Re: Re: gardenwriters Digest, Vol 2, Issue 1

**"Doreen Howard" d*@ticon.net**

Lee Reich wrote:

> Do you have any references indicating that mycorrhizae aid in N nutrition?

I'm referring to the rhizobium-mycorrhizae association.  In poor soils,
legumes can build nitrogen for other crops such as maize.  But, the
rhizobium that forms on legume roots and manufactures nitrogen needs
phosphorous.  Mycorrhizae mines and supplies the element.  There are
numerous studies and anecdotal information about this association.

> Also, I believe that large amounts of P do not kill the fungi, but merely
> suppress the development of mycorrhizae. Perhaps the plant chooses the
easiest
> route: using fertilizer P takes less energy than using P garnered by
> mycorrhizae.
You could be right here, but the fungi are gone in either scenaro.  And,
there is no glomalin produced, phosphorous mined, water supplied,
antibiotics produced and all the other good stuff the fungi do.

 After all, the fungi need to be fed, too, and use some of the
> carbohydrates manufactured by the plants.
But, they channel more to the plant than what they take--including nitrogen.
The plant takes at least 60 percent of what the mycorrhizae mine.

Also, soil temperature has lots to do with mycorrhizae and its performance.
Someone mentioned not seeing it in compost piles.  When soil is above 95F or
so, the fungi form spores and are not active.  Many are weakened and
destroyed when the hot soil is also steamy, like in an actively cooking
compost pile.  In the South, soil solarization is common to kill pathogens.
It also kills mycorrhizae.
Doreen Howard

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