'''Biochar''' is a name for [[charcoal]] when it is used for particular purposes, especially as a soil amendment.
Charcoal has many effects on soil fertility, although it is not much of a nutrient in itself. Some of the world's most productive soils (e.g. Canadian prairies, Russian [http://en.wikipedia.org/wiki/Chernozem Chernozem] / or "black earth") are very rich in organic carbon. This is now thought to be pyrogenic in origin, likely originating from prairie or forest fires. This carbon is often thousands of years old, demonstrating its stability in soil.