Is biochar the same as charcoal?
In this regard, can charcoal be used as biochar?
Theoritically, this should be possible considering that charcoal (solid/lump) and biochar (powder) are one and the same thing. The application (end use) and physical form are the reasons two different names exist for essentially the same material. So yes, it is possible to use it as biochar.
Keeping this in consideration, what can be used to make biochar?
Biochar can be made from a much broader range of materials than charcoal can. Crop residues, manures, and wood are all potential feedstocks. In addition to use in the soil, newer uses for biochar are now competing with traditional uses for activated carbon, carbon black, and graphite.
Worms like decomposing organic material to eat. Biochar doesn't decompose. In fact, what small pieces of biochar that actually pass through a worm's digestive tract wouldn't offer much to the worm by way of nutrition. But it would certainly charge the biochar with all sorts of wonderful enzymes and bacteria.