This is most of the first chapter. Please offer critics. Right now, this
book (Teaming with Microbes) and "Omnivore's Dilemma" seem to give the
clearest sense of the direction that gardening and farming should be
going to get us off the dependancy on petroleum based pesticides and
fertilizers.
Again, thank to whoever turned me on to this book.

Teaming with Microbes by Jeff Lowenfels and Wayne Lewis

Chapter 1

What Is the Soil Food Web and
Why Should Gardeners Care?

Plants are in control

Most gardeners think of plants as only taking up nutrients through root
systems and feeding the leaves. Few realize that a great deal of the
energy that results from photosynthesis in the leaves is actually used
by plants to produce chemicals they secrete through their roots. These
secretions are known as exudates. A good analogy is perspiration, a
human's exudate. Root exudates are in the form of carbohydrates
(including sugars) and proteins. Amazingly, their presence wakes up,
attracts, and grows specific beneficial bacteria and fungi living in the
soil that subsist on these exudates and the_ cellular material sloughed
off as the plant's root tips grow. All this secretion of_ exudates and
sloughing-off of cells takes place in the rhizosphere, a zone
immediately around the roots, extending out about a tenth of an inch, or
a couple of millimeters (1 millimeter = 1/25 inch). The rhizosphere,
which can look _like a jelly or jam under the electron microscope,
contains a constantly changing mix of soil organisms, including
bacteria, fungi, nematodes, protozoa, and_ even larger organisms. All
this ³life" competes for the exudates in the rhizosphere, or its water
or mineral content.

At the bottom of the soil food web are bacteria and fungi, which are
attracted to and consume plant root exudates. In turn, they attract and
are eaten_ by bigger microbes, specifically nematodes and protozoa
(remember the_ amoebae, paramecia, flagellates, and ciliates you should
have studied in biology?), who eat bacteria and fungi (primarily for
carbon) to fuel their metabolic_ functions. Anything they don't need is
excreted as wastes, which plant roots are readily able to absorb as
nutrients. How convenient that this production of_ plant nutrients takes
place right in the rhizosphere, the site of root-nutrient_ absorption.
At the center of any viable soil food web are plants. Plants control the
food_ web for their own benefit, an amazing fact that is too little
understood and_ surely not appreciated by gardeners who are constantly
interfering with Nature's system. Studies indicate that individual
plants can control the numbers_ and the different kinds of fungi and
bacteria attracted to the rhizosphere by the exudates they produce
during different times of the growing season, populations of the
rhizosphere bacteria and fungi wax and wane, depending on the nutrient
needs of the plant and the exudates it produces.

Soil bacteria and fungi are like small bags of fertilizer, retaining in
their_ bodies nitrogen and other nutrients they gain from root exudates
and other _organic matter (such as those sloughed-off root-tip cells).
Carrying on the _analogy, soil protozoa and nematodes act as ³fertilizer
spreaders" by releasing ,_the nutrients locked up in the bacteria and
fungi ³fertilizer bags." The nematodes and protozoa in the soil come
along and eat the bacteria and fungi in the,_ rhizosphere. They digest
what they need to survive and excrete excess carbon_ and other nutrients
as waste.

Left to their own devices, then, plants produce exudates that attract
fungi_ and bacteria (and, ultimately, nematodes and protozoa); their
survival depends on the interplay between these microbes. It is a
completely natural system, the very same one that has fueled plants
since they evolved. Soil life provides the nutrients needed for plant
life, and plants initiate and fuel the cycle_ by producing exudates.

Soil life creates soil structure

The protozoa and nematodes that feasted on the fungi and bacteria
attracted_ by plant exudates are in turn eaten by arthropods (animals
with segmented_ bodies, jointed appendages, and a hard outer covering
called an exoskeleton). Insects, spiders, even shrimp and lobsters are
arthropods. Soil arthropods eat_ each other and themselves are the food
of snakes, birds, moles, and other animals. Simply put, the soil is one
big fast-food restaurant. In the course of all_ this eating, members of
a soil food web move about in search of prey or protection, and while
they do, they have an impact on the soil.

Bacteria are so small they need to stick to things, or they will wash
away; to_ attach themselves, they produce a slime, the secondary result
of which is that_ individual soil particles are bound together (if the
concept is hard to grasp,_ think of the plaque produced overnight in
your mouth, which enables mouth_ bacteria to stick to your teeth).
Fungal hyphae, too, travel through soil particles, sticking to them and
binding them together, thread-like, into aggregates.

Worms, together with insect larvae and moles and other burrowing
animals, move through the soil in search of food and protection,
creating path-_ways that allow air and water to enter and leave the
soil. Even microscopic_ fungi can help in this regard (see chapter 4).
The soil food web, then, in addition to providing nutrients to roots in
the rhizosphere, also helps create soil_ structu the activities of
its members bind soil particles together even as they_ provide for the
passage of air and water through the soil.

Soil life produces soil nutrients

When any member of a soil food web dies, it becomes fodder for other
members of the community. The nutrients in these bodies are passed on to
other_ members of the community. A larger predator may eat them alive,
or they may _be decayed after they die. One way or the other, fungi and
bacteria get involved,_ be it decaying the organism directly or working
on the dung of the successful_ eater. It makes no difference. Nutrients
are preserved and eventually are retained in the bodies of even the
smallest fungi and bacteria. When these are in_the rhizosphere, they
release nutrients in plant-available form when they, in_ turn, are
consumed or die.

Without this system, most important nutrients would drain from soil.
Instead, they are retained in the bodies of soil life. Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._ Not so with the nutrients
locked up inside soil organisms, a state known as immobilization; these
nutrients are eventually released as wastes, or mineralized._ And when
the plants themselves die and are allowed to decay, the nutrients they_
retained are again immobilized in the fungi and bacteria that consume
them.

The nutrient supply in the soil is influenced by soil life in other
ways. For example, worms pull organic matter into the soil, where it is
shredded by_ beetles and the larvae of other insects, opening it up for
fungal and bacterial_ decay. This worm activity provides yet more
nutrients for the soil community.

Healthy soil food webs control disease

A healthy food web is one that is not being destroyed by pathogenic and_
disease-causing organisms. Not all soil organisms are beneficial, after
all. As_ gardeners you know that pathogenic soil bacteria and fungi
cause many plain_ diseases. Healthy soil food webs not only have
tremendous numbers of individual organisms but a great diversity of
organisms. . . . Perhaps 20,000 to 30,000 different species make up
its billion bacteria-a healthy population in numbers and diversity.
A large and diverse community controls troublemakers. . . . they
compete with them for exudates and other nutrients, air, water,_ and
even space. If the soil food web is a healthy one, this competition
keeps the_ pathogens in check; they may even be outcompeted to their
death.

Just as important, every member of the soil food web has its place in
the_ soil community. Each, be it on the surface or subsurface, plays a
specific role._ Elimination of even just one group can drastically alter
a soil community. . . . . A healthy soil_ food web won't allow one set
of members to get so strong as to destroy the web._ If there are too
many nematodes and protozoa, the bacteria and fungi on_ which they prey
are in trouble and, ultimately, so are the plants in the area.

And there are other benefits. The nets or webs fungi form around roots
act_ as physical barriers to invasion and protect plants from pathogenic
fungi and_ bacteria. Bacteria coat surfaces so thoroughly, there is no
room for others to attach themselves. If something impacts these fungi
or bacteria and their numbers drop or they disappear, the plant can
easily be attacked.

Special soil fungi, called mycorrhizal fungi, establish themselves in a
symbiotic relationship with roots, providing them not only with-physical
protection but with nutrient delivery as well. In return for exudates,
these fungi provide water, phosphorus, and other necessary plant
nutrients. Soil food web _populations must be in balance, or these fungi
are eaten and the plant suffers.

