Susanna Hecht's Powerpoint presentation on
Kayapo Soil Management shows how dark earth is made today. Very, very, very different from any method mooted in this forum. What you see is terra mulata formation rather than terra preta, but remember they have similar carbon contents and TP was probably made in a similar way but with mostly village refuse as input.
Remind me why we think a
different method based on charcoal production and soil tillage would also work, i.e. permanently sequester carbon and increase soil fertility. Perhaps we have made a jump from "It's got black carbon in it" to "They must have buried charcoal" without thinking too much about that.
M
