the charcoal controversy as a soil amendment has boggled me for quite a while. arguments on both sides have been so convincing that i just stayed away from forming an opinion. my google-fu has been very strong of late and i believe that i can form an opinion and defend it. so here goes,
charcoal is very porous and it can afford places for the beneficial stuff to latch on. the little fungi and other microorganisms that help plants get nutrients like to live on porous stuff like zeolite and charcoal. it can also lighten the soil and make it retain water much better.
charcoal can absorb great amounts of nutrients which your plants might like to use. this is especially true when composting and many believe that charcoal and compost should never be mixed.
terra preta is portuguese for black earth. some time near the birth of christ the indigenous amazonian people were making a rich black soil. they a have basically been trying to reverse engineer the stuff and now believe that they understand it.
if i read this correctly then all i really need to do is "charge up" my charcoal with something very nutrient rich like urine or chicken manure tea. i am normally kinda scared of chicken manure compost since it easily burns plants. i then can add my "charged up" charcoal to my compost and get all the benefits of the charcoal without the deficits.
further reasons to use charcoal in this way is it sequesters carbon that breaks down fairly slowly. ideally i would create my charcoal in a low temperature situation but my wood stove is a great place to get charcoal since i already waste some when removing my ashes. ok, i realize that the small amount of carbon that i can sequester is infinitesimally small but at least i'm thinking about it..