate. The combination of an easily degradable substrate with a recalcitrant substrate (charcoal) is interesting. I like a mixture of charcoal and chicken manure best! And mimics the adjectives of Terra Preta closest. These bio-oils are used in agriculture as pesticides, fertilizer mainly in Asia (Japan, China) and Brazil (Pirolenhoso). Providers of this product promise many advantages but research is needed to prove its suitability. Future developments will isolate certain effective compounds from the smoke. Today the bio-oils are called wood vinegar and the mixture consists of hundreds of different molecules (each source of biomass different) just as the charcoal is different. The future is bio- not petro-

... Evidence of terra preta's ability to
grow and sequester more carbon was undercovered by soil scientist
William Woods (U.Illinois). The work is still under investigation in
Brazil by over the last 20 years mining terra preta for potting soil
has not decreased its availability. Farmers have learned it recovers a
centimeter per year. The possibility those small fractions of char
continually migrate down, providing housing for microbes as they
process surface-cover biomass. The microbes and fungi live and die
inside the porous media increasing its carbon content.[/quote]

Well there are nutrient poor dark soils too. Organic matter can grow but nutrients not. Growing nutrient contents without external inputs would be alchemy. Charcoal can not "grow" and each mining of Terra Preta would delute the charcoal in the soil. For the tropics refractory soil organic matter is already a great deal and increases the soil?s ability to store nutrients, the water holing capacity among many other advantages. But this is not yet a ?Terra Preta?.