Hi All,

This is the best article about earthworm I read before on a
website(forgotted where I read already), today I came across it again
while searching for a newsgroup that are for organic no-till.

Sorry for the crossposting, but I do believe most of the gardener will
like to read this article.

Regards,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

From: I.B.Bubba )
Subject: ...or wormed their way in?
Newsgroups: talk.politics.mideast, soc.culture.israel,
soc.culture.palestine
Date: 1999/01/13

Earthworms have long been associated with healthy, productive soils.
In his 1881 book entitled. "The Formation of Vegetable Mould through
the Action of Worms," the great biologist Charles Darwin stated that,
"It may be doubted whether there are many other animals which have
played so important a part in the history of the world, as have these
lowly, organized creatures."
Although earthworms are known to be beneficial to soils, their degree
of importance in different agricultural systems is poorly understood.
This publication provides basic information on earthworm ecology, the
effects of earthworms on soil properties and processes, and the
influence of soil management practices on earthworms. It concludes
with a section on how to encourage the buildup of earthworm
populations in agricultural fields, as well as some remaining
questions that require further study.

General Ecology

There are thousands of species of earthworms in the world. Those that
live in the soil can generally be grouped into three major behavioral
classes: the litter-dwellers, shallow soil dwellers, and
deep-burrowers. The litter-dwelling species live in the litter layer
of a forest, for example, and are generally absent from agricultural
fields. Typical agricultural fields may
have one to five different shallow-dwelling species and perhaps one
deep-burrowing species.

The deep-burrowers ("nightcrawlers") build large, vertical, permanent
burrows that may extend 5 to 6 feet deep or more. They pull plant
residues down into the mouth of their burrow, where the residues
soften and can be eaten at a later time. Nightcrawlers construct
middens over the mouth of their burrows. Middens are a mixture of
plant residues and castings (worm feces) and probably serve as
protection as well as a food reserve. Because nightcrawlers require
residues at the surface to pull down into their burrows, we do not
expect to find any nightcrawlers in fields which routinely leave no
surface residue cover (i.e. moldboard-plowed). The species of
nightcrawler in the north-central region is Lumbricus terrestris. The
length of adult nightcrawlers is usually 4 to 8 inches or more.

The shallow-dwelling worms (known as redworms, grayworms, fishworms,
and many other names) are comprised of many species that live
primarily in the top 12 inches of soil. Adult length is usually 3 to 5
inches. They do not build permanent burrows, but instead they randomly
burrow throughout the topsoil, ingesting residues and mineral soil as
they go. Because they do not
require residues at the surface specifically, we do not expect them to
be as sensitive to residue management as are the nightcrawlers.
However, they are affected by the amount of surface mulch because of
the impact on soil temperature and moisture extremes. This is
discussed in more detail in the section on tillage.

Earthworms are seasonal in their activity. The shallow-dwellers are
active in spring and fall but generally enter a resting state in
summer and winter. As the soil starts to heat up and dry out in late
spring (typically May in the North Central states), the
shallow-dwellers move a little deeper (perhaps 18 inches), curl up in
a ball, and secrete a mucus to try to keep from drying out. They spend
most of the summer in that state. In fall, when the soil starts to
cool and become wetter, they become active again, but then often enter
into a hibernation state for the winter. The nightcrawlers also tend
to be more active in spring and fall, but they may not go into a compl
ete resting state in summer or winter since they can retreat to the
bottom of their burrows during extremes of heat or cold. The best time
to observe or count earthworm populations is early- to mid-spring
(often April in North Central states), or late fall (November).

Earthworms have both male and female sexual organs. Most species
require a partner for mating. During mating, sperm are exchanged and
stored in one of the segments of the worm. The cocoon casing is then
produced by the clitellum (the band seen on mature worms), and the
worm "backs out" of the casing, depositing the sperm and eggs into the
casing as it passes over the appropriate segments. The cocoon (2-4 mm
in diameter) then incubates in the soil for several
months, depending on soil conditions, before one young worm (or two
for some species) emerges. New worms will generally only emerge when
soil moisture and temperature conditions are suitable.

Effects on Soil Properties

The degree of importance of earthworms in maintaining soil and crop
productivity will vary depending on circumstances. Earthworms are
almost always beneficial, when present, but they may not be necessary.
Some soils can be very productive without the presence of earthworms.
The worms have sometimes been shown to improve crop growth and yield
directly, but more often their activity affects crop growth indirectly
through their effects on soil tilth and drainage.

