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.
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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.
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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.
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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.
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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.
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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).
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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.
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Sounds right to me. So we are talking NH3 + H2O --- NH4 + OH. The
equilibrium will still be far to the left.
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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.
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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?
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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.
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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.
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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.
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First line below. Fetilizers are salts. They separate into cations and
anions, creating osmotic pressure that kills the microbes.
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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)