[Terrapreta] Charcoal agriculture: not ready for prime time

[Tom Miles]

35 years ago in the national forestry development program in Mexico we
worked with intercropping and other techniques to restore tropical forest
soils that had been slashed and burned. It's interesting to think what might
have evolved if we had known about "slash and char". 

At that time one of the greatest deterrents to improving the soil was the
belief by rural smallholders that if they improved the soil someone would
take the land away from them. I don't know whether the technical and social
infrastructure, or the political will, exists today to promote slash and
char but it should be done.   

Tom    

-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of
rukurt at westnet.com.au
Sent: Tuesday, May 29, 2007 6:40 PM
To: terrapreta at bioenergylists.org
Subject: Re: [Terrapreta] Charcoal agriculture: not ready for prime time

Tom Miles wrote:
>
> My thought was more modest:  a concentration of charcoal left in a 
> poor soil from any natural cause could have resulted in abundant 
> growth and  inspired terra preta. Studies that I have linked on the 
> terra preta site have shown that the nutrient impact of fires in 
> grasslands only lasts for about a year, and slash and burn about three 
> years. Forest fires, however, can leave some substantial pockets of char.
>
>  
>
> Tom
>
>   
>
Nutrient impacts of fires are most likely due to the ash and not the 
charcoal, which is mainly left on the surface anyhow.
I believe that for maximum impact the char has to be ground somewhat and 
incorporated and possibly impregnated with other nutrients.

Kurt

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