I'm missing ... mainly explained by mycorrhizal effects in the edaphone

Iris Cohen schreef
Sounds like a bunch of hooey.

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It may sound so but the existence of mycorrhiza has been well-proved. That
is not to say they are wellknown
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you can hear more of this from orchid friends, it's their primary focus

You are confused.
Iris

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Well, orchids don't start growing unless mycorrhiza are present
(or a nutrient solution mimicking them).
You can even assign orchids to taxonomic groups depending on the mycorrhiza
they favor.
PvR