"nswong" wrote in news:2lo7pjFfd8kmU1@uni-
berlin.de:

"Salty Thumb" wrote in message
...

This is my point, it's the carbon available to bacterial, not the
actual amount of carbon that causing temperary N deficiency.

If the carbon do in a slow release form for bacterial, it will not
cause a suddent bacterial bloom even there is a lot of carbon there.

I'm not sure what you mean by this. The carbon in cellulose is not
going to be released in any significant quantitiy without bacterial
action. The bacteria will not have action without also N being
present. When both are present the bacteria will use both the N and C,
making less N available for plants. [I don't know what happens to the
N after the bacteria get it (it has to go somewhere)]. Regardless,
bacteria will not be able to decompose diamonds.

I'm not sure what you mean by this.

If the carbon do in a slow release form for bacterial,

Think about fertilizer, there is water soluble and slow release. I
believe carbon do so. I believe sugar and starch are water soluble,
cellulose and lignin are slow release.

okay, sure, I can go along with the concept that carbon locked in
cellulose and lignin usually do not as easily participate in reactions as
other forms.

it will not
cause a suddent bacterial bloom even there is a lot of carbon there.

For a fertilizer, it will causing root burn or not does not really
relate to the amount of element it contain. With the same content of
element, a water soluble fertilizer will surely having bigger chance
to cause root burn than a slow release fertilizer.

okay

Let say there are total carbon enough to construct 1000 bacterial, but
If the carbon make availble(release) in any bacterial life cycle are
just enough to maintain 10 bacterial, no more than 10 bacterial will
coexist at any given time period.

I think the difference between slow release fertilizers and cellulose is
that the coatings on slow release fertilizers are designed to degrade
mechanically or chemically (wind/water action, soil chemistry or natural
instability) and not by biological effect. The speed at which cellulose
decays can be accelerated or decelerated by the presence or absense of
nitrogen (and water). I don't think that is true of slow release
fertilizers. So while wood is usually a 'slow release form', with the
addition of nitrogen in a biologically active situation it ceases to be
'slow release'. Similar degradation does not occur with the fertilizers
in the time scale of normal (non-compost) bed, because quite frankly,
normal bacteria don't have much to gain by decomposing artifical
fertilizer pellets. To put another way, if the carbon is milk and
nitrogen is cookies, when the bacteria see the two together, they are
going to eat regardless of any ideas about 'slow release'.
..
The carbon in cellulose is not going to be released in any significant
quantitiy without bacterial action.

IIRC, a lot of the form of carbon can be change to
available form by enzyme, and there is also a lot of the life form do
secrete these enzyme. If I'm not wrong, when those carbon in
unavailble form pass through the earthworm digesting system, the
enzyme secrete by earthworm do convert them to available form for
bacterial. Fungus do secrete enzyme too.

I think this is still dependent on the presense of nitrogen to make
proteins with energy supplied from the carbons.

Oxidization also will turn it to plant available form. g

Both newspaper and sawdust have high cellulose percentage. Sawdust
is reported to reduce nitrogen availability when used in a compost
pile.

I believe that is starch and sugar in the sawdust that cause this,
not cellulose or lignin. I believe newspaper do lost some of it
starch and sugar while in the process.

Cellulose is made from repeating units of glucose (a simple sugar)
[1]. Starch is also made from glucose [2]. So unless there is some
other form of sugar you are thinking of, I don't think so.

I do come across the explanation before, but it's too technical for
me, so I just skip that part.

My explanation a
Put one part of flour in ten part of water in a container, stir it.
Put one part of newspaper in ten part of water in another container,
stir it also. You will see the different. g

Okay, but I'm not saying the starch in flour isn't different from the
cellulose in newspaper. I'm saying newspaper and sawdust probably have
similar nitrogen leaching effects due to the cellulose content. Do the
same experiment with sawdust and compare to the flour. Even if you shred
the newspaper or stick it in a blender, I think you will find them both
more similar to each other than to the flour.

[1] http://www.psrc.usm.edu/macrog/cell.htm [2]
http://www.poco.phy.cam.ac.uk/resear...rch/whatis.htm

Thanks for the links. I do hope it's something that easy to
understand. ;-)

"AY-279 Earthworms and Crop Management"
I personally think this earthworm article as the best I read in
website are because it's something easy to understand for me, not
because it's the one that go to the most detail.

So, either mulch will cause temporary N deficiency or not will
depend on the C/N ratio make available by rain to soil bacterial.

I will say that, some mulch will and some mulch will not causing
temporary N deficiency. It will depend on the amount of the C and N
available to bacterial that do bring to soil by rain water.

What I try to say a Put a KG of flour as mulch to one plant. Put a
KG of cotton as mulch to another plant. Sprinkle some amount of
water(rain) on top of both "mulch", and see which plant leaves will
turn to yellow due to the carbon bring down by water from mulch.

I think yellow leaves are a sign of nitrogen deficiency. My explanation
is the soil organisms are using the nitrogen and the very accessible
carbon in the flour (which also easily washes down into the soil). So
it's not really the carbon, it's the hungry soil organisms that see the
carbon but also need nitrogen to digest it, leaving little nitrogen for
plants and then the leaves turn yellow. The plant may also not like some
of the gluten in the flour. The cotton is cellulose and less accessible
than flour, but that doesn't mean it wont't cause some nitrogen
deficiency by intercepting nitrogen that would normally wash through the
soil.

If you have high N, some of that N will be used by decomposers leaving
X amount for the plants, which still might lead to low N. If your top
layer is biologically active, then most of N from rain will be
intercepted before it reaches the plant roots.

Maximum number of life form are limited by resource, it included
space, water, air, and other element. The one that lack of will become
the factor of constrain, and those resource that is abundance remain
as abundance.

When a life form are in bloom, other life form depend on this life
form also will increase in number and put this life form in check. We
call this as predator, the poo of this predator mostly in a form that
can use by plant.

Iife form convert N from one form to another form. Man eat plant get
protein give ammonia. Man cannot digest ammonia, that is convert to by
man. An bacteria convert nitrite to nitrate will not take in nitrate

Some bacteria convert the ammonia to nitrite, some bacteria convert
nitrite to nitrate, plant convert nitrate to protein.

So "if my top layer is biologically active", each life form will hold
N in one form for a period, and act as a nutrient bank, at the end
make it slowly release to the plant.

yea, but not all forms of nutrients are exclusive, the set of resources
required by bacteria is less than that of plants, so it is less likely
that deficiency in one will limit the population. (For example bacteria
may only need C, N, H20, and plants need H20, CO2, N, Fe, P, K, so
limiting Fe will not limit bacterial population, but will limit plant
population). Also, discounting the presence of legumes, your plants are
not going to have a nitrogen generating source below the soil. The
nitrogen will wash down from above and the bacteria in the top layer will
have first access.

When weed go through the mulch:

In my case of not using newspaper, I will use sickle or handheld
string trimmer cut off the weed part that on top of mulch, on top of
the weed debris, add some more mulch. This will last about two month.

Using newspaper, I will simply laydown the newspaper on top of the
weed, add some more mulch. I believe it will last more than two month.

BTW: Weed here grow quite fast, today I cut it to the ground, next day
it can grow up to one and half inches. Weeding without mulch are not
the way to go.

If I were in your situation, I would probably do the same + the living
mulch or cover crop you mentioned earlier. The only difference is I may
worry about weeds resprouting from roots, so I may dig them out instead
of cutting them if it is not too time consuming. Maybe also some
research into plants that are alleopathic to the weeds.