In article ,
Franz Heymann wrote:
"Jaques d'Altrades" wrote in message
...

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is acidic.other
than old batteries?

Iron. The issue of "acidity" in soil is not what you would expect
from O-level chemistry.


Regards,
Nick Maclaren.

"Nick Maclaren" wrote in message
...
In article ,
Franz Heymann wrote:
"Jaques d'Altrades" wrote in message
...

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Iron. The issue of "acidity" in soil is not what you would expect
from O-level chemistry.

I beg to differ. The definition of acidity as being measured by the
hydrogen ion concentration is applicable universally. It refers to an
excess of hydrogen ions. any of the substances in a scrapyard can increase
the concentration of hydrogen ions in the soil, then it will acidify it. If
not, it won't. So which substance commonly found in a scrapyard has this
property? I am asking this as a genuine question.

Franz

The message
from "Franz Heymann" contains these words:

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is acidic.other
than old batteries?

Isn't old batteries good enough?

If not, then think 'rust'.

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm

On Sat, 4 Oct 2003 00:19:32 +0100, Jaques d'Altrades
wrote:

The message
from "Franz Heymann" contains these words:

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is acidic.other
than old batteries?

Isn't old batteries good enough?

old battery hens? :-(
--
Martin

"Jaques d'Altrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Isn't old batteries good enough?

If not, then think 'rust'.

My undersdtanding of rust is that it consists of lose flakes of a hydrated
iron oxide. I may be blind, but I don't see where the hydrogen ions come
from in that substance.

Franz

Franz

In article ,
Franz Heymann wrote:

"Jaques d'Altrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Isn't old batteries good enough?

If not, then think 'rust'.

My undersdtanding of rust is that it consists of lose flakes of a hydrated
iron oxide. I may be blind, but I don't see where the hydrogen ions come
from in that substance.

Nor do I, but I stopped doing chemistry at O-level. I can assure
you that the matter of soil acidity is NOT a simple matter of acid
versus base, and that things like rusting iron can affect it
considerably. But I can't tell you why or how.

There is also the point that a lot of calcifuge plants are actually
just incapable of taking up iron in an alkaline environment, and so
adding iron deals with their problem.


Regards,
Nick Maclaren.

"Nick Maclaren" wrote in message
...
In article ,
Franz Heymann wrote:

"Jaques d'Altrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

Increasing the pH of a soil is very much easier than decreasing
it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Isn't old batteries good enough?

If not, then think 'rust'.

My undersdtanding of rust is that it consists of lose flakes of a
hydrated
iron oxide. I may be blind, but I don't see where the hydrogen ions come
from in that substance.

Nor do I, but I stopped doing chemistry at O-level. I can assure
you that the matter of soil acidity is NOT a simple matter of acid
versus base, and that things like rusting iron can affect it
considerably. But I can't tell you why or how.

I am quite aware of how acidity is defined and measured.
If you think iron rust ca-n affect the pH of the soil, please say how ot
does it, and don't just continue saying that "rusting iron can affect the
acidity of the soil".

In one corner of my garden there are the rusty remnants of an old
incinerator. They have been there for ten years or so, and there s a lot of
rust lying around on the soil there. I have measured the pH of a soil
sample at that position, and as best I can measure, it is no different from
the pH of a sample taken about 15 ft from there.

There is also the point that a lot of calcifuge plants are actually
just incapable of taking up iron in an alkaline environment, and so
adding iron deals with their problem.

That is a *very*, *very*, *very* different matter. In that case, the reason
is not that the iron acidifies the soil, but simply that you are overloading
the soil so much with the desired iron ion that the plants can have a feast
of it before the chemical reactions in the soil have converted it all to the
undesired ion. One of them is a ferric ion and the other is a ferrous ion,
but I cannot remember which is which. Perhaps some urgler can remind us.

Franz

The message
from "Franz Heymann" contains these words:


"Nick Maclaren" wrote in message
...
In article ,
Franz Heymann wrote:
"Jaques d'Altrades" wrote in message
...