Bacteria produce exudates of their own, and the slime they use to attach
to_ surfaces traps pathogens. Sometimes, bacteria work in conjunction
with fungi_ to form protective layers, not only around roots in the
rhizosphere but on an_ equivalent area around leaf surfaces, the
phyllosphere. Leaves produce exudates that attract microorganisms in
exactly the same way roots do; these act_ as a barrier to invasion,
preventing disease-causing organisms from entering_ the plant's system.
Some fungi and bacteria produce inhibitory compounds, things like
vitamins and antibiotics, which help maintain or improve plant health;
penicillin_ and streptomycin, for example, are produced by a soil-borne
fungus and a soil borne bacterium, respectively.

All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.
The most important of _these nutrients is nitrogen-the basic building
block of amino acids and,_ therefore, life. The biomass of fungi and
bacteria (that is, the total amount of_ each in the soil) determines,
for the most part, the amount of nitrogen that is_ readily available for
plant use.

It wasn't until the 1980s that soil scientists could accurately measure
the_ amount of bacteria and fungi in soils. Dr. Elaine Ingham at Oregon
State University along with others started publishing research that
showed the ratio of_ these two organisms in various types of soil. In
general, the least disturbed soils_(those that supported old growth
timber) had far more fungi than bacteria,_ while disturbed soils
(rototilled soil, for example) had far more bacteria than_ fungi. These
and later studies show that agricultural soils have a fungal to
bacterial biomass (F:B ratio) of 1:1 or less, while forest soils have
ten times or more_ fungi than bacteria.

Ingham and some of her graduate students at OSU also noticed a
correlation between plants and their preference for soils that were
fungally dominated_ versus those that were bacterially dominated or
neutral. Since the path from_ bacterial to fungal domination in soils
follows the general course of plant succession, it became easy to
predict what type of soil particular plants preferred_ by noting where
they came from. In general, perennials, trees, and shrubs prefer
fungally dominated soils, while annuals, grasses, and vegetables prefer
soils_ dominated by bacteria.

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3). Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria. When does_ this conversion occur?
When ammonium is released in soils that are dominated by bacteria. This
is because such soils generally have an alkaline pH_(thanks to bacterial
bioslime), which encourages the nitrogen-fixing bacteria to thrive. The
acids produced by fungi, as they begin to dominate, lower the pH_ and
greatly reduce the amount of these bacteria. In fungally dominated
soils, much of the nitrogen remains in ammonium form.

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.

Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it. What gardener hasn't seen what table salt does
to a slug? Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil. Since these
microbes are at the very foundation of the_ soil food web nutrient
system, you have to keep adding fertilizer once you start_ using it
regularly. The microbiology is missing and not there to do its job,
feeding the plants.

It makes sense that once the bacteria, fungi, nematodes, and protozoa
are_ gone, other members of the food web disappear as well. Earthworms,
for example, lacking food and irritated by the synthetic nitrates in
soluble nitrogen_ fertilizers, move out. Since they are major shredders
of organic material, their_ absence is a great loss. Without the
activity and diversity of a healthy food web, you not only impact the
nutrient system but all the other things a healthy soil_ food web
brings. Soil structure deteriorates, watering can become problematic,"_
pathogens and pests establish themselves and, worst of all, gardening
becomes_ a lot more work than it needs to be.

If the salt-based chemical fertilizers don't kill portions of the soil
food web, rototilling will. This gardening rite of spring breaks up
fungal hyphae, decimates worms, and rips and crushes arthropods. It
destroys soil structure and_ eventually saps soil of necessary air.
Again, this means more work for you in_ the end. Air pollution,
pesticides, fungicides, and herbicides, too, kill off important members
of the food web community or ³chase" them away. Any chain_ is only as
strong as its weakest link: if there is a gap in the soil food web, the
system will break down and stop functioning properly.

Healthy soil food webs benefit you and your plants

Why should a gardener be knowledgeable about how soils and soil food
webs_ work? Because then you can manage them so they work for you and
your_ plants. By using techniques that employ soil food web science as
you garden,_ you can at least reduce and at best eliminate the need for
fertilizers, herbicides,_ fungicides, and pesticides (and a lot of
accompanying work). You can improve_ degraded soils and return them to
usefulness. Soils will retain nutrients in the_ bodies of soil food web
organisms instead of letting them leach out to God_ knows where. Your
plants will be getting nutrients in the form each particular_ plant
wants and needs so they will be less stressed. You will have natural
disease prevention, protection, and suppression. Your soils will hold
more water.

The organisms in the soil food web will do most of the work of
maintaining plant health. Billions of living organisms will be
continuously at work_ throughout the year, doing the heavy chores,
providing nutrients to plants,_ building defense systems against pests
and diseases, loosening soil and increasing drainage, providing
necessary pathways for oxygen and carbon dioxide._ You won't have to do
these things yourself.

Gardening with the soil food web is easy, but you must get the life back
in_ your soils. First, however, you have to know something about the
soil in which_ the soil food web operates; second, you need to know what
each of the key_ members of the food web community does. Both these
concerns are taken up_ in the rest of Part 1.
--
Billy
Coloribus gustibus non disputatum (mostly)

"Billy Rose" wrote in message
...
This is most of the first chapter. Please offer critics. Right now, this
book (Teaming with Microbes) and "Omnivore's Dilemma" seem to give the
clearest sense of the direction that gardening and farming should be
going to get us off the dependancy on petroleum based pesticides and
fertilizers.
Again, thank to whoever turned me on to this book.

Teaming with Microbes by Jeff Lowenfels and Wayne Lewis

Chapter 1

What Is the Soil Food Web and
Why Should Gardeners Care?

thats good stuff Billy, thanks for sharing it. One resource I found really
interesting & helpful was a guide to organic pastoralism. It really started
me down a different path. It is free to download
http://www.biodynamic.org.nz/guides/intro_ch1.pdf

rob

In article ,
"George.com" wrote:

http://www.biodynamic.org.nz/guides/intro_ch1.pdf

Good read. Thanks for the heads up.
--
Billy
Coloribus gustibus non disputatum (mostly)

Some comments in line


....snip... quite good stuff on the role of microbes and plants

Soil life creates soil structure


A good point.

....

of snakes, birds, moles, and other animals. Simply put, the soil is one
big fast-food restaurant. In the course of all_ this eating, members of
a soil food web move about in search of prey or protection, and while
they do, they have an impact on the soil.


Nicely put.

......

The soil food web, then, in addition to providing nutrients to roots in
the rhizosphere, also helps create soil_ structu the activities of
its members bind soil particles together even as they_ provide for the
passage of air and water through the soil.

Soil life produces soil nutrients

When any member of a soil food web dies, it becomes fodder for other
members of the community. The nutrients in these bodies are passed on to
other_ members of the community. A larger predator may eat them alive,
or they may _be decayed after they die. One way or the other, fungi and
bacteria get involved,_ be it decaying the organism directly or working
on the dung of the successful_ eater. It makes no difference. Nutrients
are preserved and eventually are retained in the bodies of even the
smallest fungi and bacteria. When these are in_the rhizosphere, they
release nutrients in plant-available form when they, in_ turn, are
consumed or die.

Without this system, most important nutrients would drain from soil.
Instead, they are retained in the bodies of soil life.

Not necessarily. Many nutrients are bound fairly tightly to colloidal
surfaces in clay and humous. OK the microbes have a big role in
making humous but they don't make clay.

Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._

Once again not necesarily. If you have sand-based soil you spend you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.


...snip....


All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.

What does 'mineralized' mean here? It's not clear to me.

....snip..


Ingham and some of her graduate students at OSU also noticed a
correlation between plants and their preference for soils that were
fungally dominated_ versus those that were bacterially dominated or
neutral. Since the path from_ bacterial to fungal domination in soils
follows the general course of plant succession, it became easy to
predict what type of soil particular plants preferred_ by noting where
they came from. In general, perennials, trees, and shrubs prefer
fungally dominated soils, while annuals, grasses, and vegetables prefer
soils_ dominated by bacteria.

