[Stoves] Terra preta. was Re: [Fwd: Re: Stoves in China]

[frank]

Dear Paul, Jeff and stovers,

I agree that compost is only good for a year or two and char will help 
improve the texture of poor soils and last for a long time. Char will 
also contain a small amount of nutrients (compared to compost).  It just 
seems so much went into producing the char and it is so energy dense its 
value is better used elsewhere. So its just weighing the benefits  and 
choosing the use.

Frank




Paul S. Anderson wrote:

>
> Quoting frank <frank at compostlab.com>:
>
>> Stovers
>> I suggest there may be much better use for charcoal than returning it to
>> the forest. It does contain some nutrients like potassium, phosphorus,
>> calcium etc but there are better ways to add these (compost) and it may
>> help improve the structure of a poor soil. I don't see the carbon being
>> available to the plants as I have found it in thousand year old
>> archeology sites.
>
>
> Frank, the carbon (char) in terra preta old soils is not to go into 
> the plants,
> but to help the soil be better for the plants.  Carbon in compost with 
> be lost,
> but the char is a nearly permanent improvement.  Especially in the humid
> tropics, the compost (incl leaf litter) is rapidly decomposed and/or 
> leached.
>
> I suspect that the nutrients (P, K, Ca, etc) in the ash do become 
> available to
> the plants.
>
> This is especially for tropical soils.  And maybe mid-latitude sandy 
> soils??  Nothing against composting.  But char into the weak soils is 
> ANOTHER way of
> improving soils, especially in the tropics.
>
> Paul
>
>
>
> I would think mixing it in with small fuel that is
>
>> densified may be a better use.
>> Frank
>>
>> Jeff Davis wrote:
>>
>>> Crispin wrote:
>>>
>>>
>>>> As is obvious, if a person goes back into the forest to cut more wood,
>>>> then there is a problem.
>>>>
>>>>
>>>
>>>
>>>
>>>> If I have a gasifier that requires 2 kg of wood each day, making 1 
>>>> kg of
>>>> charcoal is not helping the forest re-grow.
>>>>
>>>>
>>>
>>> The theory is that one would return the charcoal back to the forest.
>>>
>>> As a side note; truckers have a term for finding something to haul 
>>> on the
>>> empty leg of their trip but the term escapes me at present.
>>>
>>>
>>> Jeff
>>>
>>>
>>>
>>>
>>>
>>>
>>
>> -- 
>> Frank Shields
>> Soil Control Lab
>> 42 Hangar way
>> Watsonville, CA  95076
>> (831) 724-5422 tel
>> (831) 724-3188 fax
>> frank at compostlab.com
>> www.compostlab.com
>>
>>
>>
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>>
>
>
>
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>
>

-- 
Frank Shields
Soil Control Lab
42 Hangar way
Watsonville, CA  95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com