Productive Carbon Sequestration

Terra Preta is interesting stuff. As a soil it is highly productive. Pre-European Amazon civilization flourished in an area with notoriously poor soil because of it. Research has shown that not only is it productive, it actually can gradually sequester more carbon from the surrounding organic material and become more and more productive. It entices one to start building one's own garden with it. And extending the thought, what would the impact be if large agricultural operations began to use it?