[Terrapreta] carbon sequestration but where is TP?

[Brian Hans]

Sean et al,
   
  No that is not what I am refering to when I talk about lifecycle analysis, LCA. Eventho the complete data isnt there to show that char remains char for 1000's of years and that aspect needs to be documented, this isnt the subject of LCA. Washed char into the river-lake-ocean likely still remains char so erosion only means loss of place, not loss of sequestration. Again, someone needs to completely follow this 'bouncing char ball' from start to finish in a systematic way but this isnt the real issue of LCA. 
   
  The LCA that I am refering is the analysis on the complete cycle of char production when it comes to not only sequestering but also GHG remediation. http://en.wikipedia.org/wiki/Life_cycle_assessment
   
  Some question would be;
  What are the total emissions vs the total remediation of CO2?
  What are the complete emission constituants? 
  What is the emissions to move the char from where it now to eventually how it gets into the soil? If that takes tractors and heavy equipment...then CO2 remediation needs to be subtracted by the analysis. 
  What happens to the heavy oils and other 'stuff' that doesnt leave the char during charing process? 
  What is the construction pollution vs remediation lag time- if ever? (an example is a 'burn barrel'. Does the emissions that it takes to make the barrel, get the barrel to the lot and its lifespan exceed the amount of GHG's sequestered during the lifespan of the char making machine?)
   
  This list goes on and on. This LCA, once completed will THEN offer some terms for people like IPCC and others to consider char as remediation. 
   
  Dont get me wrong...Im not commention or making predictions to these 'Cradle to grave' aspects, Im just commention on what needs to be done to complete the LCA and offer the data to complete the answer to the questions that the IPCC is trying to offer answers to. 
   
  Brian Hans
   
  

"Sean K. Barry" <sean.barry at juno.com> wrote:
      v\:* {   BEHAVIOR: url (#default#vml)  }      v\:* {   BEHAVIOR: url (#default#vml)  }      v\:* {   BEHAVIOR: url (#default#vml)  }      Hi Brian, Edward,
   
  I am assuming that the Life Cycle Analysis of charcoal in soil that is being referred to here by you Brian, primarily relates to how long that carbon in the form of charcoal remains in the soil (and in that form)?  I believe that in past discussions on this point with you, Edward, you related that charcoal indeed has a very long, yet not infinite half-life in soil.  Something on the scale of several millennia, at least, if I recall.  You suggested, too, that this was a result of some research that has been done on this issue.  
   
  Additionally, it has been mentioned (by others on this list and in at least one Soil Science Conference, which I had attended in Philadelphia, PA) that some charcoal from Amazonian Dark Earths has been carbon dated at circa ~2500 years old.  I do not know specifically though where this carbon dating was done, by whom, or where it is documented.  I have been searching some for this, but have not found it in any literature on it yet.  Dr. Lehmann's book discusses Wim Somberg's finding that the ADE exists and was found in archaeological digs.  I have been trying to find the age of these discussed archaeological remnants but, again, have yet not seen any dates.  I think it is clear, though, that ADE is anthropological in formation and that the people who did this were at least Pre-Columbian, hence ADE is at least 500 years old.
   
  If a representative amount charcoal samples in ADE soils (let's say spanning the entire depth of several sites) is confirmed by calibrated carbon dating at ~500 to ~2500 years old since it was buried, then it seems to me that this would serve to support the premise that charcoal in soil does indeed have a long half-life, and it's Life Cycle is at least long lived.  This should be still true, even if it is not entirely understood as to how any decay of the amount of charcoal carbon occurs.  The decay would be a natural process.  If any sort of high speed loss events (like washouts or other large soil disturbances) could be discounted, then this decay should not show that charcoal exists for a long time, then just suddenly disappears from the soil horizon.  I think it would be gradual and would maybe have a long half-life, like other natural decay processes.
   
  Maybe what I am suggesting would be viewed as just speculation?   I do think, though, that any evidence of aged charcoal in soil can support a thesis of at least, a LONG Life Cycle of charcoal carbon in soil.  I should point out too, that here I am only discussing the longevity charcoal carbon containment in soil (C sequestration), not the Life Cycle of the fertility effects of ADE.
   
   
  Regards,
   
  SKB
   
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