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Re: [compost_tea] Re: adding VAM ?



Elaine,
 
Quite often, mycorrhizal inoculum manufacturers have formulated their inoculum ingredients to work efficiently with the spores, hyphae, and host plant root fragments containing spores and hyphae.  When those ingredients are mixed into the tea, you lose the biological design of the manufacturer.  Making probe holes about 10 inches into the soil around the plants and putting about a teaspoon of inoculum down each hole and then pushing the soil in at the top of the hole will work quite well.  (Depending upon the manufacturer... some may require more inoculum because they have a low spore count.)  Where to place the holes has to be thought out too.  If a plant was recently planted, poking holes in the ground a couple feet or more away from the plant probably isn't going to be any where near the plant's roots.  For most AM fungi, the hyphae are more infectious than the spores. 
 
Also, if you mix mycorrhizal inoculum into your tea, there needs to be constant agitation or the spores can settle or float to the top and you will have serious application problems.  With the inoculum mixed into tea there is also the problem of trying to figure out how much to apply. 
 
For well established plants like trees, a set of holes out at the drip line about 10 inches deep and a foot apart will work fine.  I like to get in close to the trunk 2-3 feet and put another set of holes in the soil so the mycorrhizal fungi can grow out from the plant as well as get into the feeder roots out around the drip line. 
 
I've found that for well established grapes and roses, six probe holes into the soil close the plants (about 3 inches from the trunk of the plant) works quite well.
 
If a tree is surrounded by turf grass, do a core aeration and mix the inoculum with carrier material (sand or trace minerals) and use a drop spreader to apply the inoculum.  Then water the area down well.  Most grasses will colonize to about 50% and the roots are mingled with the tree roots.  The AM fungi will vector over from the grass roots onto the tree roots.  Cover crops in between grape vines (if they are mycorrhizal) can make very nice vectoring agents for getting the mycorrhizal fungi onto the underlying grape roots. 
 
The reason we want the inoculum on or as close to the plant roots as possible is that there is a substance called (flavonoids, flavonols, flavonone) which is part of the exudate coming out of the roots which serves as a trigger to cause the AMF spores to germinate or the AMF hyphae to start growing.  In some cases, a combination of carbon dioxide and flavonols are the triggering agents, in other cases, only the flavonols are the triggering agents.  There is a company in the Midwest that now makes a flavonol product which can be mixed with water and then put down as a soil drench and will cause a much higher colonization rate with the AM fungi.  That product can not be mixed with tea because the bacteria will eat it all up.  It also can't be put into the inoculum or it will cause the spores to germinate in the inoculum or the hyphae to start growing.  Once the spores germinate or the hyphae start growing they have a rather short time to work their way into the roots of a plant.  It's the plant that feeds the AM fungi and if it doesn't get hooked up fairly promptly the fungi will expend it's food and die.  This is why we want it near the roots of the plant.  Probe holes work slick when you can get in among a bunch of roots.  If you take the cover crop treatment approach, those plants can easily be treated and the AMF will be sustained nicely and transferred over to the plant roots you are trying to inoculate.
 
There is another bugaboo to be aware of... well three actually...  one has to do with phosphorous.  If a plant has taken up a lot of phosphorous, then colonization by the AM fungi can be totally inhibited to none at all or a very low value.  I think this has something to do with a reduction of the flavonols in the root exudates.  (This is just my hunch.)  I have to do some searching to see if there are any definitive research abstracts available to verify my hunch.  I'm thinking my hunch is true because of no to low colonization rates.  That would be expected if a lot of phosphorous presence in the plant would somehow suppress the flavonol production. 
 
The second bugaboo... once the AM fungi is well colonized in a plants root system, if a lot of free phosphorous is made available to that system, the flow of nutrients through the hyphae of the mycorrhizae will shut down and many of the leaves will turn yellow.  In a severe case, the plant leaves and stems, etc., will dry up and you can lose the plant... like a reverse osmosis.  If you make a tea that has a lot of free phosphorous present, this situation can damage plants that are well colonized with AM fungi.  Bird manures can be the source of a lot of free phosphorous.  I first experienced this situation when I put some Alaska Fish Pellets around a couple of rows of Raspberry plants.  The NPK was 8-5-1.  The leaves of the plants yellowed up from the ground about 3 feet.  A few of the well colonized plants dried up and were lost.  I scraped the fish pellets away and watered the plants well and they all recovered except the ones that dried up. 
 
And a third bugaboo.... this probably won't affect people who use compost teas.  Strange as it may seem one can work with a grower and AM fungi has been applied and CT is being used and don't be too shocked to find the grower applying some sort of systemic fungicide to his plants as a precautionary measure... even after you have spent all kinds of time educating the grower about what to do and what not to do.  You just can't predict what people are going to do.  Well, certain fungicides are super effective at killing AM fungi and you will have to start all over from the beginning with another application.  Surprisingly, some fungicides at low levels are actually stimulating to AM fungi. 
 
Just a few tips to consider..
--Thomas Giannou
http://www.tandjenterprises.com
 
 
----- Original Message -----
Sent: Friday, June 13, 2003 1:16 PM
Subject: Re: [compost_tea] Re: adding VAM ?

Mycorrhizal fungal inocula need to be placed next to the roots.  Addition to compost usually dilutes the spores too much, unless the compost with spores is put into deep aeration cores, like 3 to 4 foot deep, into the soil the roots are in.

Addition to tea has to be just before the plant will be put near the spores. 

So, soil injections with tea to which the spores were added work good.

Root dip into tea with spores (do not add root GELS to get the spores to stick.  the lack of air that results with the gels we have tested kill the fungi). 

Tea with spores applied into aeration holes works great. 

What have I forgotten here?  Any other ways to apply tea with spores?

Elaine Ingham

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