With Rick Laing of Salt Spring Island Biochar
http://www.saltspringislandbiochar.com
Other helpful Biochar resources:
55 Uses of Biochar:
https://www.greenbelt.ie/sites/default/files/55_uses_of_biochar.pdf
Terra Preta by Ute Scheub:
https://greystonebooks.com/products/terra-preta