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More really good stuff ___ Key references - covering important topics in soil health and soil quality




Here's the article on red clover and micronutrient mining with VAM's (you'll really like this one - has to do with the value of commercial mycorrhizal inoculants) - this is a really good article; glad I had the foresight to archive it from bionet.plants in 1995 - thank God for Usenet, Unix, ibiblio and the Internet.

Nice photographs!

LL
()()()()()
From niemirab@student.msu.edu Fri Mar  3 21:36:59 EST 1995
Article: 5512 of bionet.plants
(Brendan A. Niemira)
Newsgroups: bionet.plants
Subject: Re: Mycorhizzae vs. Fertilizer
Date: Thu, 02 Mar 1995  11:04 est
Organization: Michigan State University

In Article <3j30kl$s12@vixen.cso.uiuc.edu> "egrunden@prairienet.org (Eric Grunden)" says:
>
> If a person was to isolate a fungus that would form a
> mycorhizzae relationship with an agronomic crop, would
> innoculation of that fungus into the field (once it
> became established) be an effective method for reducing
> the need for commercial fertilization? Wouldn't the
> "strength/abundance" of the fungi grow exponentially with
> the passing of years?

For agronomic crops, you're talking about vesicular arbuscular mycorrhizae (VAM), a symbiotic endomycorrhizal fungus. These are ubiquitous anyway, and not very
host-specific, so there is very little need to inoculate the field in order
to introduce them. The big trick is getting them to colonize your crop plant to such an extent that fertilizer inputs can be reduced. You can a) build up
the population in the soil such that even moderately active fungi result in
heavy coloniazation, b) put something in the soil to stimulate the activity
of smaller populations to get heavy colonization.

Crop rotations have been shown to have a definite impact on the population
dynamics of VAM, and work is currently being done (by me, among others) to
determine how the different crop plants differentially select for certain
species of VAM among all that are availible in the soil.

Other workers have shown that certain natural, plant-produced chemicals can
stimulate the existing VAM to higher levels of activity. These chemicals were originally derived from red clover, a popular sequence in crop rotations. This
may shed some light on why rotations are effective w/regard to VAM.

Good luck.
...........

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Brendan A. Niemira | "You know your Shelley, Bertie."
Dept. Botany and Plant Path  |   "Oh, am I?"
Michigan State University    |       P.G. Wodehouse
niemirab@student.msu.edu     |       *The Code of the Woosters*
        All opinions expressed are entirely my own.

<><><><>


From: "ARS News Service" <isnv@ars-grin.gov>
To: "ARS News List" <ars-news@ars-grin.gov>
Subject: High CO2 Stimulates Soil-Building "Glue"
Date: Wed, Aug 11, 1999, 11:03 AM


STORY LEAD:
High CO2 Stimulates Soil-Building "Glue"

-----------
ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, dcomis@asrr.arsusda.gov
August 12, 1999
-----------

In the first examination of the effects of high atmospheric carbon dioxide
levels on soil structure, an Agricultural Research Service scientist and
cooperators found that the gas stimulates soil-dwelling fungi to produce
more of a unique protein that greatly amplifies a soil's ability to store
carbon.

The study's results are described in a letter published in the August 12
issue of Nature magazine. One of the letter's authors, ARS soil scientist
Sara F. Wright, previously discovered the protein and named it glomalin. She
suspects it may be the primary glue that holds soil together. Now it appears
that a little of this glue goes a long way toward helping soils keep carbon
out of the atmosphere in the form of carbon dioxide.

Carbon dioxide is a greenhouse gas contributing to possible global warming.

The lead author, Matthias C. Rillig, is with the Carnegie Institution of
Washington at Stanford, Calif., as is Christopher B. Field. The fourth
author, Michael F. Allen, is with the University of California at Riverside.
The researchers studied three different ecosystems: two grasslands in
northern California and chaparral in southern California. In all three, they
found that as more carbon dioxide was pumped into open-top chambers placed
over grassland plants growing outdoors, or in a greenhouse built around
shrubs, glomalin levels rose, along with soil stability.

