[Terrapreta] Chardb and characterisation

[Sean K. Barry]

Hi Rex,

ASTM 1762 - the "Proximate Analysis" test for Charcoal provides 4 types of information about charcoal samples: %moisture content, %volatile matter content, "%fixed Carbon" (%fC), and %ash.  It does not discern volatile matter composition or ash composition.  It DOES require a precision lab scale and some other lab equipment; grinder, muffle oven, muffle, furnace, crucibles, etc.  Along with things like, specified genus and species, maximum pyrolysis temperature, and residence time, I think charcoal can be fairly characterized in bulk.

Other information about charcoal-in-soil, I think, might better come from after it has been in soil that has been cropped (actually in-situ).  This would be observations about what effects there are on plants growing in the Teraa Preate soil under test.  This could be observations about the effects on the soil population of microorganisms, worms, and roots, etc. growing in the soil or things like SOM and CEC lab tests of the soil samples and maybe examinations of the plant weights, roots volumes, and leaf areas of the crops growing in TP soils, etc.

Regards,

SKB
  ----- Original Message ----- 
  From: Rex Manderson<mailto:Rexm at chaotech.com.au> 
  To: brauncch at gmail.com<mailto:brauncch at gmail.com> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Friday, April 18, 2008 11:50 PM
  Subject: [Terrapreta] Chardb and characterisation


  Christelle,

              I think that you will need to be encouraging further characterisation of the char to improve the value of comparison of results and methods.  The need for a quick test(s) was a key point to the Eprida presentation at the IAI conference in Australia last year.  There is not going to be much comparison between [ West Australian wheat trials ~35% C (IBI  "Improving wheat production with deep banded Oil Mallee charcoal in WA  30 Apr 07),  Wollongbar/Best Energies greenwaste biochar ~36% ( Australian Journal of Soil Research, 2007, 45, 629-634 ) ] and on the other hand [ CIAT  pots ~82% carbon  ( Biol Fertil Soils (2007) 43:699-708 )  or our own trials at ~80% carbon ( unpublished ) ].

   

  I understand that analytical chemical tests are not available to many who may wish to contribute.  My suggestion is that we start at least discussion to identify a priority in terms of characterisation of properties, and then publish some protocols for " kitchen laboratory" approximations.

   

  For our efforts we can have total carbon content analysis done by a nearby laboratory for less than $15 per sample, so this is a basic parameter.  Please consider adding it as a specific field, together with a method text qualifier.  Eg 79% Dumas method or 85% home test.

   

  After %C it gets a lot more complicated, and there has been discussion of CEC and other nutrient analysis.  While we have no experience yet, it seems the ASTM D 4607 "Standard Test Method for the Determination of Iodine Number of Activated Carbon" may be useful.  This standard warns "4.2 The presence of adsorbed volatiles, sulphur, and water extractables may affect the measured iodine number of an activated carbon".  It could be that for a high carbon char ( > 70% say ) that a larger iodine number = quicker positive soil cropping impact.  

   

  In a previous posting I asked about this test without result, so for this I will be more specific.  Have you been involved in testing char?  Was this ASTM method used?  Do you really need a balance accurate to +/- 0.0001g to do the test?   Any advice would be appreciated.

   

  I look forward to more test proposals.

   

  Regards

  Rex Manderson

  Chaotech Pty Ltd

   

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