Since the retort had issues, i looked for a way to get larger capacity and fewer parts to wear out. The idea: a pit lined with concrete blocks, which can be covered with a piece of sheet metal and soil.
It covers the basic carbon cycle, biochar's agricultural use, interaction with nutrients and microbes, reversing fossil fuel use, appropriate sources of renewable biomass.. my sources of information are, basically, this mailing list, and my own experiences making and using biochar.