Earthworms can have significant impacts on soil properties and
processes through their feeding, casting, and burrowing activity. The
worms create channels in the soil, which can aid water and air flow as
well as root development. The shallow-dwelling worms create numerous
small channels
throughout the topsoil, which increases overall porosity and can help
improve water and air relationships. Nightcrawlers create large
vertical channels, which can greatly increase water infiltration under
very intense rainfall or ponded conditions. Nightcrawler channels can
also aid root proliferation in the subsoil, due both to the ease of
root growth in a pre-formed channel and the higher nutrient
availability in the cast material that lines portions of the burrow.
Earthworm casts, in general, are higher in available nutrients than
the surrounding mineral soil, because the organic materials have been
partially decomposed during passage through the earthworm gut,
converting the organic nutrients to more available forms.

Earthworms improve soil structure and tilth. Their casts are an
intimate mixture of organic material and mineral soil and are quite
stable after initial drying. The burrowing action of the worms moves
soil particles closer together near burrow walls, and the mucus
secreted by the worms as they burrow can also help bind the soil
particles together. Increased porosity, plus mixing of residues and
soil, are additional ways that earthworms improve soil structure.

The mixing of organic materials and nutrients in the soil by
earthworms may be an important benefit of earthworms in reduced
tillage systems, especially no-till. The earthworms may, in effect,
partially replace the work of tillage implements in mixing materials
and making them available for subsequent crops. In natural ecosystems
such as forests, organisms recycle last years leaf litter into the
soil for release of nutrients. With no-till planting we may also
depend more on earthworms and other soil organisms to do this mixing
for us. It seems appropriate, therefore, to try to determine how we
can manage soils to encourage the organisms and their activity.

Management Impacts on Earthworms

When we manage soils for crop production, we are also managing the
habitat in which earthworms and other organisms live. Management
practices affect earthworm populations by affecting food supply
(location, quality, quantity), mulch protection (affects soil water
and temperature), and chemical environment (fertilizers and
pesticides). By considering how these factors are changed in different
management systems, we can often predict the general effects on
earthworm
populations for systems that have not been studied.

Productive pasture fields will usually have much higher earthworm
populations than row-cropped fields, primarily because of the large
amounts of organic materials that are continually being added to the
soil. Continuous root growth and subsequent death and decay, plus
animal manure,
provide a large food supply that can maintain high earthworm
populations. In addition, the pasture plants act as a mulch to buffer
the soil against rapid changes in temperature. Pasture fields are also
not usually tilled, and thus burrow systems are left undisturbed.

Within row-cropping systems, using tillage systems which leave surface
residue, is one of the most important ways that earthworm populations
can be influenced. No-till systems usually have higher earthworm
populations than do conventional moldboard plow systems, due to
increased food supply and mulch protection. With residues on the soil
surface, the food supply is available to the earthworms for a longer
time than if residues are incorporated with a tillage implement. In
addition, the surface residues act as a mulch and slow the rate of
soil drying in late spring and freezing in late fall. This can
lengthen the active periods for the worms, allowing them
to feed and reproduce a little longer in both spring and fall. Surface
residue also gives the earthworms more time to acclimate to the summer
or winter and move down into their resting state. No-till is even more
important for nightcrawlers than for the shallow-dwelling worms.
Because nightcrawlers feed primarily on residues at the surface,
pulling them into their permanent burrows, a clean-till system is not
very conducive to nightcrawlers. The surface food supply is not
present in plowed soils, and the top portion of the permanent burrow
must be reformed after any tillage operation. Although a few
nightcrawlers may be present in plowed fields, often they will not be
present at all.

Tillage systems that are intermediate between the extremes of
moldboard plowing and no-till will tend to have intermediate
populations. The amount of surface residue cover is the key factor to
consider when assessing different possible tillage practices for a
field, as well as establishing conditions which encourage earthworm
populations.

Data collected in Indiana and Illinois over 10 years confirms the
generalizations just discussed. Earthworm populations were counted
after 10 years of tillage plot history on a dark, poorly-drained silty
clay loam soil near West Lafayette (Table 1). Very few worms were
found in the continuous corn plots under either plow or no-till, and
there were no statistically
significant differences between the two treatments. Populations were
surprisingly low and may have been affected by drought conditions the
summer before the survey.