Increasing the pH of a soil is very much easier than decreasing it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Iron.

/\/\/\/\/\

The issue of "acidity" in soil is not what you would expect
from O-level chemistry.

I beg to differ. The definition of acidity as being measured by the
hydrogen ion concentration is applicable universally. It refers to an
excess of hydrogen ions. any of the substances in a scrapyard can increase
the concentration of hydrogen ions in the soil, then it will acidify it. If
not, it won't. So which substance commonly found in a scrapyard has this
property? I am asking this as a genuine question.

Rusty iron. Would you like to ask the question once more for good luck?

:-)

Janet.

"Janet Baraclough" wrote in message
...
The message
from "Franz Heymann" contains these
words:


"Nick Maclaren" wrote in message
...
In article ,
Franz Heymann wrote:
"Jaques d'Altrades" wrote in message
...

Increasing the pH of a soil is very much easier than decreasing
it.

Except in a big scrapyard......

You know something I don't. What is it in a scrapyard which is
acidic.other
than old batteries?

Iron.

/\/\/\/\/\

The issue of "acidity" in soil is not what you would expect
from O-level chemistry.

I beg to differ. The definition of acidity as being measured by the
hydrogen ion concentration is applicable universally. It refers to an
excess of hydrogen ions. any of the substances in a scrapyard can
increase
the concentration of hydrogen ions in the soil, then it will acidify it.
If
not, it won't. So which substance commonly found in a scrapyard has
this
property? I am asking this as a genuine question.

Rusty iron. Would you like to ask the question once more for good luck?

No, but I will ask a complementary question, which I have also askes
elsewhere. Where do the hydrogen ions come from in rust, which is a
hydrated oxide of iron?

Franz

The message
from "Franz Heymann" contains these words:

No, but I will ask a complementary question, which I have also askes
elsewhere. Where do the hydrogen ions come from in rust, which is a
hydrated oxide of iron?

Rust is acted upon by a number of chemicals in the soil, notably
carbonic acid. Iron has a multitude of valencies and can be
electropositive and electronegative, depending on available ions with
which to bond, and in the electronegative incarnation forming the
(notional) ferric acid H2FeO4, so there are acidic ferric ions active in
the soil.

HTH

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm

In article ,
Franz Heymann wrote:

My undersdtanding of rust is that it consists of lose flakes of a
hydrated
iron oxide. I may be blind, but I don't see where the hydrogen ions come
from in that substance.

Nor do I, but I stopped doing chemistry at O-level. I can assure
you that the matter of soil acidity is NOT a simple matter of acid
versus base, and that things like rusting iron can affect it
considerably. But I can't tell you why or how.

I am quite aware of how acidity is defined and measured.
If you think iron rust ca-n affect the pH of the soil, please say how ot
does it, and don't just continue saying that "rusting iron can affect the
acidity of the soil".

Please reread what I posted, and do me the courtesy of believing that
I meant it - I DON'T KNOW.

I can tell you suitable keywords to chase it up, but the chemistry
and biochemistry of such things is WAY beyond my knowledge. One
suitable keyword is "buffering", which is not directly relevant but
is a related concept. I can give you a NAIVE explanation of why
iron increases acidity, but I am 90% certain that it is misleading.

Iron is higher than hydrogen on the electrochemical scale, and so
will tend to displace the latter from complex salts, leaving the
hydrogen in simpler compounds. As the acidity of compounds is not
a DIRECT function of whether there is an ionic hydrogen bond, it is
very likely that this will cause two essentially neutral substances
(the original compound and iron) to turn into an essentially neutral
one (the iron compound) and an acid.

Also, due to the effect of bacteria and other reactions in changing
the various chemicals, the acidity of soil as seen by plants and that
as measured by a simplistic test may not be the same. This factor
is very relevant to the release of ammonia, but I don't understand
how that works, either.


Regards,
Nick Maclaren.

"Jaques d'Altrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

No, but I will ask a complementary question, which I have also askes
elsewhere. Where do the hydrogen ions come from in rust, which is a
hydrated oxide of iron?