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3).

I presume they mean NH4+ the soluble ammonium cation (positively
charged particle), NH3 is ammonia gas.

Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria.

Here they mean NO3- the soluble nitrate anion (negtively charged
particle).

Why am I being picky about these being ions (that is charged)?
Because the fact that they are charged is important to understanding
how they bind to colloids, which is key to nutrient retention, a point
which is overlooked by the author.


When does_ this conversion occur?
When ammonium is released in soils that are dominated by bacteria. This
is because such soils generally have an alkaline pH_(thanks to bacterial
bioslime), which encourages the nitrogen-fixing bacteria to thrive. The
acids produced by fungi, as they begin to dominate, lower the pH_ and
greatly reduce the amount of these bacteria. In fungally dominated
soils, much of the nitrogen remains in ammonium form.

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.


All well and good but ignores the fact that the alternative to adding
synthetic nitogen compounds (ignoring nitrogen fixing for now) is
adding manures or urine. It's true that these don't contain much in
the way nitrates from the beast but nitrates are formed naturally in
manure heaps. Gunpowder use to be made from potassium nitrate
gathered from manure heaps.

Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it.

Evidence please. The following isn't good enough.

What gardener hasn't seen what table salt does
to a slug?

Irrelevant. You don't put salt (sodium chloride) in your soil and the
way it kills slugs has little to do with the topic. Remember that
salts are a class of chemical substances which are NOT just common
salt (sodium chloride) in general, although sodium chloride is in fact
a salt.

Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes. In excess synthetic fertiliser AND natural ones will
both kill your plants in the same way. This does not mean that there
are no dissolved salts (as ions) in healthy soil nor does it mean that
you should never add such ions to your soil. You do it every time you
apply chicken manure or **** on the lemon tree.

....snip...


If the salt-based chemical fertilizers don't kill portions of the soil
food web, rototilling will.

Agreed. Once your beds are established heavy soil turning either
manually or mechanically is harmful rather than helpful.


..snip....


Overall this is not a bad chapter but (unless some details are
corrected in later chapters) it is incomplete and in part misleading.
The main point that soil is a living community that must be maintained
is very valuable.

David

In article om,
" wrote:

Some comments in line


...snip... quite good stuff on the role of microbes and plants

Soil life creates soil structure


A good point.

...

of snakes, birds, moles, and other animals. Simply put, the soil is one
big fast-food restaurant. In the course of all_ this eating, members of
a soil food web move about in search of prey or protection, and while
they do, they have an impact on the soil.


Nicely put.

.....

The soil food web, then, in addition to providing nutrients to roots in
the rhizosphere, also helps create soil_ structu the activities of
its members bind soil particles together even as they_ provide for the
passage of air and water through the soil.

Soil life produces soil nutrients

When any member of a soil food web dies, it becomes fodder for other
members of the community. The nutrients in these bodies are passed on to
other_ members of the community. A larger predator may eat them alive,
or they may _be decayed after they die. One way or the other, fungi and
bacteria get involved,_ be it decaying the organism directly or working
on the dung of the successful_ eater. It makes no difference. Nutrients
are preserved and eventually are retained in the bodies of even the
smallest fungi and bacteria. When these are in_the rhizosphere, they
release nutrients in plant-available form when they, in_ turn, are
consumed or die.

Without this system, most important nutrients would drain from soil.
Instead, they are retained in the bodies of soil life.

Not necessarily. Many nutrients are bound fairly tightly to colloidal
surfaces in clay and humous. OK the microbes have a big role in
making humous but they don't make clay.

Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._

Once again not necesarily. If you have sand-based soil you spend you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.


..snip....


All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.

What does 'mineralized' mean here? It's not clear to me.

...snip..


Ingham and some of her graduate students at OSU also noticed a
correlation between plants and their preference for soils that were
fungally dominated_ versus those that were bacterially dominated or
neutral. Since the path from_ bacterial to fungal domination in soils
follows the general course of plant succession, it became easy to
predict what type of soil particular plants preferred_ by noting where
they came from. In general, perennials, trees, and shrubs prefer
fungally dominated soils, while annuals, grasses, and vegetables prefer
soils_ dominated by bacteria.

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3).

I presume they mean NH4+ the soluble ammonium cation (positively
charged particle), NH3 is ammonia gas.

Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria.

Here they mean NO3- the soluble nitrate anion (negtively charged
particle).

Why am I being picky about these being ions (that is charged)?
Because the fact that they are charged is important to understanding
how they bind to colloids, which is key to nutrient retention, a point
which is overlooked by the author.


When does_ this conversion occur?
When ammonium is released in soils that are dominated by bacteria. This
is because such soils generally have an alkaline pH_(thanks to bacterial
bioslime), which encourages the nitrogen-fixing bacteria to thrive. The
acids produced by fungi, as they begin to dominate, lower the pH_ and
greatly reduce the amount of these bacteria. In fungally dominated
soils, much of the nitrogen remains in ammonium form.

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.


All well and good but ignores the fact that the alternative to adding
synthetic nitogen compounds (ignoring nitrogen fixing for now) is
adding manures or urine. It's true that these don't contain much in
the way nitrates from the beast but nitrates are formed naturally in
manure heaps. Gunpowder use to be made from potassium nitrate
gathered from manure heaps.

Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it.

Evidence please. The following isn't good enough.

What gardener hasn't seen what table salt does
to a slug?

Irrelevant. You don't put salt (sodium chloride) in your soil and the
way it kills slugs has little to do with the topic. Remember that
salts are a class of chemical substances which are NOT just common
salt (sodium chloride) in general, although sodium chloride is in fact
a salt.

Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes. In excess synthetic fertiliser AND natural ones will
both kill your plants in the same way. This does not mean that there
are no dissolved salts (as ions) in healthy soil nor does it mean that
you should never add such ions to your soil. You do it every time you
apply chicken manure or **** on the lemon tree.

...snip...


If the salt-based chemical fertilizers don't kill portions of the soil
food web, rototilling will.

Agreed. Once your beds are established heavy soil turning either
manually or mechanically is harmful rather than helpful.


.snip....


Overall this is not a bad chapter but (unless some details are
corrected in later chapters) it is incomplete and in part misleading.
The main point that soil is a living community that must be maintained
is very valuable.

David

Your a damn fine skeptic mate. Let me see if I can make another run at
this. I'll get back to you soon. Sorry, it's a bit late for me and I'm
ever so slightly hammered.
--
Billy
Coloribus gustibus non disputatum (mostly)

In article , Charlie wrote:

On Wed, 20 Jun 2007 22:00:40 -0700, Billy Rose
wrote:


Your a damn fine skeptic mate. Let me see if I can make another run at
this. I'll get back to you soon. Sorry, it's a bit late for me and I'm
ever so slightly hammered.

Crap....you aren't gonna break the rule and post whilst hammered, eh?

So much for the entertainment tonite.

Might as well go finish me bottle and watch the blinks.

Funny thing about the blinks, our yard and garden, in particular, are
full of them. The chemical-heads yards, that I can see while hanging
over the fence, show very few.

I look forward to your's and David's discourse on this.

Charlie

Wish we had blinks here.

Bonne nuit. Schlaft gut.
--
Billy
Coloribus gustibus non disputatum (mostly)

In article om,
" wrote:

Some comments in line


...snip... quite good stuff on the role of microbes and plants

Soil life creates soil structure


A good point.

...

of snakes, birds, moles, and other animals. Simply put, the soil is one
big fast-food restaurant. In the course of all_ this eating, members of
a soil food web move about in search of prey or protection, and while
they do, they have an impact on the soil.


Nicely put.

.....

The soil food web, then, in addition to providing nutrients to roots in
the rhizosphere, also helps create soil_ structu the activities of
its members bind soil particles together even as they_ provide for the
passage of air and water through the soil.