The high carbon dioxide levels in the air increase the amount of carbon
taken in by plant roots. That gives the fungi more food and enables them to
produce more glomalin. The glomalin glues soil particles together and helps
them clump, improving soil structure. This eases the passage of air and
water through soil, boosting plant yields. It also helps soil resist erosion
and hold in soil carbon -- valuable organic matter that holds nutrients to
recycle slowly to plants.

Farmers can increase glomalin levels further by avoiding plowing and by
growing cover crops year-round if feasible. Fungi need live roots to produce
glomalin.

----------
Scientific contact: Sara F. Wright, ARS Soil Microbial Systems Laboratory,
Beltsville, Md., phone (301) 504-8156, fax 504-8370,
swright@asrr.arsusda.gov.
----------
This item is one of the news releases and story leads that ARS Information
distributes on weekdays to fax and e-mail subscribers. You can also get the
latest ARS news on the World Wide Web at
http://www.ars.usda.gov/is/pr/thelatest.htm.
* Feedback and questions to ARS News Service via e-mail: isnv@ars-grin.gov.
* ARS Information Staff, 5601 Sunnyside Ave., Room 1-2251, Beltsville MD
20705- 5128, (301) 504-1617, fax 504-1648.


<><><>


From isnv@ars-grin.gov Tue Mar 28 12:36:19 2000
Date: Tue, 28 Mar 2000 09:51:57 -0500
From: ARS News Service <isnv@ars-grin.gov>
To: ARS News List <ars-news@ars-grin.gov>
Subject: Adding Microbes to Transplant Mix

STORY LEAD:
Adding Microbes to Transplant Mix Helps Increase Crop Yields

-----------
ARS News Service
Agricultural Research Service, USDA
Jesus Garcia, (301) 504-1627, jgarcia@ars-grin.gov
March 28, 2000
-----------

Tomato and pepper farmers can now add microbes along with their transplant
mix to the arsenal of production practices used to reduce yield losses
caused by soilborne pathogens--including root-knot nematodes.

The microbe-amended transplant mix is being developed by Agricultural
Research Service scientists at the U.S. Horticultural Research Laboratory in
Fort Pierce, Fla., led by Nancy K. Burelle, in cooperation with Gustafson
LLC of Plano, Texas. The transplant mix, called BioYield 213, is amended
with two naturally occurring soil microorganisms--Paenobacillus macerans and
Bacillus amyloliquefacien.

The mix provides the microorganisms with the environment they need to grow
on the root surface of seedlings. Once this occurs, the microbes then
stimulate vigorous growth and improve the health of the transplanted
seedling by triggering the plant's resistance mechanisms. This research is
part of an ongoing ARS effort to provide farmers with alternatives to the
use of methyl bromide, an ozone-depleting soil fumigant being phased out by
2005.

Benefits continue to be observed in seedlings out in the field. Greenhouse
producers can expect to grow seedlings in a shorter time period and farmers
can anticipate 5 to 20 percent yield increases in tomatoes, bell peppers and
even strawberries. The mix will be made commercially available to transplant
producers in the fall after grower trials are concluded.

This research is helping scientists gauge the effectiveness of other
alternatives to methyl bromide. For example, when this technology is
combined with alternative soil treatments such as Telone II and PLANTPRO 45,
levels of crop productivity approach those achieved with methyl bromide. But
results also indicate that combining the new formulations with the commonly
used practice of solarization--a process that creates an inhospitable
environment for detrimental microbes by covering the soil with plastic to
heat it, for 6 to 8 weeks in the summer--does not enhance control of
root-knot nematodes.

As the phasing out of methyl bromide proceeds, this technology will provide
growers with an effective, economical and sustainable alternative component
that they can use with existing methods.

