[Terrapreta] Scientific American Story on Charcoal Decomposition

['andrew']

On Wed, 14 May 2008 08:09:30 -0400, Lloyd Helferty wrote:

>How much extra carbon has been added to the soil by the addition of the C
>(char)?  

Since it was a hypothetical situation I was not giving a figure, I
wanted to first see what a typical scenario might be. The only
requirement would be that there were sufficient char added to cause
the observed effect of an increased respiration of som.



>IF it is more than 2 tonnes per ha per year then it is net
>positive, if not then we have produced a negative effect on soil carbon.  We
>can't forget the contribution of the char itself!

This is where I was hoping to lead the discussion, note that the
initial (stable) som is a consideration so if the effect is at all
linear then there is less sequestration benefit in using char on
highly organic soils, typically fenland soils in UK.

I don't know if it is at all realistic to just consider plough depth
as cereals often root far below this.

AJH