In acid soil and peat what are the acids that make it so?
Carbonic? a bit weak perhaps?
Nitric?
Wouldn't be Sulphuric.
Can't believe it would be Hydrochloric.
Any ideas, and where would it come from.
Don

In article ,
"Donwill" popple @diddle .dot writes:
| In acid soil and peat what are the acids that make it so?
| Carbonic? a bit weak perhaps?
| Nitric?
| Wouldn't be Sulphuric.
| Can't believe it would be Hydrochloric.
| Any ideas, and where would it come from.

There are a zillion common organic acids, including acetic, lactic,
malic, citric, ascorbic and tartaric. But my understanding is that
soil acidity isn't as simple as that.


Regards,
Nick Maclaren.

"Donwill" wrote
In acid soil and peat what are the acids that make it so?
Carbonic? a bit weak perhaps?
Nitric?
Wouldn't be Sulphuric.
Can't believe it would be Hydrochloric.
Any ideas, and where would it come from.

Not quite that simple, see...

http://en.wikipedia.org/wiki/Soil_pH

--
Regards
Bob Hobden

Donwill wrote:
In acid soil and peat what are the acids that make it so?
Carbonic? a bit weak perhaps?
Nitric?
Wouldn't be Sulphuric.
Can't believe it would be Hydrochloric.
Any ideas, and where would it come from.
Don


Ex Chemistry Teacher mode - Humus contains of many macromolecules with
carboxylic acid groups. (also phenolic but those would be less acidic).
However with a complicated system like soil with ions being added and
leached away all the time it is not really possible to say that the
hydrogen ions that make it acidic come from a particular acid.

Paul

--
CTC Right to Ride Rep. for Richmond upon Thames

Chris Hogg wrote:
On Fri, 14 Mar 2008 17:38:48 -0000, "Donwill" popple @diddle .dot
wrote:

In acid soil and peat what are the acids that make it so?
Carbonic? a bit weak perhaps?
Nitric?
Wouldn't be Sulphuric.
Can't believe it would be Hydrochloric.
Any ideas, and where would it come from.
Don

The commonest soil acids are humic acid and fulvic acid. These are
organic acids with very complex structures, unlike some of the more
familiar organic acids such as acetic acid (vinegar) or fatty acids
such as cooking oils. They derive from decaying vegetable matter. Soil
scientists have studied them for years to try and understand their
structures, but AFAIK haven't come up with definitive results yet,
simply because the structures are so complex.

Humic acid can be extracted from peat, for example, by stirring it in
water with a few spoonfuls of baking soda to make it alkaline, and
letting it stand for a few days. Drain off the brown water that
results and add some vinegar or other acid to neutralise any remaining
baking soda, and a voluminous yellow-brown jelly-like mass will form.
This is 'pure' humic acid.

See also http://en.wikipedia.org/wiki/Humic_acid
and http://www.thekrib.com/Chemistry/humic.html


Humic acid was on sale at my local garden centre as a "soil
conditioner". Looks like coal dust and appears to be insoluble in water.
I read somewhere that it occurs naturally above coal deposits in parts
of the U.S. and Australia.

Chris Hogg wrote:
On Sat, 15 Mar 2008 17:53:24 GMT, Stuart Noble
wrote:

Chris Hogg wrote:
On Fri, 14 Mar 2008 17:38:48 -0000, "Donwill" popple @diddle .dot
wrote:

In acid soil and peat what are the acids that make it so?
Carbonic? a bit weak perhaps?
Nitric?
Wouldn't be Sulphuric.
Can't believe it would be Hydrochloric.
Any ideas, and where would it come from.
Don

The commonest soil acids are humic acid and fulvic acid. These are
organic acids with very complex structures, unlike some of the more
familiar organic acids such as acetic acid (vinegar) or fatty acids
such as cooking oils. They derive from decaying vegetable matter. Soil
scientists have studied them for years to try and understand their
structures, but AFAIK haven't come up with definitive results yet,
simply because the structures are so complex.

Humic acid can be extracted from peat, for example, by stirring it in
water with a few spoonfuls of baking soda to make it alkaline, and
letting it stand for a few days. Drain off the brown water that
results and add some vinegar or other acid to neutralise any remaining
baking soda, and a voluminous yellow-brown jelly-like mass will form.
This is 'pure' humic acid.

See also http://en.wikipedia.org/wiki/Humic_acid
and http://www.thekrib.com/Chemistry/humic.html

Humic acid was on sale at my local garden centre as a "soil
conditioner". Looks like coal dust and appears to be insoluble in water.
I read somewhere that it occurs naturally above coal deposits in parts
of the U.S. and Australia.

Lignite (soft coal, brown coal) is often rich in humic acids and is
sometimes processed commercially to extract the alkali-soluble
components in a manner much as I described above. The products are
used as protective colloids and dispersants for clays in a variety of
applications. There's a lot of lignite associated with ball clay
deposits in South Devon, but AFAIK it's not processed to extract the
humic acids. Kassel, in Germany, was at one time a well-known source
of lignite extracts.

But I doubt that what you've seen is the extracted material. Most
probably it's the lignite itself. Whether it has any beneficial
effects on soil in that form, I don't know, but I would guess it would
take years to break down and release the humic acids onto the mineral
particles in the soil, which is where it's needed. After all, the
lignite in South Devon has been in the ground for some 20 million
years, and has become pretty stable and inert over that time.


Yes, I did wonder about that. I guess the purveyors of humic acid are
banking on an alkaline soil. There seems to be a lot of controversy over
whether potassium or ammonium humates are beneficial.
Interesting that Kassel Brown is a recognised dye in the art world.

In article ,
Stuart Noble writes:
| Chris Hogg wrote:
|
| But I doubt that what you've seen is the extracted material. Most
| probably it's the lignite itself. Whether it has any beneficial
| effects on soil in that form, I don't know, but I would guess it would
| take years to break down and release the humic acids onto the mineral
| particles in the soil, which is where it's needed. After all, the
| lignite in South Devon has been in the ground for some 20 million
| years, and has become pretty stable and inert over that time.
|
| Yes, I did wonder about that. I guess the purveyors of humic acid are
| banking on an alkaline soil. There seems to be a lot of controversy over
| whether potassium or ammonium humates are beneficial.

The key to that is whether it is in the bioactive level of the soil
or not. Even peat is stable when below the water table, and degrades
very slowly if below the bioactive level. It was the use of the Fens
for farmland that caused and is causing the oxidisation of the peat.
There isn't a hard and fast boundary between peat and anthracite,
and my understanding is that the term lignite covers a wide range!

So it will depend on how lignified the lignite is :-)


Regards,
Nick Maclaren.