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["Lon J. Rombough" <lonrom@hevanet.com>]

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From: ARS News Service <NewsService@ars.usda.gov>
Reply-To: ARS News Service <NewsService@ars.usda.gov>
Date: Thu, 06 May 2004 11:49:55 -0400
To: ARS News subscriber <lonrom@hevanet.com>
Subject: Helping Beneficial Fungi Work

STORY LEAD:
Helping Beneficial Fungi Work

___________________________________________

ARS News Service
Agricultural Research Service, USDA
David Elstein, (301) 504-1654, delstein@ars.usda.gov
May 6, 2004
___________________________________________

Certain fertilizers can actually inhibit beneficial, naturally
occurring fungi that help plants use water and nutrients while
suppressing diseases, according to an Agricultural Research Service
scientist studying these beneficial root-dwelling fungi.

ARS plant pathologist Robert Linderman at the Horticultural Crops
Research Laboratory in Corvallis, Ore., is studying how these fungi,
called mycorrhizae, interact with fertilizers and other soil amendments
that have been commonly used in agriculture over the past half century.

Linderman is one of only a few scientists studying how mycorrhizae
affect the nutrition and health of nursery crops. He has measured the
level of mycorrhizal colonization of roots to see whether various
materials added to soil help or inhibit fungal growth. He studied a
range of commercial fertilizers and found that organic ones are usually
compatible with mycorrhizae, while phosphorus-rich inorganic fertilizers
usually inhibit them.

He also looked at peat moss, a popular additive to potting mixes used
to grow nursery crops. He found that in some cases it helps mycorrhizal
associations, while in others it hinders the fungi. Coir, a coconut
fiber that has become a popular potting mix additive, does not inhibit
mycorrhizae, but it may reduce growth of some plants.

Linderman is currently studying various types of composts to see what,
if any, effect they'll have on the establishment of mycorrhizae. His
initial finding is that some composts may suppress the fungi because of
high phosphorus levels.

After spending years researching these important fungi, Linderman
believes that he will now be able to advise growers as to which potting
mix additives will help establish mycorrhizae that can enhance plant
growth and health.    

Read more about this research in the May 2004 issue of Agricultural
Research magazine, available online at:
http://www.ars.usda.gov/is/AR/archive/may04/fungi0504.htm

ARS is the U.S. Department of Agriculture's chief scientific research
agency.

___________________________________________

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