permaculture

[Lawrence London <lfljvenaura@gmail.com>]

There are more posts in this thread in the sanet-mg archives that this
forwarded post from me was included in.
There were replies with a lot more info on :
1) "determine how the different crop plants differentially select for
certain
species of VAM among all that are availible in the soil."
2) "that certain natural, plant-produced chemicals can
stimulate the existing VAM to higher levels of activity.  These
chemicals were originally derived from red clover"
[a group actually produced such extracts to make a marketable ag product
from]

I will find them and post them here.

<>

Article: 5512 of bionet.plants
From: niemirab@student.msu.edu  (Brendan A. Niemira)
Newsgroups: bionet.plants
Subject: Re: Mycorhizzae vs. Fertilizer
Date: Thu, 02 Mar 1995  11:04 est


For agronomic crops, you're talking about vesicular arbuscular
mycorrhizae (VAM), a symbiotic endomycorrhizal fungus.  These are
ubiquitous anyway, and
not very host-specific, so there is very little need to inoculate the field
in order
to introduce them.  The big trick is getting them to colonize your crop
plant to such an extent that fertilizer inputs can be reduced.  You can a)
build up the population in the soil such that even moderately active fungi
result in
heavy coloniazation, b) put something in the soil to stimulate the activity
of smaller populations to get heavy colonization.

Crop rotations have been shown to have a definite impact on the population
dynamics of VAM, and work is currently being done (by me, among others) to
determine how the different crop plants differentially select for certain
species of VAM among all that are availible in the soil.

Other workers have shown that certain natural, plant-produced chemicals can
stimulate the existing VAM to higher levels of activity.  These
chemicals were originally derived from red clover, a popular sequence in
crop
rotations.  This may shed some light on why rotations are effective
w/regard to VAM.