soil
Biochar (aka Dark Earth)
American Indians have used it for centuries to create rich soil and grow better crops. Now its the newest 'discovery' of American academics. Its Biochar, the carbon rich end-product of the slow burning (pyrolysis) of organic matter, which can vastly improve soil for plants. When mixed with soil, biochar greatly increases water capacity, promotes the growth of soil life, and lasts for thousands of years.