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

----------
Scientific contact: Nancy K. Burelle, ARS U.S. Horticultural Research
Laboratory, Fort Pierce, Fla., phone (561) 462-5861, fax (561) 462-5986,
nburelle@saa.ars.usda.gov.
----------
This item is one of the news releases and story leads that ARS Information
distributes on weekdays to fax and e-mail subscribers. You can also get the
latest ARS news on the World Wide Web at
http://www.ars.usda.gov/is/pr/thelatest.htm.
* Feedback and questions to ARS News Service via e-mail: isnv@ars-grin.gov.
* ARS Information Staff, 5601 Sunnyside Ave., Room 1-2251, Beltsville MD
20705-5128, (301) 504- 1617, fax 504-1648.


<><><>


Date:         Fri, 11 May 2001 08:18:07 -0500
 Reply-To:     Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 Sender:       Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 From:         "Wilson, Dale" <WILSONDO@PHIBRED.COM>
 Subject:      Chitin in laymans terms
 Content-Type: text/plain; charset="iso-8859-1"

 Sanjay,

 > Could someone please give us an explanation in LAYMAN'S
 > language, as to what is Chitin?

 Two basic strategies for mechanical support are found among living things,
bones/muscles and tough, hard shells. Plants, fungi, insects, spiders, and
 crustaceans (including lots of tiny, tiny soil creatures) have shells or
 cell walls.  Most of these exoskeletons and walls are made of sugar
 molecules spun together to make long chains.  The sugar molecules are
 connected by a kind of linkage or bond that is very resistant to breakdown
 (unlike starch, which is easily broken into sugar). The plants make cell
walls mainly out of cellulose, the main constituent of cotton and wood. The animals (and most fungi) that make cell walls and exoskeletons make them out
 of a substance very similar to cellulose called chitin, also fiberous and
hard to break down. It is almost identical chemically to cellulose, except
 the sugar molecules have an amino group (contains N) stuck on the side.

 The fact that chitin contains all this nitrogen has important implications
 ecologically.  Nitrogen is a scarce resource in most systems (well, not if
 you apply 200 lb/a!), and chitin is an important source of N, and sugar in
many systems. There has been great pressure for the evolution of organisms
 that can exploit this resource.  In soils with a large currency of chitin
 (soils with a lot of fungi) there are also many organisms that eat chitin
for breakfast. In such situations, chitin is less effective as armor plate.
 It so happens that nematodes use chitin as armor plate, and of course most
fungi do to. Soil with a high rate of formation and breakdown of chitin is
 less hospitable to nematodes and fungi.  Flora must spend more energy
 defending itself.  Plants have ways of exploiting this situation at the
 root/soil interface.  It is all wonderfully complex and, well, miraculous
 (also very violent on a tiny scale).

 Dale


Date:         Thu, 10 May 2001 23:58:28 -0700
 Reply-To:     Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 Sender:       Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 From:         Don Lotter <don@DONLOTTER.COM>
 Subject:      Chitin, microbes, and soil: an addition to the discussion
 Content-Type: text/plain; charset="iso-8859-1"; format=flowed

 I've been skimming over the discussion on chitin in soil the last week or
two. Rodriguez-Kabana's work on chitin in soil has been really good. Here is the first part of one of his papers. Here is the intro to a paper by him:
 Don Lotter

Naturally-occurring nematode suppressiveness has been reported for several agricultural systems (Stirling et al., 1979; Kerry, 1982; Kluepfel et al.,
 1993), but suppressiveness can also be induced by crop rotation with
antagonistic plants such as switchgrass (Panicum virgatum) (Kokalis-Burelle et al., 1995) and velvetbean (Mucuna deeringiana) (Vargas et al., 1994) or
 organic amendments including pine bark (Kokalis-Burelle et al., 1994),
 hemicellulose (Culbreath et al., 1985) and chitin (Mankau and Das, 1969;
 Spiegel et al., 1986; Rodríguez-Kábana and Morgan-Jones, 1987). A major
 component of the suppressiveness of chitin amendments is believed to be
 biotic and several reports confirm increased numbers of nematode
 antagonistic microorganisms associated with chitin-induced suppressive
 soils (Godoy et al., 1983; Rodríguez-Kábana et al., 1984). Extensive work
 has been done over the past years on fungi associated with chitin
 amendments (Godoy et al., 1983; Rodríguez-Kábana et al., 1984); however,
 information on bacterial community structure and the role of bacteria in
 chitin-induced suppressiveness is still very limited. We chose chitin
 amendments as a model system to study the effect of suppressiveness on
 bacterial diversity in the soil and endorhiza. Endophytic bacteria were
 included in this study because they colonize the same root tissues as
 sedentary plant-parasitic nematodes. This association of endophytic
 bacteria with nematodes throughout the nematode life cycles makes these
 bacteria excellent candidates for biocontrol strategies.