Soil life produces soil nutrients

When any member of a soil food web dies, it becomes fodder for other
members of the community. The nutrients in these bodies are passed on to
other_ members of the community. A larger predator may eat them alive,
or they may _be decayed after they die. One way or the other, fungi and
bacteria get involved,_ be it decaying the organism directly or working
on the dung of the successful_ eater. It makes no difference. Nutrients
are preserved and eventually are retained in the bodies of even the
smallest fungi and bacteria. When these are in_the rhizosphere, they
release nutrients in plant-available form when they, in_ turn, are
consumed or die.

Without this system, most important nutrients would drain from soil.
Instead, they are retained in the bodies of soil life.

Not necessarily. Many nutrients are bound fairly tightly to colloidal
surfaces in clay and humous. OK the microbes have a big role in
making humous but they don't make clay.

-------
I think the nutrients would have a hard-time penetrating the clay. Until
it is turned and amended, clay soils cause puddling. My understanding of
clay is that it is not colloidal. The charge separation in the molecules
that comprise the clay will attach to the hydrophilic (or polar end) of
colloidal material. This is how it is used to clear wine and honey of
colloidal hazes. This clay (bentonite) is made into a slurry ond then
added to the wine. (I'm a bit hazy on how it is done with honey but I'm
sure it is essentially the same thing.) It is turned into a slurry to
increase its' surface area. The retention area of clay soil would be
it's surface and any cracks it develops during the dry season. Clay also
hangs on to its' water making the intake of ions more difficult.So it
seems that the problem with clay soil is its' resistance to flows of
nutrients through them. Eve if there are nutrients in the clay, they
must still find their way to the rhizosphere for them to be of use to
the plant.
-------



Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._

Once again not necesarily. If you have sand-based soil you spend you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.


-------
Here I think the question is hold or block? If the chemical nutrients
are blocked at the surface then that is were some other plant will have
to use them. If you have amended your soil so that the chem ferts can
reach the rhizosphere then, as contended by the authors, it will kill
the bacteria and fungi in the soil and consequently the nematodes and
protoplasms as well. From there on out, the natural fertility of the
soil is dead and you are obliged to renew it by adding more
petrochemical fertilizers to feed you plants.
---------



..snip....


All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.

What does 'mineralized' mean here? It's not clear to me.


-------
I'm with your there. All I know, I found at
http://en.wikipedia.org/wiki/Mineralized . I presume it has to do with
converting NH4 (organic) to HNO3 (inorganic).
--------


...snip..


Ingham and some of her graduate students at OSU also noticed a
correlation between plants and their preference for soils that were
fungally dominated_ versus those that were bacterially dominated or
neutral. Since the path from_ bacterial to fungal domination in soils
follows the general course of plant succession, it became easy to
predict what type of soil particular plants preferred_ by noting where
they came from. In general, perennials, trees, and shrubs prefer
fungally dominated soils, while annuals, grasses, and vegetables prefer
soils_ dominated by bacteria.

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3).

I presume they mean NH4+ the soluble ammonium cation (positively
charged particle), NH3 is ammonia gas.

--------
Sounds right to me. So we are talking NH3 + H2O --- NH4 + OH. The
equilibrium will still be far to the left.
-------



Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria.

Here they mean NO3- the soluble nitrate anion (negtively charged
particle).

Why am I being picky about these being ions (that is charged)?
Because the fact that they are charged is important to understanding
how they bind to colloids, which is key to nutrient retention, a point
which is overlooked by the author.


------
Let's get on the same page here. Colloids, in my understanding, (and I
presume that I couldn't stop you from correcting me even if I tried) are
composed of molecules that have one water soluble end and one that
isn't. The colloidal particle has all its' non-water soluble ends
together in the interior of the particle and exposes its' water loving
end at the surface to its' aqueous solvent or (vice-a-versa). Why is
this important to nutrient retention?
------



When does_ this conversion occur?

-------
In the soil by nitrogen fixing bacteria (those that can make the
conversion from ammonia to nitrate, not N2 to nitrate), hopefully in the
rhizosphere where it will be of use to the plant.
--------


When ammonium is released in soils that are dominated by bacteria. This
is because such soils generally have an alkaline pH_(thanks to bacterial
bioslime), which encourages the nitrogen-fixing bacteria to thrive. The
acids produced by fungi, as they begin to dominate, lower the pH_ and
greatly reduce the amount of these bacteria. In fungally dominated
soils, much of the nitrogen remains in ammonium form.

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.


All well and good but ignores the fact that the alternative to adding
synthetic nitogen compounds (ignoring nitrogen fixing for now) is
adding manures or urine. It's true that these don't contain much in
the way nitrates from the beast but nitrates are formed naturally in
manure heaps. Gunpowder use to be made from potassium nitrate
gathered from manure heaps.


------You were as hammered as I was, weren't you?? Synthetic nitrogen is
a salt, the osmotic pressure it engenders kills the soil flora and
fauna. In manure it comes from the break down (de-aminization) of amino
acids (NH3, not salt), which in turn nurture the soil flora and fauna.
-------


Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it.

Evidence please. The following isn't good enough.


------Look at http://www.biodynamic.org.nz/guides/intro_ch1.pdf that was
pointed out to me by a Kiwi, George.com. At the end of the pdf is the
bit about fertilizer salts and some references. That's all I know mate.
Suspect we'd need a microscope to make the evidence more tangible.
---------


What gardener hasn't seen what table salt does
to a slug?

Irrelevant. You don't put salt (sodium chloride) in your soil and the
way it kills slugs has little to do with the topic. Remember that
salts are a class of chemical substances which are NOT just common
salt (sodium chloride) in general, although sodium chloride is in fact
a salt.


-----------
First line below. Fetilizers are salts. They separate into cations and
anions, creating osmotic pressure that kills the microbes.
-------


Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes. In excess synthetic fertiliser AND natural ones will
both kill your plants in the same way. This does not mean that there
are no dissolved salts (as ions) in healthy soil nor does it mean that
you should never add such ions to your soil. You do it every time you
apply chicken manure or **** on the lemon tree.


--------
Very good point. Chem ferts can be used but we don't know the safe
dilution level. Maybe it's just me but I don't trust recommended dosages
because, I reason that they want you to use them up quickly and come
back for more. Secondly, if you do kill your microbes then you are
relaiant on the chem ferts to feed your plants. Now with ammonia, you
can smell it and a radical increase in the pH of the soil is apt to kill
your plants. So don't apply, if you can smell it. Also it (nitrogen) can
be safely added as protein. Microbes won't break it down if products
become toxic.
-------


...snip...


If the salt-based chemical fertilizers don't kill portions of the soil
food web, rototilling will.

Agreed. Once your beds are established heavy soil turning either
manually or mechanically is harmful rather than helpful.


-----
Right on, right on.
------



.snip....


Overall this is not a bad chapter but (unless some details are
corrected in later chapters) it is incomplete and in part misleading.
The main point that soil is a living community that must be maintained
is very valuable.

David


It always seems the more we know, the less we know. I was surprised that
most of the books that I turned to to get some background on the
interaction between plants and soils, had very little information. It
was like I was looking for physiology and the books were giving me
anatomy.

Thanks for the questions because I think I have a better grasp of the
subject now.

Scratch yer Crater,

--
Billy
Coloribus gustibus non disputatum

"Bill Rose" wrote in message news:rosefam-77CF7A.
...

Not necessarily. Many nutrients are bound fairly tightly to colloidal
surfaces in clay and humous. OK the microbes have a big role in
making humous but they don't make clay.

-------
I think the nutrients would have a hard-time penetrating the clay. Until
it is turned and amended, clay soils cause puddling.

