Black Gold Biochar is an idea thousands of years old but one that seemed to have been (foolishly) lost by many along the way. Like charcoal, biochar is made by baking wood in the absence of oxygen and then quenched. It can then be ground down and worked into the soil to improve fertility and crop yields. It's believed to have been applied thousands of years ago in the Amazon, to generate the Terra Preta. Listen on the BBC: https://www.bbc.co.uk/programmes/m000z6x8