 Chitin is a structural component of some fungi, insects, various
 crustaceans and nematode eggs. In egg shells of tylenchoid nematodes,
 chitin is located between the outer vitelline layer and the inner lipid
layer and may occur in association with proteins (Bird and Bird, 1991). The
 breakdown of this polymer by chitinases can cause premature hatch,
 resulting in fewer viable juveniles (Mercer et al., 1992). In the soil,
 chitinases are produced by some actinomycetes (Mitchell and Alexander,
 1962), fungi (Mian et al., 1982) and bacteria (Ordentlich et al., 1988;
 Inbar and Chet, 1991), but chitinases are also released by many plants as
part of their defense mechanism against various pathogens (Punja and Zhang,
 1993) and plant-parasitic nematodes (Roberts et al., 1992). Chitinases
 depolymerize the chitin polymer into N-acetylglucosamine and chitobiose.
 Further microbial activity results in the deamination of the sugar and
accumulation of ammonium ions and nitrates (Rodríguez-Kábana et al., 1983).
 Nematicidal concentrations of ammonia in association with a newly formed
 chitinolytic microflora are believed to cause nematode suppressiveness
(Mian et al., 1982; Godoy et al., 1983). Benhamou et al. (1994) have shown
 that chitosan, the deacetylated derivative of chitin, induces systemic
 plant resistance against Fusarium oxysporum f.sp. radicis-lycopersici in
 tomato when applied as a seed treatment or soil amendment. This suggests
 that plant defense mechanisms might contribute to the overall nematode
 suppression. Our objective was to determine if the chitin-mediated
suppression of plant parasitic nematodes is related to changes in bacterial
 communities in soils, rhizospheres or within cotton roots.

 From:
 Chitin-mediated changes in bacterial communities of the soil, rhizosphere
 and within roots of cotton in relation to nematode control

 Soil Biology and Biochemistry
 Volume 31, Issue 4  April 1999   Pages 551-560
 J. Hallmann1, R. Rodríguez-Kábana and J. W. Kloepper*

 Biological Control Institute, Alabama Agricultural Experiment Station,
Department of Plant Pathology, Auburn University, Auburn, AL 36849-5409, USA

 Abstract
 Changes in microbial communities associated with nematode control were
 studied by comparing population numbers of fungi and bacteria in the soil
and in internal root tissues (endorhiza) in non-amended and chitin-amended
 soils. Addition of chitin to soil at 1% (w/w) eliminated plant-parasitic
 nematodes in a first planting of cotton cv. `Rowden' and significantly
reduced Meloidogyne incognita infestation in a second planting, confirming
 long-term nematode suppressiveness induced by this organic amendment. The
 chitin amendment was associated with an increase in fungal and bacterial
 populations, especially those with chitinolytic activity. The bacterial
 communities of soil, rhizosphere and endorhiza were assessed by examining
 the taxonomic diversity of recoverable bacteria based on identification
 with fatty acid analysis of sample sizes of 35 soil and rhizosphere
 bacteria and 25 endophytic bacteria. All major bacterial species which
 formed at least 2% of the total population in non-amended soils and
 rhizospheres also occurred with chitin amendment. In contrast,
 chitin-amended soils and rhizospheres yielded several species which were
 not found without chitin amendment, including Aureobacterium testaceum,
 Corynebacterium aquaticum and Rathayibacter tritici. Burkholderia cepacia
was recovered from both amended and non-amended soils and rhizospheres, but
 it was most abundant with chitin amendment at the end of the first cotton
 planting. Soil was probably the major source for bacterial endophytes of
 cotton roots, since nearly all endophytic bacteria were also found in the
 soil or rhizosphere. However, two dominant genera in the soil and
 rhizosphere, Bacillus and Arthrobacter, were not detected as endophytes.
 Chitin amendment exhibited a further specific influence on the endophytic
bacterial community; Phyllobacterium rubiacearum was not a common endophyte
 following chitin amendment, even though chitin amendment stimulated its
 populations in non-planted soil. Burkholderia cepacia, found in similar
 numbers in the soil of both treatments, was the dominant endophyte in
plants grown in chitin-amended soil but rarely colonized cotton roots grown in non-amended soil. These results indicate that application of an organic
 amendment can lead to modifications of the bacterial communities of the
 soil, rhizosphere and endorhiza.


