[Terrapreta] charcoal mix & long lasing effects

[Kevin Chisholm]

Dear Cristoph

Can we look at the problem through the other end of the telescope? 
Specifically:

Assume we start off with 100% charcoal, and wish to add soil to the 
charcoal. How much soil can we add to the charcoal, before growing 
performance starts to diminish?

What is the problem with "too much charcoal?" Is there a reduction in 
growing performance, or is it just that charcoal is being wasted?

Thanks!!

Kevin Chisholm

Christoph Steiner wrote:
> Hi,
> 30% charcoal in Terra Preta is definitely too high! The highest carbon
> values we found were around 10% which means that the charcoal
> concentration can not be higher. Dr. Bruno Glaser from the University of
> Bayreuth measured black carbon contents and found black carbon
> concentrations in the soil organic matter of up to 35%. Therefore
> estimations of a maximum of 3% charcoal are realistic and is still a huge
> amount of charcoal.
> Terra Preta is still exceptional fertile, but the creation date back at
> least 500 years.
> 
> Best,
> Christoph
> 
> 
> _______________________________________________
> Terrapreta mailing list
> Terrapreta at bioenergylists.org
> http://tech.groups.yahoo.com/group/biochar/
>