Yes if all you have is clay, I was talking about clay as a component
of soil, like humus, not pure clay. My place has about 4-6 in of dark
brown topsoil over 3-8 ft of yellow plastic clay. If I ever turn up
the clay it is unmanageable. The topsoil which is clay-based comes
with a component of silt and organic matter to which I add more
compost, gypsum (a salt BTW), garden lime and dolomite (salts),
chicken litter and horse manure. After a year it holds water and
allows infiltration but drains quite well (although I still build up
my beds) and it holds nutrients wonderfully.

The gypsum is Calcium Sulphate which is slightly soluble, it helps to
break up clay by binding to the surface of very small particles and
allowing them to clump, see below on colloids. The dolomite and lime
raise the pH (my soil is naturally 5.5, I like it about 6.5 for most
things) and supply Calcium and Magnesium ions.

The plastic clay underneath acts like a freaking huge sponge, it means
my pasture grows for months after rain as the clay slowly gives up the
water it absorbs during rain.

My understanding of
clay is that it is not colloidal.

It is. See below.

The charge separation in the molecules
that comprise the clay will attach to the hydrophilic (or polar end) of
colloidal material. This is how it is used to clear wine and honey of
colloidal hazes. This clay (bentonite) is made into a slurry ond then
added to the wine. (I'm a bit hazy on how it is done with honey but I'm
sure it is essentially the same thing.) It is turned into a slurry to
increase its' surface area. The retention area of clay soil would be
it's surface and any cracks it develops during the dry season.

This is a bit confusing, we will get to a better coverage of particle
size, charge and colloidal behaviour later.

Clay also
hangs on to its' water making the intake of ions more difficult.

It does hold water but this does not prevent ion intake.

So it
seems that the problem with clay soil is its' resistance to flows of
nutrients through them. Eve if there are nutrients in the clay, they
must still find their way to the rhizosphere for them to be of use to
the plant.
-------

There is no reason that plant root hairs cannot absorb nutrient
directly from clay particles.




Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._

Once again not necesarily. If you have sand-based soil you spend you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.


-------
Here I think the question is hold or block? If the chemical nutrients
are blocked at the surface then that is were some other plant will have
to use them. If you have amended your soil so that the chem ferts can
reach the rhizosphere then, as contended by the authors, it will kill
the bacteria and fungi in the soil and consequently the nematodes and
protoplasms as well. From there on out, the natural fertility of the
soil is dead and you are obliged to renew it by adding more
petrochemical fertilizers to feed you plants.
---------

I think this is an extreme view, I mainly use manures but will use
synthetics in some cases. Used judiciously AND combined with
appropriate maintenance of organic matter and soil structure there is
no reason for synthetics to be harmful.. Where they ARE harmful is
when people think they can use them without attending to the other
components. Manures are more foolproof to use without too much
thought, provided you don't overdo it when fresh, as they contain
organics, microbes etc as well as the raw nutrients.

..snip....

All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.

What does 'mineralized' mean here? It's not clear to me.


-------
I'm with your there. All I know, I found at
http://en.wikipedia.org/wiki/Mineralized . I presume it has to do with
converting NH4 (organic) to HNO3 (inorganic).
--------


I think this might be it.
http://en.wikipedia.org/wiki/Mineralization_%28soil%29

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3).

I presume they mean NH4+ the soluble ammonium cation (positively
charged particle), NH3 is ammonia gas.

--------
Sounds right to me. So we are talking NH3 + H2O --- NH4 + OH. The
equilibrium will still be far to the left.
-------


No in soil it will be far to the right because there is excessive
water compared to the ammonia. This is unless the soil is very dry or
you have added large amounts of ammonia. This is why the Nitrogen
content of fresh poultry manure is fleeting (and why it takes your
breath away) because it emits NH3 unless you get it into the soil with
lots of other stuff and water where it can be diluted and absorbed.



Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria.

Here they mean NO3- the soluble nitrate anion (negtively charged
particle).

Why am I being picky about these being ions (that is charged)?
Because the fact that they are charged is important to understanding
how they bind to colloids, which is key to nutrient retention, a point
which is overlooked by the author.


------
Let's get on the same page here. Colloids, in my understanding, (and I
presume that I couldn't stop you from correcting me even if I tried) are
composed of molecules that have one water soluble end and one that
isn't. The colloidal particle has all its' non-water soluble ends
together in the interior of the particle and exposes its' water loving
end at the surface to its' aqueous solvent or (vice-a-versa). Why is
this important to nutrient retention?
------


Colloids are substances that are VERY finely divided, they may or may
not have polar bits on the surface. You can have inorganic colloids
(eg clay) or organic (humous). The fact that they are composed of
very small particles means for a given weight their surface area is
huge.

See http://en.wikipedia.org/wiki/Particle_size

Surfaces are where all sorts of interesting chemical and physical
changes happen. So colloids can be very active in living and unliving
systems. Clay colloids are the sort with charged surfaces (especially
negative charges) so they can bind positively charged ions like metals
(Calcium2+, sodium+, potassium+ etc) or ammonium NH4+. This is how
they hold mineral nutrients. This is one reason that sodised soil
(excessive salt, sodium chloride) are infertile because the sodium
ions (that plants only need tiny amounts of) displace all the others
(eg potassium) that they need lots of.


When does_ this conversion occur?

-------
In the soil by nitrogen fixing bacteria (those that can make the
conversion from ammonia to nitrate, not N2 to nitrate), hopefully in the
rhizosphere where it will be of use to the plant.
--------


This isn't right. See
http://en.wikipedia.org/wiki/Nitrogen_fixation

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.


All well and good but ignores the fact that the alternative to adding
synthetic nitogen compounds (ignoring nitrogen fixing for now) is
adding manures or urine. It's true that these don't contain much in
the way nitrates from the beast but nitrates are formed naturally in
manure heaps. Gunpowder use to be made from potassium nitrate
gathered from manure heaps.


------You were as hammered as I was, weren't you??

No. Jober as a sudge. Manure heaps may not be the best way to
describe it, try this.
http://en.wikipedia.org/wiki/Potassium_nitrate


Synthetic nitrogen is
a salt, the osmotic pressure it engenders kills the soil flora and
fauna. In manure it comes from the break down (de-aminization) of amino
acids (NH3, not salt), which in turn nurture the soil flora and fauna.
-------


No. *Excessive* soluble salts kill cells by damaging them with
osmotic pressure. You cannot have living things without soluble
salts. This false distinction between synthetic and natural sources
of such salts is claptrap. The important thing is the whole regime
that use to maintain your soil not whether the chemicals come out of a
chook or a steel pressure vessel. This point about NH3 is also
misleading. You can add natural NH3 in chook poo (mainly as NH4+) or
stuff the synthetic dry gas directly into the soil where it
immediately combines with water to give NH4+. Insofar as the NH3 it
makes no difference. The chook poo might be preferred for other
reasons but not because it is "natural", whatever that means, it's
the same freaking molecule.


Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it.

Evidence please. The following isn't good enough.


------Look at http://www.biodynamic.org.nz/guides/intro_ch1.pdf that was
pointed out to me by a Kiwi, George.com. At the end of the pdf is the
bit about fertilizer salts and some references. That's all I know mate.
Suspect we'd need a microscope to make the evidence more tangible.
---------


The biodynamic guys are extremists in this. They firmly believe that
there is something magical about "natural" substances. Living and
once living things contain some kind of life force in their religion.
This, like all religion, is a matter of faith which can neither be
proved or disproved. For me I see no need to invoke the supernatural
to explain how stuff happens.


What gardener hasn't seen what table salt does
to a slug?

Irrelevant. You don't put salt (sodium chloride) in your soil and the
way it kills slugs has little to do with the topic. Remember that
salts are a class of chemical substances which are NOT just common
salt (sodium chloride) in general, although sodium chloride is in fact
a salt.


-----------
First line below. Fetilizers are salts. They separate into cations and
anions, creating osmotic pressure that kills the microbes.
-------


Dealt with above.


Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes. In excess synthetic fertiliser AND natural ones will
both kill your plants in the same way. This does not mean that there
are no dissolved salts (as ions) in healthy soil nor does it mean that
you should never add such ions to your soil. You do it every time you
apply chicken manure or **** on the lemon tree.


--------
Very good point. Chem ferts can be used but we don't know the safe
dilution level. Maybe it's just me but I don't trust recommended dosages
because, I reason that they want you to use them up quickly and come
back for more.

This safe level stuff is just propaganda. You get the same ions out
of synthetics as "naturals" so why should we assume they behave any
differently. The problem with synthetics is that it is so much more
concenrated it is easier to overdose.

Secondly, if you do kill your microbes then you are
relaiant on the chem ferts to feed your plants. Now with ammonia, you
can smell it and a radical increase in the pH of the soil is apt to kill
your plants. So don't apply, if you can smell it.

Good thinking! But avoiding excess applies equally well to applying
synthetic ammonia as chook poo.

Also it (nitrogen) can
be safely added as protein. Microbes won't break it down if products
become toxic.

I don't know what you are getting at here. What protein would you add
to soil?


It always seems the more we know, the less we know. I was surprised that
most of the books that I turned to to get some background on the
interaction between plants and soils, had very little information. It
was like I was looking for physiology and the books were giving me
anatomy.

Thanks for the questions because I think I have a better grasp of the
subject now.


There are good books out there on soil chemistry that are aimed at the
non technical person whcih are not just shills for chemical companies.

David

In article . com,
" wrote:

"Bill Rose" wrote in message news:rosefam-77CF7A.
...

Not necessarily. Many nutrients are bound fairly tightly to colloidal
surfaces in clay and humous. OK the microbes have a big role in
making humous but they don't make clay.

Lord love a duck, mate. This will take some muckin' about to get
straight. Score one for you, what I would call an emulsion the ignorant
Wikipedia calls a colloidal dispersion. Stupid *******s.


-------
I think the nutrients would have a hard-time penetrating the clay. Until
it is turned and amended, clay soils cause puddling.

Yes if all you have is clay, I was talking about clay as a component
of soil, like humus, not pure clay. My place has about 4-6 in of dark
brown topsoil over 3-8 ft of yellow plastic clay. If I ever turn up
the clay it is unmanageable. The topsoil which is clay-based comes
with a component of silt and organic matter to which I add more
compost, gypsum (a salt BTW), garden lime and dolomite (salts),
chicken litter and horse manure. After a year it holds water and
allows infiltration but drains quite well (although I still build up
my beds) and it holds nutrients wonderfully.

The gypsum is Calcium Sulphate which is slightly soluble, it helps to
break up clay by binding to the surface of very small particles and
allowing them to clump, see below on colloids. The dolomite and lime
raise the pH (my soil is naturally 5.5, I like it about 6.5 for most
things) and supply Calcium and Magnesium ions.

The plastic clay underneath acts like a freaking huge sponge, it means
my pasture grows for months after rain as the clay slowly gives up the
water it absorbs during rain.
Well, not so much a sponge as a stopper. We call it hardpan. The water
can't go anywhere. Also makes it hard for trees to set tap roots and
find water, which then require watering.

My understanding of
clay is that it is not colloidal.

It is. See below.

The charge separation in the molecules
that comprise the clay will attach to the hydrophilic (or polar end) of
colloidal material. This is how it is used to clear wine and honey of
colloidal hazes. This clay (bentonite) is made into a slurry ond then
added to the wine. (I'm a bit hazy on how it is done with honey but I'm
sure it is essentially the same thing.) It is turned into a slurry to
increase its' surface area. The retention area of clay soil would be
it's surface and any cracks it develops during the dry season.

This is a bit confusing, we will get to a better coverage of particle
size, charge and colloidal behaviour later.

Clay also
hangs on to its' water making the intake of ions more difficult.

It does hold water but this does not prevent ion intake.
Not if the soil is amended, such as you have.

So it
seems that the problem with clay soil is its' resistance to flows of
nutrients through them. Eve if there are nutrients in the clay, they
must still find their way to the rhizosphere for them to be of use to
the plant.
-------

There is no reason that plant root hairs cannot absorb nutrient
directly from clay particles.
I don't see any disagreement here. Clay impedes the flow of water and
will attempt to bind with passing charged particles. (Need to get an
authority for this.)




Here is the
gardener's truth: when you apply a chemical fertilizer, a tiny bit hits
the rhizosphere, where it is absorbed, but most of it continues to drain
through soil until it hits the water table._

Once again not necesarily. If you have sand-based soil you spend you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.

So what your saying is that you've created an agricultural pot, the
sides and bottom of which is clay and that the nutrients that you put in
the pot, stay in the pot because the clay isn't permeable. RIght?

I'm thinking that the salts can't leave either but I'll revisit that
later.

One observation though, this is the way we try to keep landfills from
contaminating aquifers and how we sequester material from Superfund
sites.

-------
Here I think the question is hold or block? If the chemical nutrients
are blocked at the surface then that is were some other plant will have
to use them. If you have amended your soil so that the chem ferts can
reach the rhizosphere then, as contended by the authors, it will kill
the bacteria and fungi in the soil and consequently the nematodes and
protoplasms as well. From there on out, the natural fertility of the
soil is dead and you are obliged to renew it by adding more
petrochemical fertilizers to feed you plants.
---------

I think this is an extreme view, I mainly use manures but will use
synthetics in some cases. Used judiciously AND combined with
appropriate maintenance of organic matter and soil structure there is
no reason for synthetics to be harmful.. Where they ARE harmful is
when people think they can use them without attending to the other
components. Manures are more foolproof to use without too much
thought, provided you don't overdo it when fresh, as they contain
organics, microbes etc as well as the raw nutrients.

Agreed, but no one uses green animal manures on food crops. Now I've
offered 2 authors, plus references, that contend will damage soil
fertility by killing off the micro-organisms that provide nutrients and
soil structure, if used in excess. Can you tell me what a healthy level
of chem fert is that doesn't harm soil organisms and provide supporting
documentation?

..snip....

All nitrogen is not the same

Ultimately, from the plant's perspective anyhow, the role of the soil
food web_ is to cycle down nutrients until they become temporarily
immobilized in the bodies of bacteria and fungi and then mineralized.

What does 'mineralized' mean here? It's not clear to me.


-------
I'm with your there. All I know, I found at
http://en.wikipedia.org/wiki/Mineralized . I presume it has to do with
converting NH4 (organic) to HNO3 (inorganic).
--------


I think this might be it.
http://en.wikipedia.org/wiki/Mineralization_%28soil%29
So it takes it back to before de-aminization to the amino acids.

One implication of these findings, for the gardener, has to do with the
nitrogen in bacteria and fungi. Remember, this is what the soil food web
means _to a plant: when these organisms are eaten, some of the nitrogen
is retained by_ the eater, but much of it is released as waste in the
form of plant-available ammonium (NH3).

I presume they mean NH4+ the soluble ammonium cation (positively
charged particle), NH3 is ammonia gas.

--------
Sounds right to me. So we are talking NH3 + H2O --- NH4 + OH. The
equilibrium will still be far to the left.
-------


No in soil it will be far to the right because there is excessive
water compared to the ammonia. This is unless the soil is very dry or
you have added large amounts of ammonia. This is why the Nitrogen
content of fresh poultry manure is fleeting (and why it takes your
breath away) because it emits NH3 unless you get it into the soil with
lots of other stuff and water where it can be diluted and absorbed.

Just a little nit-pick. To the left.

NH3 + H2O --- NH4 + OH

1.82 x 10^-5 = ([NH4] [OH]) / (NH3)

The ammonia is on its' way out (as a gas) until it is converted to NO3.




Depending on the soil
environment, this can either remain as_ ammonium or be converted into
nitrate (NO3,) by special bacteria.