From "The American Heritage Dictionary of the English Language",
 American Heritage Publishing Co., INC. and Houghton Mifflin Company.

 chi-tin  n. A simitransparant horny substance, primarily a
 mucopolysaccharide, forming the principal component of crustacean
 shells, insect exoskeletons, and the cell walls of certain fungi.


Date:         Wed, 6 Jun 2001 10:38:09 +0200
 Reply-To:     Wiegand@lufa-sp.vdlufa.de
 Sender:       Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 From:         Klaus Wiegand <WIEGAND@LUFA-SP.VDLUFA.DE>
 Organization: Landw. U.-& Forsch.-Anstalt Speyer
 Subject:      chitin

 relating to the recent discussion (raised by dale wilson) on
 chitin-producing fungi, i ran upon an interesting paper on that
 topic:



 Are chitinolytic rhizosphere bacteria really beneficial to
 plants?
 Wietse de Boer & J.A. van Veen
 Netherlands Institute of Ecology, Centre for Terrestrial Ecology,
 Department of Plant-Micro-organism Interactions,
 P.O. Box 40,
 6666 ZG Heteren,
 The Netherlands.
 E-Mail: wdeboer@cto.nioo.knaw.nl

 The observations of mycolysis by chitinolytic bacteria have
 stimulated research on possible application of these bacteria for
 biocontrol purposes. The focus has been on rhizosphere bacteria
 as they should be adapted to the environment where
 plant-pathogenic fungi infect roots.  Chitinolytic rhizosphere
 isolates, showing in vitro antifungal effects have therefore been
 tested for their ability to protect plants against infection by
 plant pathogens.  In several cases these strains reduced disease
 symptoms significantly under controlled greenhouse conditions.
 However, application of such strains under field conditions has
 been far less successful, and it is not at all clear that
 mycolytic activities should be expected under field conditions.
 Before this issue can be resolved information is needed about the
 ecological function of bacterial chitinases including
 environmental conditions that might promote chitinase production
 and mycolytic activity.

 In this paper it will be argued that chitinases of rhizosphere
 bacteria are most likely involved in mycoparasitism and defence
 against lysis by fungi.  Obviously, mycoparasitic growth of
 chitinolytic rhizosphere bacteria could be an important mechanism
 to control plant-pathogenic fungi.  However, chitinase production
 in soil bacteria, including potential biocontrol strains, is
 repressed by small organic substrates like sugars and amino
 acids. This indicates that mycolytic activity does only occur
 when no other growth substrates are available i.e. under
 starvation conditions.  Hence, the release of organic compounds
 by the root is expected to repress mycolytic activities of most
 chitinolytic rhizosphere bacteria.  This does, however, not
 suggest that the search for biocontrol strains is futile, but
 indicates that knowledge of chitinase expression and repression
 must be taken into account during this process.

 A potential negative effect of chitinolytic bacteria may be
 exterted on mycorrhizal development.  In fact, the starvation
 conditions in the bulk soil, into which mycorrhizal hyphae are
 extending from the root, should promote mycolytic activities.
 Therefore, study of interactions between chitinolytic strains and
 mycorrhizal fungi should be part of biocontrol studies.

