[Terrapreta] Char application negative / delayed benefits

[Rex Manderson]

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.

 

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.

 

 

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.

 

Regards,

Rex Manderson

 

            

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