[Terrapreta] Using Biochar to Reduce N and P Use or Runoff

[Tom Miles]

Richard,

 

Thanks for your thoughts and comments. 

 

1.       Are you referring to a prepared biochar product with nutrients like
EPRIDA offers?

2.       This would be addition of biochar to create a microbial nutrient
sink for N and P

3.       Are there existing bio-fertilizers that do this?  

 

By using chemical fractionation we have found P to be highly soluble in
straws and shells and less soluble in woody wastes. We found that burning
poultry litter  (at 800C) reduced the solubility of the P (as P205) to 0.2%
water soluble and 13.3% citrate soluble. That would reduce leaching but also
reduce availability to plants. We had to treat it to increase its
solubility(to 27% and 11% respectively) and use as a granulated fertilizer
product. http://www.fppcinc.org/pdf/capefear.pdf

 

I don't know how well availability of P is documented for pyrolysis char.
Pyrolyzing P (at 500C) into a fixed carbon matrix (char) probably results in
a higher proportion of soluble P. If it is trapped in a the matrix it may be
less mobile in rainfall. Eventually it might be chelated, or sequestered by
microorganisms. We need data. 

 

Thanks

 

Tom

 

 

 

Some thoughts on this topic - So far two methods of N and P runoff have been
mentioned. 

 

1. Introduction of N and P sequestered in biochar and thereby controlled
release

2. Control somehow in the soil by charcoal of N and P movement by cation
exchange and via micobial habitat sequestering as biomass.

3 A third is reduction of fertilizer needed by way of enhancement of
chemautotrophic organisms  for nitrogen fixation and mycorrhizial organism
enhancement to convert insoluble phosphorus into a plant available form with
direct transfer into crop root zone.

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