 -----


 klaus

Date:         Wed, 6 Jun 2001 08:42:05 -0500
 Reply-To:     Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 Sender:       Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 From:         "Wilson, Dale" <Dale.Wilson@PIONEER.COM>
 Subject:      Re: chitin
 Content-Type: text/plain; charset="iso-8859-1"

 Klaus,

 > i ran upon an interesting paper on that topic:

This is a really interesting subject. The other day we had Gary Harman here
 for a little seminar.  Gary is the guy who developed the
 rhizoplane-competent Trichoderma harzianum strain T-22.  He showed nice
pictures of how the Trichoderma eats little holes in the cell wall of other
 fungi using chitinase (among other enzyme tricks).

 > "application of such strains under field conditions has
 > been far less successful, and it is not at all clear that
 > mycolytic activities should be expected under field conditions.
 > Before this issue can be resolved information is needed about the
 > ecological function of bacterial chitinases including
 > environmental conditions that might promote chitinase production
 > and mycolytic activity." (de Boer and van Veen)

Trichoderma too has been more consistently beneficial in the greenhouse. I think that the field soil environment is a veritable zoo, including, besides
 fungi, bacteria, and actinomycetes, microarthropods (and protozoa?) that
feed on fungi. Greenhouse soils are probably much simpler systems. BTW, we see consistent and somewhat mysterious growth enhancement in the field from
 seed treatment with systemic neonicotinoid insecticides.  Probably, we are
 suppressing some little critter in the root zone.

 > "chitinase production
 > in soil bacteria, including potential biocontrol strains, is
 > repressed by small organic substrates like sugars and amino
 > acids. This indicates that mycolytic activity does only occur
 > when no other growth substrates are available i.e. under
 > starvation conditions." (de Boer and van Veen)

 And this may be where plant roots come in.  They leak small organic
molecules onto the rhizoplane and alter the ecology. And they snap up N and
 P.  So rhizoplane colonizers are confronted with a substrate-rich, but
 nutrient-poor niche, that may favor mycoparasites that can obtain N by
 breaking down fungi.  Iron availability too may be a key player in some of
 these systems (thinking of some of the Pseudomonads).  God this is
 interesting!

What I think is happening (and I am going way, way out on a speculative limb
 here!) is that plants exploit this situation, producing a mycoparasitic
 environment on the rhizoplane, creating rapid N-turnover, and suck out N
 from the system.

 Gary presented evidence that colonization by his strain of Trichoderma can
 often greatly enhance N uptake, reducing the need for N application.  I
 can't vouch for their data, and they ARE trying to peddle their wares, but
 the results looked pretty encouraging.

 I just did a little literature search: "(chitinase or chitinolytic) and
 (hyperparasitism or mycoparasitism)"  All eight papers were about
fungus-fungus parasitism. Also did a search on "(chitinase or chitinolytic)
 and biocontrol"  I will send these if anyone is interested.

 Dale

Date:         Thu, 7 Jun 2001 08:02:19 +0800
 Reply-To:     Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 Sender:       Sustainable Agriculture Network Discussion Group
               <SANET-MG@LISTS.IFAS.UFL.EDU>
 From:         David Menne <menne@IINET.NET.AU>
 Subject:      Re: chitin
 Content-Type: text/plain; charset=us-ascii

Researching references for an article "Enzymatically improving infant nutrition
 in developing countries [particularly KwaZulu/Natal]" (see
 http://www.plantsfood.com/infantenzyme.htm), I came across the interesting
 claims that chitinases have proven active against human pathogens such as
Listeria monocytogenes, Clostridium botulinum, Bacillus cereus, Staphylococcus
 aureus and E coli.

I have a general interest in the mechanics of what I suppose one could call health-promoting food production; and possibly a need to be aware of destructive
 food production processes [such as boiling the hostel cabbage to a pulp -
 Greytown High School boarding hostel, 1950's]; and would value any related
references which might/should turn up or be in the databases of those following
 this thread.



<><><>