Mace is right, the mayans used to call that type of soil black gold, as the yield of grain crops grown on black gold soil would be double, this is one theory on how large populations would of been supported.
The charcoal within the soil holds on to the nutrients rather than leeching out the soil/....
fairly new product. The science was rediscovered by a Australian. It's bio-degradable matter, made into charcoal in a oxygen free environment. It's actually applicable as a power generation device since it's a carbon sink and generates power from the process. I would really love to own one of these machines!
You can buy th bags online, but very few outlet's that i have run across. I've yet to order any, though will soon.
I'm getting ready to try it. I've done research. Your best bet is to buy Cowboy Charcoal, 'cause it is all natural hardwood with no fillers found at your grocery; maybe..
The key is to make sure that you ground it up well.
Yields may increase by 20%. The scientists still are studying the potential yields; especially for "approved cash crops, such as CORN".
Do some more research and let us know what you find out. I'm excited about it!