Re: [compost_tea] Re: fungal or bacT dominant plants

From: <soilfoodweb_at_aol.com>
Date: Thu, 29 Jul 2004 10:16:59 -0400
Hi John -

There appears to be a strong correlation with sucessional stage, based on t= he over 100,000 soil samples that we've looked at. That is what I base thes= e conclusions on - we have looked at over 100,000 samples of soil, where th= e following conclusions hold.

If a plant is an early, weedy species, found in grasslands, in annual or bi= -annual conditions, in areas that are typically highly disturbed, then thos= e are usually bacterial-dominated plants. 

If plants are typically found in perennial, not-disturbed environments, the= n they are typically fungal-dominated plants.

The earliest colonizers in both categories (annual versus perennial) requir= e high levels of inorganic nitrogen to germinate and maintain dominance.&nb= sp; Thus, inorganic fertilizers will select for these weedy species in both= situations.  Reduce the available inorganic N levels, and these weedy= species do not thrive.  Your later successional plants do better in c= onditions where inorganic nitrogen is a limited pool in the soil. 
So think of succession - which plants are earliest in the colonization proc= ess of ecosystem successional cycles?  These are the weedy species, an= d they are highly bacterial dominated around the roots.  Later success= ional plant species will be less bacterial dominated, and require more fung= i in the balance.  More fungi to suppress disease, to alter pH to resu= lt in potentially a less strongly alkaline condition.  The most produc= tive grassland situations are balanced, one to one fungal to bacterial biom= ass. 

Remember, we measure biomass, and thus fungi and bacteria can be compared.&= nbsp; Please realize this when you hear the recent criticisms from ag scien= tists who are saying bacteria and fungi can't be compared.  If we asse= ss biomass, then bacterial biomass and fingal biomass can be compared. = ; If you assess numbers, then it is correct that bacterial numbers and fung= al numbers are a silly thing to compare.  But my conclusions are based= on biomass, not numbers.

As you move into forested situations, and into HEALTHY forest soils, the so= il becomes fungal dominated.  The most productive forests are highly f= ungal.  Perhaps 1000 time more fungi than bacteria in healthy old grow= th forest soil.  But bacterial biomass is highest of any ecosystem in = these old growth forests.  It's just that fungal biomass is much, much= higher. 

So, those scientists critsizing me, saying that what I say is "nonsens= e" because thye are showing that bacterial counts are highest in old g= rowth forests just aren't listening to what I say.  At least they are = starting to pay attention to organisms in soil, but plate count methods of = assessing NUMBERS of bacteria are fungi are just silly.  So many wrong= conclusions have been based on that kind of assessment. 

Soil pH correlates with all this.  Highly bacterial soil tends to be v= ery alkaline, while highly fungal-dominated soil tends to be in the 5.5 to = 6.5 range. 

But you have to pay attention to compaction, becuase if the soil compacts a= nd goes anaerobic, then soil pH will drop, and can become VERY acidic. = ; Highly acid soils are indicative of very sick conditions.  The ecosy= stem may well be going "backwards" towards more backterial condit= ions.  Acid soils will become alkaline once the anaerobic conditions a= re alleviated, but that may take thousands of years to shift.  Or only= a decade.  The environmental conditions must be paid attention to.&nb= sp;

But then consider that when we talk about wetland, or riparian systems, thi= ngs are different.  Soils that are water-logged for some part of the y= ear tend to have lower pH, because there may be anaerobic dconditions durin= g water-logged times.  Anaerobic bacteria produce VERY alkaline metabo= lites.  How anaerobic for how long? 

So, think of where your plants occur in the real world.  What is the e= cosystem, or habitat that they normally occur in?  That should give yo= u some good clues about what they like - bacterial, or fungal-dominated con= ditions?

If you have specific questions about plant requirements, just ask me the sp= ecific plant species.  I may have to ask back, where does the plant no= rmally occur?  In forest, or grasslands?  In early successional f= orest, or early successional grasslands?  In weed fields, or mature gr= asslands?  Then we can typically answer the question, even if we haven= 't measured the ratio.

It is safest, however, to actually measure the ratio.......

Elaine

In a message dated 7/29/2004 9:05:13 AM Eastern Daylight Time, "urbanw= orms" <urbanworms_at_houston.rr.com> writes:

>
>Hi Elaine. A couple of  weeks ago Jeff gave a great list of fungal vs= . bac
>dominant plants. But we will never have a complete list so I'm looking = for
>general indicators of where a plant falls on the bac/fungal continuum. =
>
>If we are unsure what a plant's native habitat was like, what other fac= tors can
>be indicators of its microbial preferences? How about a plant's ph
>preference? There seems to be a correlation between acid loving plants = and
>those that thrive in fungal environments.  Is this a reliable indicat= or? Are there
>others?
>
>John
>Urban Worms Recycling &
>Green-n-Healthy Organics
>
>--- In compost_tea_at_yahoogroups.com, soilfoodweb@a... wrote:
>> Good start on the ratios, Jeff!  You've been listening!  And p= utting info
>> together.  Anyone else want to continue to expand it?  
>>
>> Can we put the list on the list serve for people to share?  
>>
>> Elaine R. Ingham
>> Soil Foodweb Inc., Corvallis, Oregon
>> Soil Foodweb Inc., Port Jefferson, New York
>> Soil Foodweb Institute, Lismore Australia
>> Soil Foodweb Institue Cambridge, New Zealand
>> Soil Foodweb Inc., Hilversum, The Netherlands
>> Laboratorios de Soil Foodweb, Culiacan, Mexico
>> Soil Foodweb Inc., Jerome, Idaho
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>Yahoo! Groups Links
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--
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
SFI Culiacan, Mexico
SFI Jerome, Idaho
http://www.soilfoodweb.com


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Received on Thu Jul 29 2004 - 11:39:39 EDT

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