Xref: kermit rec.gardens:285569

Hello Wong,

"nswong" wrote in news:2kou3bF4ttfeU1@uni-
berlin.de:

Adding carbon will quite possibly detract from the amount of
N available to a plant. .

It depend on the carbon are in what form. If it's sugar or starch, it
do. If it's lignin or cellulose, the effect should be unnoticeable.
Newspaper are compose mostly by cellulose.

As I understand it, for optimal decomposition, you should have a C/N
ratio of 30:1. I have read that wood chips and sawdust will reduce
nitrogen availability during decomposition when used as mulch or in a
compost pile, and I assumed that was because of the high carbon content.
Newspaper has approximately between 1/2x and 5x the carbon of sawdust
(both primarily celluose).

[1] http://compost.css.cornell.edu/calc/lignin.html

Adding N to compensate will degrade the weed blocking utility of the
newspaper as decomposition accelerates

Adding N will not always speed up the decompostion. It really depend
on situation.

hmm, according to [1], you are right, at least for lignin decomposition.
A certain quantity of additional nitrogen will speed up anaerobic
decomposition, but excess has little or no effect. It does not say about
cellulose.

Mulch supress weeds not just because the physical blocking ability, it
can also leach out some chemical harm weeds. Critters in mulch will
also help to supress weeds.

Yes and also fungi.

But to me, I will never add N to the mulch

My point is if you wanted to increase nitrogen availability to the soil
to compensate for newspaper decomposition loss (if there actually is any)
you could add to the soil, but actually if you wanted newspaper for
nutrients (as opposed to weed control), you should probably do that in
the compost pile and not in the flower bed.

Also, correct me if I'm wrong, but I assume carbon is of limited value
as a nutrient amendment, as plants (primarily?) obtain carbon from
atmospheric carbon dioxide during photosynthesis. At any rate, plants
do *excrete* carbon from their roots after periods of elevated carbon
dioxide[2].

However, I'll concede that the newspaper and newspaper debris may have
indirect and significant benefits (functioning similarly to deciduous
leaf litter) in providing habitat and food for beneficial insects and
microbes and enhancing soil structure.

Yes, here the soil amendment I'm refer to improve soil structure.

While not directly contributing materiel, it is possible that
landscape fabric made of polyester (and perhaps also polypropylene)
can fixate minor amounts of atmospheric nitrogen via wind action and
electrostatic effect[3].

I believe N fixed by bacterial using carbon as energy in orgainc mulch
will do a better job.

I agree, the amount of nitrogen fixated (if any) by electrostatic effect
over a surface is probably minor, but I mention it because occasionally
you hear about people growing huge tomatoes with panty hose (nylon) and
the effect may be similar.

Yes, newspapers need to be replaced often compared to landscape
fabric. To me, this is not an advantage in permanent or semi-permanent
installations.

For this I do facing problem to explain my view. In bussiness, we talk
about total cost of ownership. In here we talk about in the total life
span of the product, how much cost involve and how much the return
get.

In these terms, landscape fabric is USD$10 / 150 sq. ft (14 sq. meter),
with a life span of 15 years when installed properly, plus the starting
cost of mulch, USD$2-3 / 3 cubic feet (for large pine bark nuggets) at
recommended coverage rate of 4-6 inches (10-15 cm, mine is probably less
than 2 inches) and periodic replacement cost for wind or decomposition
loss. Other factors: labor savings in amount of time spent weeding,
labor increase in adding amendments, productivity comparisons if
relevant, etc. My recommendation is based on use for a home flower bed,
not a large scale or intensive operation.

For this, I'm not know enough to provide a view. Sorry about that.

[1] http://ianrpubs.unl.edu/horticulture/g810.htm "Table I.
Carbon/Nitrogen Ratios of Some Common Organic Materials"
[2] http://www.co2science.org/subject/r/summaries/roots.htm [3]
http://www.ce-mag.com/archive/02/Spring/chubb.html "Findings"

Thanks for the links, I will look at it later. :-)

Newspapers will not block nightcrawler(earthworm) from pulling plant
debris to their tunnel as their food.
Landscape fabric will, I don't think you will find much earthworm
under the landscape fabric.

Unless nightcrawlers will chew a hole through newspaper to open their
covered burrow (quite possibly true), unbroken newspaper is as much a
barrier as landscape fabric. But assuming a population rate of 1-7
worms per square meter[4] there should be sufficient openings in a
typical fabric installation such that the population is not impacted
significantly (assuming there is no reason why they would not choose
to use an available opening). Shallow burrowing earthworms do not
share nightcrawler feeding habit, but may exit their wandering burrows
during extensive rain[5].

[4] http://www.swcs.org/t_pubs_journal_2...acts_water.htm [5]
http://www.ces.purdue.edu/extmedia/AY/AY-279.html

Unless nightcrawlers will chew a hole through newspaper to open their
covered burrow (quite possibly true)

A few sheet of newspaper will not block earthworm.

