This is the bit about plant/carbon resins.
Is this why activated carbon would be no good?
Could it have some use?
(If not, pitty, as I've just found a source for it "Barmac" seels "Pickup" for greenkeepers to use on grass. It is so fine it can be sprayed on in a water slurry)
"How does this work?
What the soil scientists, working with microbiologists, discovered was that a community of bacteria exists in symbiosis with the root hairs of plants. The bacteria produce enzymes that release the mineral ions trapped by the heat stabilized plant
resins
in the charcoal and make it available to the root hairs of the plant as nutrients. In return, the plants secrete nourishment for the bacteria. Not only that, but the resins within the charcoal act like an ion exchange resin, adsorbing traces of mineral ions onto the charcoal particle surfaces from the rain water, and trapping it within the charcoal's molecular structure, where it can be held for centuries - until the soil bacteria associated with a root hair come along and secrete the enzymes necessary for it to be released once again. So the trace minerals always present in rainwater actually act as a fertilizer - providing the nutrients needed by the crops, year after year. The secret of the soil fertility of the terra preta was finally understood"
and also:
"Bio-char seems to have another interesting property: it seems to "stimulate" AMF.
The idea that the application of charcoal stimulates indigenous arbuscular mycorrhizal fungi (AMF) in soil and thus promotes plant growth is relatively well-known in Japan, "
Both quotes from an excellent article (that even tries (but fails) to explain the hydrogen story/link to me)
it is a great article I recommend it to you
http://www.garyjones.org/mt/archives/000273.html