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Optimizing a charcoal fertilizer
nChars were produced at 900, 600, 500, 450, and 400C.
nCrushed and sieved to #30 mesh, wt 20g.
nSoaked 5 min. in 48% NH4NO3 solution.
nEach rinse = 100 ml water 8.0 pH
Most stabilized after a few rinses
But at chars produced 400 C very gradually released its ammonia
 
We conducted leaching experiments on a variety of chars
This proved out true in our own tests. We experimented with several different charcoals to determine a charcoal with properties suitable for carrying plant nutrients. The difference in the lowest temperature char still surprised us.  Most of my charcoal samples would stabilize after the 5 or 6th rinses.  But the one produced at 400C was still slowly releasing ammonia after 12 rinses.