In my experience, earthworms (not necessarily nightcrawlers) will
continue to crawl until it finds an existing opening and not attempt to
chew through paper to find an exit. In this way, I assume it is similar
to fabric, although there is no way the earthworm will be able to chew
through landscape fabric. These observations were in daylight, so may
not be representative of normal behaviour.

But assuming a population rate of 1-7 worms
per square meter[4] there should be sufficient openings in a typical
fabric installation such that the population is not impacted
significantly (assuming there is no reason why they would not choose
to use an available opening). Shallow burrowing earthworms do not
share nightcrawler feeding habit, but may exit their wandering burrows
during extensive rain[5].

I'm quite sure landscape fabric significantly reduce earthworm
population.

Okay.

Newspapers will not block air and water to the soil, since they
decompose quickly.
Landscape fabric may, after sometime the holes may blocked by roots.

Newspapers will block water to the soil or at the minimum cause
pooling until drainage hole(s) are formed, which will not necessarily
be uniformly distributed. Landscape fabric is semi-porous or porous
to both air and water, as are roots. The mulch is more likely to
block water than the fabric.

Look at all short of filter we use, they all block. Do a test, remove
the mulch on top of your landscape fabric, put some water on top of
it, see how long it will pass through.

I do not think this is a problem. When it rains, I do not have a problem
with drainage, so the water must go down some where, even if the gutters
are removed (and rain falls directly from the roof to the flower bed).
If you test the fabric by itself, fast moving water (such as from a
faucet) will be deflected from the surface, but slow water (as typical
with mulch impeded flow) will drain. If it weren't porous, you might as
well just you regular black polyethylene sheeting.

Mulch have critters making tunnel in it, except there is little
critter in it.

I could be wrong, but I just don't see macroscopic organisms eating
vertical holes through newspaper to gain surface access.

Newspapers: For adding soil amendment(carbon/organic matter), just
spread it on top of organic mulch(newspaper/manure/leaf...),
eventurely it will find it way to soil by critters. Landscape
fabric: Had to put it under the landscape fabric, or else only
nutrient will pass through the landscape fabric in liquid form, but
not much of organic matter.

Correct, although the fabric will not necessarily pass the suspended
nutrients, depending on the size of the pores in the fabric.

I'm refer to those nutrien that resolve in water as liquid form.

You mean nutrients that are dissolved in water? It is possible that the
fabric (different kinds of fabric vary) will filter the dissolved
nutrients (in the same way a paper coffee filter may filter salt from
seawater). I do not know, so I would not rely on it.

Newspapers: When weeds find the way through the old newspaper/mulch,
just put new newspaper/mulch on top of weeds. Done! Landscape
fabric: Do you ever think of putting new landscape fabric on top of
old landscape fabric? ;-)

Weeds other than certain monocotyledons will not find their way
through landscape fabric from below. If a plants attempts to colonize
the top of the fabric, it is easily picked off. Done! No need to dig
or look for a newspaper stand.

Landscape fabric is not overlayed because it is not necessary.
However, if you have made a hole in the fabric that you do not want,
it can be repaired by simply putting a new piece on top (or tucked
below the existing fabric).

No comment. g

Newspapers: Never need to replace, just adding new one.
Landscape fabric: It's a nightmare to replace a landscape fabric
that have plant root grow into it.

Landscape fabric: Never need to replace. Period. Okay, not in 5-15
years at least. Landscape fabric can become embeded with roots
attempting to penetrate from below, but the removal of such fabric is
of minor difficulty. Removing stripable wallpaper takes more effort.

Landscape fabric: Never need to replace. Period. Okay, not in 5-15
years at least.

From what I read, if landscape fabric are expose to sun, will not last
long.

Yes, this is printed on the product labeling. However, I have some
exposed pieces (DuPont Weed Control Fabric, rugged spunbonded
polypropylene, UPC 0 83014 20163 2) outside and after more than a year,
visually they all look the same as pieces that were stored in the
original bag in the garage. (I did not look at them under a microscope.)
The degradation rate probably differs in Canada and Singapore. (Not the
same product as used in my front yard, which is similar to but not
EasyGardener Weedblock.)

Landscape fabric can become embeded with roots attempting to penetrate
from below, but the removal of such fabric is of minor difficulty.

From what I read, those user of landscape fabric donot take it as
"minor difficulty". g

haha, perhaps the Green lacking in my Thumb is made up with my Incredible
Hulk strength.

Will I be able to cover a large area (such as 10-ft x 6-ft)

Using a sickle to cut what(weeds) above the mulch, leave it there,
add some new mulch. I can cover 50-ft x 5-ft within one hour, and
it can last for two months. Don't afraid of walking on the mulch,
this will not really compact the soil, walk on bare soil are another
story.

Landscape fabric is a long term installation and will take more time
for planning and preparation. The actual installation is simple.

No comment. g

Sorry, I'm getting a bit impatience. :-(

No comment. :-)