Biochar is incompletely burned biomass that is added to the soil as a soil =
amendment. The advantage of adding carbon to the soil as charcoal is that c=
harcoal has a half life in the soil of about a thousand years so the benefi=
cial effects of moisture retention and improved soil structure are long las=
ting and increase with every application. Much of soil in the Amazon basin =
appears to artificial and still benefiting from the pre-Columbian use of bi=
ochar.
I tried adding home-made biochar to my garden last spring but it will proba=
bly be a few years before I accumulate enough charcoal in the soil to be of=
much benefit.