Here they mean NO3- the soluble nitrate anion (negtively charged
particle).

Why am I being picky about these being ions (that is charged)?
Because the fact that they are charged is important to understanding
how they bind to colloids, which is key to nutrient retention, a point
which is overlooked by the author.
I'm still having trouble with your use of the term colloids here, in
reference to clay. Clays have stoichiometric formulas colloids
(according to stupid head Wikipedia) have continuous and dispersed
phases. I'm beginning to think that you are referring to is your mixture
of organic material and clay soil as a colloidal despersion or
suspension.


------
Let's get on the same page here. Colloids, in my understanding, (and I
presume that I couldn't stop you from correcting me even if I tried) are
composed of molecules that have one water soluble end and one that
isn't. The colloidal particle has all its' non-water soluble ends
together in the interior of the particle and exposes its' water loving
end at the surface to its' aqueous solvent or (vice-a-versa). Why is
this important to nutrient retention?
------


Colloids are substances that are VERY finely divided, they may or may
not have polar bits on the surface. You can have inorganic colloids
(eg clay) or organic (humous). The fact that they are composed of
very small particles means for a given weight their surface area is
huge.

Na und?

See http://en.wikipedia.org/wiki/Particle_size

Surfaces are where all sorts of interesting chemical and physical
changes happen. So colloids can be very active in living and unliving
systems. Clay colloids are the sort with charged surfaces (especially
negative charges) so they can bind positively charged ions like metals
(Calcium2+, sodium+, potassium+ etc) or ammonium NH4+. This is how
they hold mineral nutrients. This is one reason that sodised soil
(excessive salt, sodium chloride) are infertile because the sodium
ions (that plants only need tiny amounts of) displace all the others
(eg potassium) that they need lots of.


When does_ this conversion occur?

-------
In the soil by nitrogen fixing bacteria (those that can make the
conversion from ammonia to nitrate, not N2 to nitrate), hopefully in the
rhizosphere where it will be of use to the plant.
--------


This isn't right. See
http://en.wikipedia.org/wiki/Nitrogen_fixation

I said not N2 to nitrate which is what "nitrogen fixing" bacteria do.
I'm referring to NH4 --- NO3.

Ah, here is the rub: chemical fertilizers provide plants with nitrogen,
but_ most do so in the form of nitrates (NO3). An understanding of the
soil food_ web makes it clear, however, that plants that prefer fungally
dominated soils ultimately won't flourish on a diet of nitrates. Knowing
this can make a great deal_ of difference in the way you manage your
gardens and yard. If you can cause_ either fungi or bacteria to
dominate, or provide an equal mix (and you can-_just how is explained in
Part 2), then plants can get the kind of nitrogen they prefer, without
chemicals, and thrive.


All well and good but ignores the fact that the alternative to adding
synthetic nitogen compounds (ignoring nitrogen fixing for now) is
adding manures or urine. It's true that these don't contain much in
the way nitrates from the beast but nitrates are formed naturally in
manure heaps. Gunpowder use to be made from potassium nitrate
gathered from manure heaps.

Interesting, I always thought the way was to burn sea shells, grind them
up, add them to water with vegetation, boil, filter, and evaporate.


------You were as hammered as I was, weren't you??

No. Jober as a sudge. Manure heaps may not be the best way to
describe it, try this.
http://en.wikipedia.org/wiki/Potassium_nitrate


Synthetic nitrogen is
a salt, the osmotic pressure it engenders kills the soil flora and
fauna. In manure it comes from the break down (de-aminization) of amino
acids (NH3, not salt), which in turn nurture the soil flora and fauna.
-------


No. *Excessive* soluble salts kill cells by damaging them with
osmotic pressure. You cannot have living things without soluble
salts.

The authors didn't say that any quantity would kill micro-organisms.
That is reflected here somewhere. But with my suspicion that we are
already advised by the instructions on the package to use more than we
really need (my paranoia, if you will) and the if-a-little-bit-is-good,
then-more-must-be-better mentality, serious damage can be done to the
soil. I take full responsibility for my claptrap.


This false distinction between synthetic and natural sources
of such salts is claptrap. The important thing is the whole regime
that use to maintain your soil not whether the chemicals come out of a
chook or a steel pressure vessel. This point about NH3 is also
misleading. You can add natural NH3 in chook poo (mainly as NH4+) or
stuff the synthetic dry gas directly into the soil where it
immediately combines with water to give NH4+. Insofar as the NH3 it
makes no difference. The chook poo might be preferred for other
reasons but not because it is "natural", whatever that means, it's
the same freaking molecule.


Negative impacts on the soil food web

Chemical fertilizers negatively impact the soil food web by killing off
entire_ portions of it.

Evidence please. The following isn't good enough.


------Look at http://www.biodynamic.org.nz/guides/intro_ch1.pdf that was
pointed out to me by a Kiwi, George.com. At the end of the pdf is the
bit about fertilizer salts and some references. That's all I know mate.
Suspect we'd need a microscope to make the evidence more tangible.
---------


The biodynamic guys are extremists in this. They firmly believe that
there is something magical about "natural" substances. Living and
once living things contain some kind of life force in their religion.
This, like all religion, is a matter of faith which can neither be
proved or disproved. For me I see no need to invoke the supernatural
to explain how stuff happens.

OK, OK, I'm no fan of booga booga either. Pick out the watermelon seeds
and enjoy. There is a lot of good science in that pdf. The only time
they lost me was with the "bio-dynamic" calendar and the adding
paramagnetic rock to the soils. Belief is not required. Again, did you
see the excerpts from "Omnivore's Dilemma"?


What gardener hasn't seen what table salt does
to a slug?

Irrelevant. You don't put salt (sodium chloride) in your soil and the
way it kills slugs has little to do with the topic. Remember that
salts are a class of chemical substances which are NOT just common
salt (sodium chloride) in general, although sodium chloride is in fact
a salt.


-----------
First line below. Fetilizers are salts. They separate into cations and
anions, creating osmotic pressure that kills the microbes.
-------


Dealt with above.


Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes.

And I think that is what we are talking about. Excess. If you give the
micro-organisms the organic nutrients they need they will convert them
into the materials needed to create a web of life that supports the soil
and your plants. Where a large and diverse population of
micro-organisms can protect against non-benevolent micro-organisms.
I realize that you don't just use chem ferts but none of them support
the diverse population of organisms that make your soil fertile.
Otherwise you may as well go hydroponic.

We aren't trying to make a goose from Toulouse here, where you "cram" it
full of nutrient so that you can eat its' liver.

The ideal is to create a biome. Ideally with crop rotation and green
(plant) manures we can create sustainable (or nearly sustainable)
agriculture.

In excess synthetic fertiliser AND natural ones will
both kill your plants in the same way. This does not mean that there
are no dissolved salts (as ions) in healthy soil nor does it mean that
you should never add such ions to your soil. You do it every time you
apply chicken manure or **** on the lemon tree.


--------
Very good point. Chem ferts can be used but we don't know the safe
dilution level. Maybe it's just me but I don't trust recommended dosages
because, I reason that they want you to use them up quickly and come
back for more.

This safe level stuff is just propaganda. You get the same ions out
of synthetics as "naturals" so why should we assume they behave any
differently. The problem with synthetics is that it is so much more
concenrated it is easier to overdose.

Did you see the excerpts from "Omnivore's Dilemma", footnoted with work
from the University of California at Davis stating that nitrogen from
chem ferts concentrated in leaves and attracted insects?

Secondly, if you do kill your microbes then you are
relaiant on the chem ferts to feed your plants. Now with ammonia, you
can smell it and a radical increase in the pH of the soil is apt to kill
your plants. So don't apply, if you can smell it.

Good thinking! But avoiding excess applies equally well to applying
synthetic ammonia as chook poo.

