[Terrapreta] Black soil

[Richard Haard]

Thank you Philip - That is a worthy question to check out

On Jun 3, 2008, at 11:37 AM, Philip Small wrote:

> I do not have the reference at hand, but I have read that some soil  
> scientists are persuaded that, to a significant degree, the black  
> appearance of prairie soils is due to charcoal, and that 10 - 30% of  
> the organic-C in these soils is in the form of charcoal. My thought  
> is that it was probably a lower percent before tillage increased the  
> rate at which org-C evolves to CO2, (pre-Columbian was 5-15% of the  
> org-C maybe?) since char would be more persistent.