Germany is still a laggard when it comes to the approval of biochar. Currently, it is only permitted in the form of charcoal with a carbon content of at least 80 percent. Technology has been available for a long time to produce biochar free of harmful substances. Quite the opposite of barbecue coal purchased from the DIY store, which far exceeds the limit values for carcinogenic substances.
Original article (German): Pflanzenkohle als Düngemittel (Biochar as fertilizer)
Author: Rebecca Hillauer
Published in: Deutschlandfunk 2015