If you'd like to dig into this a little deeper:
http://hermes.ecn.purdue.edu:8001/ht.../agr/acspub/ht
ml/AY/ay279.html

Roger Alexander wrote:
snipped to prevent a double dose of boredom for you

"nswong" wrote in :

Hi All,

This is the best article about earthworm I read before on a
website(forgotted where I read already), today I came across it again
while searching for a newsgroup that are for organic no-till.

This previously quoted article is almost if not identical to the longer
article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

"Salty Thumb" wrote in message
...

This previously quoted article is almost if not identical to the
longer
article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

I think do read this article one or two year ago, since the
poster(I.B.Bubba) said it's a strip down version, I think it's better
to use his version than on the website.

BTW: Salty, I do saw your other posting, but it will take me quite a
lot of time to reply you due to my bad English. It's 1:05 AM here now,
I may reply you by tonight.

Regards,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

"nswong" wrote in :

"Salty Thumb" wrote in message
...

This previously quoted article is almost if not identical to the
longer article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

I think do read this article one or two year ago, since the
poster(I.B.Bubba) said it's a strip down version, I think it's better
to use his version than on the website.

BTW: Salty, I do saw your other posting, but it will take me quite a
lot of time to reply you due to my bad English. It's 1:05 AM here now,
I may reply you by tonight.

no problem, take your time.

"Salty Thumb" wrote in message
news
This previously quoted article is almost if not identical to the
longer article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

I just realize this is one of the link you give me before, since I do
save it offline in my Todo foulder few days ago, but not read at it
yet.

I think it's good for me to review this article again, may understand
more from this review then the previous reading.

no problem, take your time.

Today I'm dumping rice hull to my land again, will be busy in these
few days. :-)

Thanks for the link,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

"nswong" wrote in message
...
"Salty Thumb" wrote in message
news
This previously quoted article is almost if not identical to the
longer article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

I just realize this is one of the link you give me before, since I do
save it offline in my Todo foulder few days ago, but not read at it
yet.

I think it's good for me to review this article again, may understand
more from this review then the previous reading.

no problem, take your time.

Today I'm dumping rice hull to my land again, will be busy in these
few days. :-)

Thanks for the link,
Wong

Ni Hau Wong:

Where do you live?

John

"John Watson" wrote in
news:s3pJc.81442$a24.52822@attbi_s03:


"nswong" wrote in message
...
"Salty Thumb" wrote in message
news
This previously quoted article is almost if not identical to
the longer article he

http://www.ces.purdue.edu/extmedia/AY/AY-279.html

I just realize this is one of the link you give me before, since
I do save it offline in my Todo foulder few days ago, but not
read at it yet.

I think it's good for me to review this article again, may
understand more from this review then the previous reading.

no problem, take your time.

Today I'm dumping rice hull to my land again, will be busy in
these few days. :-)

Thanks for the link,
Wong

Ni Hau Wong:

Where do you live?

John



Based on his lat and long in his sig., somewhere in Indonesia I
think.

"John Watson" wrote in message
news:s3pJc.81442$a24.52822@attbi_s03...

Ni Hau Wong:

Ni Hau. :-)

Where do you live?

Now at my hometown, a town called Kota Bharu in a country called
Malaysia.

Cheers,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

"nswong" wrote in message
...
"John Watson" wrote in message
news:s3pJc.81442$a24.52822@attbi_s03...

Ni Hau Wong:

Ni Hau. :-)

Where do you live?

Now at my hometown, a town called Kota Bharu in a country called
Malaysia.

Very tropical, great place for Hoya and Orchid collections.

Mary


Cheers,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

"Mary" wrote in message
news:yeIJc.101314$XM6.100533@attbi_s53...

Very tropical, great place for Hoya and Orchid collections.

Yah, I do saw wild orchid while I work in a jungle at age 16.

Regards,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m

In article , nswong wrote:

Yah, I do saw wild orchid while I work in a jungle at age 16.

I saw a wild orchid a few weeks ago while soaking in a California
hot spring. What's your point?

--
http://www.spinics.net/photo/

wrote in message
...

Yah, I do saw wild orchid while I work in a jungle at age 16.

I saw a wild orchid a few weeks ago while soaking in a California
hot spring. What's your point?

1. The only place I do saw wild orchid are in jungle, not something
that you will found at road side.
2. Nowaday, I will not see wild orchid even in a jungle. May be still
can find in those really big jungle.

I believe pollution here will make me die earlier.

Regards,
Wong

--
Latitude: 06.10N Longitude: 102.17E Altitude: 5m