Rust is acted upon by a number of chemicals in the soil, notably
carbonic acid. Iron has a multitude of valencies and can be
electropositive and electronegative, depending on available ions with
which to bond, and in the electronegative incarnation forming the
(notional) ferric acid H2FeO4, so there are acidic ferric ions active in
the soil.

The only iron ions of which I know are Fe++ and Fe+++ ions, and extremely
rarely Fe++++ and Fe++++++
From ignorance I ask what these electronegative and electropositive
incarnations of iron are of which you speak? All these ions I listed are
positive ions.

OH, I might be beginning to see the light: If there is such an ion as
(FeO4)-- then there could be compound
H++(FeO4)-- which could ionise in water to give the hydrogen ions required
to lower the pH. Is that what you are trying to say?

Franz

The message
from "Franz Heymann" contains these words:
"Jaques d'Altrades" wrote in message
...

Rust is acted upon by a number of chemicals in the soil, notably
carbonic acid. Iron has a multitude of valencies and can be
electropositive and electronegative, depending on available ions with
which to bond, and in the electronegative incarnation forming the
(notional) ferric acid H2FeO4, so there are acidic ferric ions active in
the soil.

The only iron ions of which I know are Fe++ and Fe+++ ions, and extremely
rarely Fe++++ and Fe++++++
From ignorance I ask what these electronegative and electropositive
incarnations of iron are of which you speak? All these ions I listed are
positive ions.

OH, I might be beginning to see the light: If there is such an ion as
(FeO4)-- then there could be compound
H++(FeO4)-- which could ionise in water to give the hydrogen ions required
to lower the pH. Is that what you are trying to say?

I can think of FeO, FeO2, Fe2O3, Fe3O5 off the cuff, and I have a
nagging suspicion that there's one other oxide of iron at least.

While Ferric acid is only notional, various ferrites are found
naturally. So, FeO2 at least is capable of becoming an electronegative
ion in the right conditions, which presumably is how it becomes
sequesterd in some alkaline soils.

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm

[ A large amount of O-level chemistry snipped. ]

Whether or not that is so, it is very likely irrelevant. The issue
can be seen most clearly in the souring of milk. A nearly neutral
substance turns acid with nothing added or lost.

Another example of a thoroughly counter-intuitive substance is the
way that magnesium can affect acidity. Magnesium sulphate (neutral)
is used in brewing to make the water slightly acid, and magnesium
carbonate (slightly alkaline) has an acid-like effect on plants.
The former effect CAN be explained in terms of O-level chemistry,
could I remember it :-)

It is very, very unlikely that the way that iron causes soil to turn
acid can be explained in terms of O-level chemistry, given the
extremely complex biochemistry of soil.


Regards,
Nick Maclaren.

"Nick Maclaren" wrote in message
...
[ A large amount of O-level chemistry snipped. ]

Whether or not that is so, it is very likely irrelevant. The issue
can be seen most clearly in the souring of milk. A nearly neutral
substance turns acid with nothing added or lost.

Another example of a thoroughly counter-intuitive substance is the
way that magnesium can affect acidity. Magnesium sulphate (neutral)
is used in brewing to make the water slightly acid, and magnesium
carbonate (slightly alkaline) has an acid-like effect on plants.
The former effect CAN be explained in terms of O-level chemistry,
could I remember it :-)


It is very, very unlikely that the way that iron causes soil to turn
acid can be explained in terms of O-level chemistry, given the
extremely complex biochemistry of soil.

If iron, which is easily available in the form of scrap, is capable of
acidifying soil, why is it that I found 5 references which mention that the
only realistic way of acidifying soil is the addition of large quantities of
sulphur, and none which mention anything about iron being used for this
purpose?

I have related in this thread that the soil in my garden in a place where
there is a
lot of rust from an ancient inicinerator has the same pH as that at a
position far away from this source of iron. Please explain.

Franz


Regards,
Nick Maclaren.