Also it (nitrogen) can
be safely added as protein. Microbes won't break it down if products
become toxic.

I don't know what you are getting at here. What protein would you add
to soil?

Dog hair for one and then there is the protein that make up the
micro-organisms.



It always seems the more we know, the less we know. I was surprised that
most of the books that I turned to to get some background on the
interaction between plants and soils, had very little information. It
was like I was looking for physiology and the books were giving me
anatomy.

Thanks for the questions because I think I have a better grasp of the
subject now.


There are good books out there on soil chemistry that are aimed at the
non technical person whcih are not just shills for chemical companies.

I thought that was my line? Anyway, the books I've seen so far tell
about soil composition and how to correct any faults. What I don't see
very often are books explaining the microbiology and their impact on
farming and gardening.

David

Got the second longest day of the year going on here. I'd better get out
and get me some. Have a Cooper's stout for me.
--
Billy
Coloribus gustibus non disputatum (mostly)

"Billy Rose" wrote in message
news:rosefam-6F2565.12481122062007@c-61-68-245-


The plastic clay underneath acts like a freaking huge sponge, it means
my pasture grows for months after rain as the clay slowly gives up the
water it absorbs during rain.
Well, not so much a sponge as a stopper. We call it hardpan. The water
can't go anywhere. Also makes it hard for trees to set tap roots and
find water, which then require watering.

This is not what I observe. The tree roots go right into it and once
established become much more drought proof. I also observe the sponge
behavour as do my neighbours who have been farming here for
generations.

Once again not necesarily. If you have sand-based soil you spend
you
life building it up with organic material to stop this happening but
with clay-based soil you don't, they hold most nutrients well.

So what your saying is that you've created an agricultural pot, the
sides and bottom of which is clay and that the nutrients that you put in
the pot, stay in the pot because the clay isn't permeable. RIght?


No. My amended gardens are all on top of the solid clay, I try to
never
bring it to the surface. The reason the amended soils hold nutrients
so we
is the colloids from the humus and the clay mixed into them.


Fertilizers are salts; they suck the water out of the
bacteria, fungi, protozoa, and_ nematodes in the soil.

In excess yes.

And I think that is what we are talking about. Excess. If you give the
micro-organisms the organic nutrients they need they will convert them
into the materials needed to create a web of life that supports the soil
and your plants. Where a large and diverse population of
micro-organisms can protect against non-benevolent micro-organisms.
I realize that you don't just use chem ferts but none of them support
the diverse population of organisms that make your soil fertile.
Otherwise you may as well go hydroponic.

We aren't trying to make a goose from Toulouse here, where you "cram" it
full of nutrient so that you can eat its' liver.

The ideal is to create a biome. Ideally with crop rotation and green
(plant) manures we can create sustainable (or nearly sustainable)
agriculture.


Agreed.

David

All right David,

I think you are due the following:
http://www.youtube.com/watch?v=2eMkt...elated&search= .

I wanted clean this up a bit as our discussion was getting spread out
and I'd like to keep it coherent.

My main contention is that chemical fertilizers may be used for crops
but they don't do anything for the soil ecology and, at worst, will
damage the soil, if used exclusively in place of organic fertilizers, or
if they are used in too high a concentration. A concentration of which
we are ignorant. We don't know what it is. Whereas, organically fed
soil, will support the thousands of different bacteria, fungi,
protoplast, nematodes, and earthworms that form the base of the soil
biome. These in a symbiotic relationship with the plants nurture each
other from their own niches. When the crops grow, they provide nutrient
for the micro-organisma. When they die, they provide more nutrient. When
the bacteria and fungi form alliance with the plants, they provide
nutrients for the plants. When the micro-organism dies, it provides more
nutrient for the plants. A win-win situation. Working together, they
create an inter-active ecology in which ever larger species can exist.

Perhaps there is a role for chem ferts, but I would have to think that
it would be limited.

Now, what I was woefully ignorant of was soil composition (30%-50% sand,
30%-50% silt, 20%-30% clay, and 5%-10% organic material. If this is
homogenized in you garden, you will have excellent soil. I was unaware
of the importance of clay and humus in binding nutrients, thanks for the
heads-up.

You seem to be proud of what you've accomplished with your growing beds.
Could you tell me your approach and maybe clear up my confusion to your
use of the word colloidal? Sand, silt, and clay represent a gradation of
inorganic material. Since the inorganic fraction is the largest fraction
of the garden, it must represent the continuous phase, whereas the
organic must be the dispersed phase.
--
Billy
Coloribus gustibus non disputatum (mostly)

On Jun 20, 2:44 am, "George.com" wrote:
"Billy Rose" wrote in message

...

This is most of the first chapter. Please offer critics. Right now, this
book (Teaming with Microbes) and "Omnivore's Dilemma" seem to give the
clearest sense of the direction that gardening and farming should be
going to get us off the dependancy on petroleum based pesticides and
fertilizers.
Hi folks,

I am the author of teaming with microbes. I hope you all enjoy it. In
fact, if you buy it and really don't like it, contact me and I will
refund your money......Just wanted you to know that If you have a
first printing edition, there is a mistake on pages 41 & 42....re
pH....the higher the pH the more alkaline the soil...the lower the pH,
the more acidic. If you have few hydrogen ions, the pH is
high.....etc.

Anyhow, this has been corrected in the second printing edition.

If you have questions, or want a speaker etc, you can contact me off
list....I do weddings and Bar Mitvahs....anywhere there are gardeners~

Cheers,

Jeff Lowenfels
Anchorage, Alaska



Again, thank to whoever turned me on to this book.

Teaming with Microbes by Jeff Lowenfels and Wayne Lewis

Chapter 1

What Is the Soil Food Web and
Why Should Gardeners Care?

thats good stuff Billy, thanks for sharing it. One resource I found really
interesting & helpful was a guide to organic pastoralism. It really started
me down a different path. It is free to downloadhttp://www.biodynamic.org.nz/guides/intro_ch1.pdf

rob

In article . com,
wrote:

Hi folks,

I am the author of teaming with microbes. I hope you all enjoy it. In
fact, if you buy it and really don't like it, contact me and I will
refund your money......Just wanted you to know that If you have a
first printing edition, there is a mistake on pages 41 & 42....re
pH....the higher the pH the more alkaline the soil...the lower the pH,
the more acidic. If you have few hydrogen ions, the pH is
high.....etc.

Anyhow, this has been corrected in the second printing edition.

If you have questions, or want a speaker etc, you can contact me off
list....I do weddings and Bar Mitvahs....anywhere there are gardeners~

Cheers,

Jeff Lowenfels
Anchorage, Alaska

Specifically,

1) Page 41, Soil pH, starting with the end of the second line:
" If you have relatively few hydrogen ions compared to the rest of what
is in solution, the pH is low and the solution is acidic."

This is an error. High concentrations of (H+ or H3O+: hydronium ions)
make the solution acidic.

The pH measures the concentration of (H+ or H3O+: hydronium ions) in the
solution. 1^E-1 is larger than 1^E-14. The -1 and the -14 are made
positive by convention. pH1 is strongly acidic and pH 14 strongly basic.
Because pH 14 is so basic, there are very few hydronium ions floating
around.

2) Then third line up from the bottom of p. 41:
As the concentration of H+ goes up, the pH goes up-the soil is
increasingly alkaline.
It should read, "As the concentration of H+ goes up, the pH goes
down-the soil is increasingly acidic

3) Then first line, first sentence p.42:
Adding OH to the solution lowers the pH (that is, soil is increasingly
acidic) because it lowers the concentration of H+.
It should read, "Adding OH to the solution raises the pH (that is, soil
is increasingly basic) because it lowers the concentration of H+."

Other than that snafu on the first edition the rest seems fine.
Presently I'm reading a first edition from the library but I plan on
buying the second.
--
Billy
Coloribus gustibus non disputatum (mostly)