[Terrapreta] Char application negative / delayed benefits

[Greg and April]

Interspaced in Blue.

  ----- Original Message ----- 
  From: Rex Manderson 
  To: terrapreta at bioenergylists.org 
  Sent: Wednesday, June 04, 2008 20:18
  Subject: [Terrapreta] Char application negative / delayed benefits


  Hello all - please find below a couple of delayed responses to earlier posts.

   

    1.. following from Michael Bailes on 1st June.  I am reluctant to talk about negative effects of char application, but can identify two circumstances where the outcomes were initially negative,  In a small pot trial we conducted with radish and "poor" soil the char amended pots with no added nutrient were 32% less biomass than the control soil sample.  In contrast the char + nutrient pots were 42% more than the soil + nutrient counterpart. ( hoop pine sawdust char peak 450deg 80% carbon ) 
  Rank Table:  Soil + Char   68% mass

                    Soil control   100%

                    Soil + fertilizer 138%

        Soil + char + fertilizer  196%   ( expressed as 196/138= 1.42 for 42% )

  From this we concluded simply that if there is not enough nutrient to satisfy all the life in the pot, then the microflora will win the race for the available nutrient.

   

  I have also had discussion with some other experimenters who admitted to knowledge of negative results, which may have come from the presence of a large amount of unconverted material since the char in question had a low carbon content.

   

  In summary lousy soil or lousy char can both result in nothing gained.



   

  This is not totally new.    



  Composters have known for some time that poor results occur if the compost is not completely finished as the microorganisms directly compete with plants for nutrients.    



  I'm actually not surprised that something similar is occurring with char and soil that doesn't have extra nutrients.





  2.  following from Greg H on 5th June

  "and then trying to convince farmers to spend the money on something that is not going to return any benefits for at least the first couple of years.

   

  Greg H."

   

  In that same pot trial the char was added the day of planting and the radish harvested 30 days later.  There was absolutely no waiting for the benefit to be realized!   I can imagine circumstances of application where the results do not appear for some time, and could probably find references for published work with this profile.  However this is not a proof that delay in benefit is an inevitable part of the char process.  We just need to use good stuff with appropriate attention to the condition of the soil to get an immediate gain.



  Let's me ask you this, how long would it take a farmer to reach the same char level in his fields, as was in your pot's?    If what I hear is correct, then we can expect that he would need to obtain at a very minimum a level of 6% char in the top 6 inches of soil.    



  If my math is correct, even if he only owns 100 acres, he still has to have over 234,000,000 ( that's right, 234 Million ), cubic yards of char to achieve that level ( assuming .4 inches of char in the first 6 inches of soil ).    How long is it going to take him to acquire all this char?



  This is what I was talking about.    Now I don't doubt that the farmer can do a portion of his fields one year and another portion of his fields another year ( and so on ), and see fairly quick results in just those parts of the fields that he has applied char to ( assuming that his fields are not nutrient poor ), but for the time and money he is putting into the char, he is seeing only a fractional increase, until the majority of his fields are covered - which will probably take a few years ---- does my comment now make a little more sense?  

   

   

  If anyone wonders why this little 10 pot trial is not in some data base or published, I have to say that without some attempt to characterise the char and the soil it is all just a collection of anecdotes.

   

  I hope to be able to provide more useful data in future, but we have had our next set of pot trials on hold since January because I have not invested the time to find a source for a reasonable fertiliser application schedule to use in the series.  We do not appear to have attracted too many commercial farmers to this list, and perhaps that is something that some contributors should take as an indication of poor input.



  It might help if we knew just how much char was needed to make a difference, then estimates can be raised or lowered as needed for any real improvement in crop production.





  Greg H. 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080605/1e26a216/attachment.html