photo - Charcoal Green
Biochar is a name for charcoal used for agricultural purposes as a soil amendment. It is on the long and growing list of sub-irrigated planter (SIP) media ingredients to test in the upcoming growing season.
To ensure its quality for test purposes, it will be purchased from a commercial source rather than burned in a backyard.
Improving the quality of the soil media, while lowering the cost, is one of the top prorities of SIP agriculture.
Update: Read Akbar's comment from Indonesia. It is most informative, since we are not likely to get much help from our horticultural institutions who are essentially mute on the subject of SIP growing.
ScienceDaily (Mar. 22, 2012) — Backyard gardeners who make their own charcoal soil additives, or biochar, should take care to heat their charcoal to at least 450 degrees Celsius to ensure that water and nutrients get to their plants, according to a new study by Rice University scientists. Read more...