Doug and I each attended different lectures on mycorrhizae by Jeff Lowenfels at the MOSES Midwest Organic Farming Conference a few weeks ago, and we both felt Lowenfels’ talks on mycrorrhizal fungi were some of the best info we got at the conference.  It’s sent me on a quest to learn more about them.

..Mushrooms are the flowers of fungus. (photo credit http://www.geograph.org.uk/photo/1585644

If you have ever let a no-man’s land develop in the back of your refrigerator, then gotten brave, removed and uncapped those long-forgotten leftovers, you know all too well what fungal hyphae look like.

What is growing on that long-gone casserole is our best friend.  All those tiny hairs can connect to plant roots and extend their root reach further out into the surrounding soil.  But that is just the beginning.

Check out Paul Stamets: 6 ways mushrooms can save the world.

Mycorrhizal fungi produce a protein called glomalin.  This substance was just discovered in 1996 by soil scientist Sara R. Wright, and its sticky nature helps turn a bunch of loose silt, sand and clay particles into organic matter.  It stores carbon and it makes the soil dark brown.  This stuff is huge, and we have actually known about it for less than 10 years.

The USDA archive on soil calls this sticky protein the unsung hero of soil carbon storage.  The U.S. Department of Energy recently funded a study of carbon storage and soil quality and showed that glomalin accounts for 27 percent of the carbon in the soil and is a major component of organic matter.  Glomalin can last in the soil for 7 to 42 years, depending on conditions.

Photo of glomulin. the threadlike filaments are hyphae, and the substance coating them is glomalin.

Glomalin improves soil tilth.    Experienced, sustainable farmers are masters of rating soil tilth by picking up a handful and exploring its feel.  That is the feel of soil that can better withstand both drought and heavy rain events.  (Sound like the kind of weather we are getting more of?)

How can we get this wonder substance in our soil?  There is only one way to get glomalin:  micorrhizal fungi.  The fungi’s hyphae function as pipes  that pull in more water and nutrients to the plant.  They make their hyphae with carbon supplied from the plant.  The glomalin gives those delicate hyphae the rigidity they need to span those vast distances from one soil particle to the next.  As old hyphae stop transporting nutrients, their glomalin becomes part of the soil, sticking particles of sand silt and clay to organic matter into little lumps that can stand up to wind and water erosion much better than glomalin-deficient soils.

Growing plants for the specific purpose of managing glomalin production makes a lot of sense.  Lowenfels had a couple of suggestions to manage your glomulin crop.  To get the gritty nitty, read his  book, Teaming with Microbes: A gardener’s guide to the soil-food web.

1. Plant the kind of plants that have a symbiotic relationship with mycorrhizal fungi.  There are a few plants that don’t need them, and they exude a substance that actually retards mycorrhizal growth.  The Brassica family, which includes cabbage, broccoli and mustards, is particularly hard on your ability to develop a healthy mycorrhiae-filled soil.
2. Don’t rototill.  Lowenfels says just tuck seeds into the ground.  “Don’t destroy the whole soil structure to plant a few seeds.  And when you put compost on the ground, you don’t need to till it in.  He says the food web will pull it down into the soil.  If you stifle the growth of a cover crop using a roller crimper (see my previous post), the dead remains of their roots will serve as ideal passage ways for the fresh roots of your newly-planted edible crops.
3. Don’t compact soil.  While you have to get yourself and some equipment into your crop rows, the less often and lighter the load, the better for your mycorrhiza and soil tilth.
4. Add mycorrhizae to roots of plants being transplanted.  Lowenfels chose not to recommend any particular mycorrhiae supplier, but urged people to check out several and decide who to go with.
5. Don’t over fertilize.  Keep the ratio below 10/10/10, and instead, consider providing as much of your nutrients as possible from compost in order to enrich your soil tilth.
   

   ..More fungus flowers (photo credit http://commons.wikimedia.org/wiki/File:Fungus-IMG_3248.JPG

I originally thought I was going to jump right in to growing grapes and garden veggies, but I am actually starting out cultivating cover crops and glomalin  And even after I get those beds of edible plants established, I’ll be doing them an enormous favor if I plant some restorative cover crop, Mycorrhizae-coated roots and all, during the off season or in alternate years.