Re: Fungi and soil (Was Re: [compost_tea] Sulfur)

From: <soilfoodweb_at_aol.com>
Date: Sat, 03 Jan 2004 18:29:23 -0500

Grains are not added for the purpose of inoculating species of fungi. Fungal diversity in dried, milled grain materials is not really worth worrying about.

Not all grains work really well. Through trial and error, several materials have been singled out, since they often give good growth of the fungi that are present in the compost.
Oatmeal, feathermeal, soybean meal, etc are foods to grow the fungi.

The term, mold, is another name commonly applied to fungi. Many people think molds are the bad guys, while fungi are the good guys. The term is used that way in some scientific literature, but it is not actually generally accepted as having any validity.

White molds can include beneficial fungi that decompose plant cellulose and cell wall structures. Some white "molds" are pathogens, since they can attack plant cellulose and cell walls while the plant is still alive. Kind of a problem there, but the fungus doesn't really MEAN to cause any trouble. It just didn't know that the plant wasn't quite done with the material......

Many people mean mildew when they say mold, but what they really mean is mildew. The term mold get applied to the fuzzy stuff that grows on your bread in the refrigerator (typically Penicillium or Rhizopus), or on oranges or other citrus products, again Penicillium is common (different species from the bread attacker), or Trichoderma, or a herd of brown guys, or little white guys (which we call LWG's).

We mean fungi when we talk about filamentous, non-photosynthetic eucaryotes. Some fungi have the enzymatic capacity to break down really nasty, structurally complex things. Some fungi do not - and we call them the sugar fungi. They compete with bacteria ALOT, but they are not fungi you particularly want to have around.

Water molds grow in many water-logged conditions. They do not do well in open water, they need surfaces in order to grow.

The "bad guy" Oomycetes generally require reduction in O2 typical of water-logged conditions in order to grow. There is a different classifcation system that labels the oomycetes as something else, but I have never been taught that system of classification. Not sure how accepted it is in academia. Darn taxonomists keep finding out new things and re-classifying the groups of fungi. And then they find out they were wrong, and change everything back again. I can't keep up.

But, in any case, oomycetes, or water fungi, or water molds, whatever, require temperature, and decent water films in order to grow and reproduce. The plant pathogens generally require reduce doxygen.

Soil in the winter is often water-logged, but you don't get any problem with water molds then. Why not? Temperature. Not enough bacterial growth to drop oxygen content until the soil begins to warm up, and/or roots start pumping exudates out. But when the temperature warms up, the foods arrive, then they grow, use up oxygen, and drop O2, so the water molds say, Thanks!

Most water molds require a true water film to reproduce. The spores produce a "swimmer" stage, and they need the water in order to disperse. Splashing from the soil surface to the leaves can be a source of these diseases on to the plant leaves.

Check any mycology textbook to look at this taxonomic division. My favorite general text is Webster's Introductory Mycology. Getting a bit old, I suppose, however.......

Elaine Ingham
President, Soil Foodweb Inc.
SFI Corvallis, OR
SFI Port Jefferson, NY
SFI Lismore, NSW, Australia
SFI Hilversum, The Netherlands
SFI Cambridge, New Zealand
www.soilfoodweb.com

 

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Received on Sat Jan 03 2004 - 21:15:43 EST

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