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Originally Posted by RBlack Thanks for the website. I didn't find anything there but did find that hardwoods make soils have a higher ph the softwoods (conifers) and an interesting fact that hardwood increased the CEC of soils but conifer actually decreased it. This from "Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal", Glaser, Lehmann, Zeck 2002
Thanks RB |
Glad to be of help.
You might find the "Terra preta" forum on Hypography of interest too
I am surprised about conifer char decreasing CEC
I think CEC is probably facilitated by bio-oils and resins in the wood.
These promote microbial and fungal activity in the soil and thus increase CEC.
(The type of soil clay/sand etc will also effect CEC. )
Charcoal needs to be made at low temps 4-500C to preserve these oil/resins.
Were both hardwood and pine chars made at the same temperature, and used in the same soils?
If not then a valid comparison can't be made.
Although there is suggestion in the research I have read that hardwood char is best for resins (at least in the tropics)