پرورش نوغان (کرم ابریشم) و استحصال ابریشم ...

Phyto

مدیر تالار مهندسی كشاورزی
step 1: raising silkworms and harvesting cocoons


silkworms are really not worms at all. silk worms are the larvae of ‘bombyx mori’ moths and silkworms are actually
domesticated insects. native to china, the silkworm does not longer exist in the wild, after so many centuries of
inbreeding the silkworm is incapable of flight, mates quickly after emerging from its crysalis, and dies a day or so after
laying its eggs. designboom illustrates the several stages of sericulture, which begins with hatching silkworm eggs ...



image © designboom

an ounce of silkworm eggs yields about 35,000 worms, during gestation, which lasts approximately three weeks, the eggs
must stay between 25 and 31 °C, in a tray with high humidity. as they hatch, each of the tiny creatures must be carefully
moved to a ‘petri dish’, a circular flat bamboo tray, to be fed with fresh mulberry leaves several times a day.
when the baby silkworms emerge from their eggs, they are really tiny, about the size of a lowercase ‘i’, and almost black.
from the moment they emerge they start eating with an enthusiasm that never abates.
when designboom entered the farmer’s household we could hear them constantly chewing.
the worms are protected from harmful flying insects by wrapping the trays in homespun cotton
 

Phyto

مدیر تالار مهندسی كشاورزی


the newly born silkworm only eats mulberry leaves. a silk farmer must have a ready supply of mulberry leaves and fruits
close at hand, even one missed feeding can kill the sericulture. there are times of the year when the mulberry leaves are not
around... continued food shortages can decrease the quality of silk any survivors make.
if there are shortages anyway, lettuce makes a decent emergency dish, as long as it is well-washed (pesticides kill)
and dried thoroughly.
 

Phyto

مدیر تالار مهندسی كشاورزی


despite revolutionary changes in methods of manufacture, the ultimate basis of silk remains the tiny, inconspicuous-looking
silkworm and the most critical period in silk production comes during the silkworm’s brief life span of around 20/24 days.
nearly all silkworm-producing moths belong to the family ‘bombycidae’, of which one member, ‘bombyx mori’ is responsible for
most of the world’s silk.

 

Phyto

مدیر تالار مهندسی كشاورزی
at the beginning every few days, the worms need to be moved to a clean tray with fresh food.
members of the farmer’s household must spend a growing amount of time to their bamboo trays, also because
silkworms produce quite a lot of excrement and cleaning the trays is not a job for the weak-stomached.
they continue feeding and moving the silkworms, dividing the colonies when the silkworms are too large or hungry for
the numbers in that tray. by the fourth week, the largest of the silkworms will be more than 5 cm. long, fat, and hungry
enough that they need to be fed every day



an easy test confirms their readiness to cocooning. the farmer picks them up and looks between their rear pair of legs,
from the underside. if there is a gray mass there, the caterpillar isn't quite ready, but if it's milky and translucent, the silkworm
has pooped its last and is definitely ready. the worms suddenly stop eating and raise their heads - another sign that they are
ready for the all-important job of spinning cocoons
 

Phyto

مدیر تالار مهندسی كشاورزی


at that stage they are removed from their feeding trays



the ‘bombyx mori’ worms are now inserted in a specially woven circular bamboo scaffolding, which will make the cocoons
more uniform in shape and easier to collect
 

Phyto

مدیر تالار مهندسی كشاورزی


again, worms are protected from harmful flying insects by wrapping the trays with fine nets.
there seems to be always a few dead silkworms in each tray. while a dramatic increase in the mortality rate is reason for
concern, silkworms are insects, and farmers can expect that less than half of the silkworms will reach full maturity



each silkworm now doubles itself up on its back, and by contracting secretes, from an opening under its mouth, a steady
stream of liquid silk, coated with sericin, which hardens on exposure to air. they're starting to lay out the support strands for
their cocoons, although they may not yet be serious about cocooning



some of the larger caterpillars are climbing the walls of the tray (they've done this before, to shed their skins, but this time
their heads are pointing toward the lid) and the busy silkworms are guided by figure of eight movements of their heads, to
dispose the liquid silk in layers, forming the cocoon
 

Phyto

مدیر تالار مهندسی كشاورزی


after some 36 hours, the worms are sealed within a yellow cocoon, embarked on the process of metamorphosing into a moth

 

Phyto

مدیر تالار مهندسی كشاورزی


the worms have spun thousands of gossamer little cocoons



the satisfactory cocoons are now in a clean tray. see the lustrous, golden color.
care must be taken not to damage them when removing from the old trays.
the entire process, from silkworm egg to complete cocoon, takes about twenty-five days.
silk worms transform themselves, inside the cocoon, into a chrysalis and then into a butterfly... most of the cocoons are used for the next step in silk making but some of them leave the cocoon as a butterfly.
it usually secretes a liquid onto the silk threads to dissolve them, so it can emerge.
the new moths must be moved to another tray so the mess they make while mating and laying eggs doesn't get all over
the hard-earned silkcocoons. the males (small) will die once the deed is done, while the females will stick around to
lay about 200 - 300 eggs each
 

Phyto

مدیر تالار مهندسی كشاورزی
step 2: thread extraction


the story of silk began more than four thousand years ago in the court of china’s first emperor.
it is said that a young concubine named lei tsu, by way of experiment, has discovered the ‘finest natural textile thread known to man’.
the art of waving silk, first restricted to members of the imperial court spread to lower levels of chinese society
and achieved widespread fame. gradually a trade route to the west emerged. a tortuous passage known as ‘silk road’
wandered through hostile lands and ended thousands of miles away at market places in the middle east.
for centuries only the chinese knew the secrets of silk production and the exportation of silkworms was strictly forbidden.
around 140 BC silkworm eggs and and mulberry cuttings reached khotan, in present-day afghanistan,
allegedly smuggled by a chinese princess who went to marry the king and found the prospect of a silkless life unbearable.
from then it went to india and a century later to korea and japan; around the same time the art was moving south with
chinese minority groups into present-day indo-china and thailand.
since then silk weaving is an integral part of north east thailand’s countless villages
 

Phyto

مدیر تالار مهندسی كشاورزی


the fresh and fragile cocoons are ready to be scooped into the reeling pot. each cocoon consists of many yards of tightly woven silk thread
 

Phyto

مدیر تالار مهندسی كشاورزی


most steps of traditional silk making in thailand’s villages in the north-east are done by women and take place in open areas.
in the reeling process, a special wooden device is used to locate the end of the filament, after which it must be carefully
unwound, a process that not only requires hard work over a boiling pot, but also practiced skill to keep the threads unbroken.
the village woman immerses the cocoons in boiling water to help soften the thick gum coating



in the cultivation of silkworms, to not damage the continuity of the thread, the cocoons are placed in boiling water to kill the chrysalis
 

Phyto

مدیر تالار مهندسی كشاورزی


it begins to unwind, forming an extraordinarily long thread of great strength yet as delicate as a spider’s web



a spatula removes the outside layers of the cocoon, then, having found the end of the single cocoons
 

Phyto

مدیر تالار مهندسی كشاورزی


after this process, the remaining, cooked silkworm will be eaten by the village youngsters. it contains a lot of protein
البته این قسمتش فکر نکنم به مذاق ما زیاد خوشایند باشه!!
 

Phyto

مدیر تالار مهندسی كشاورزی
step 3: dyeing



after washing and degumming, there is a bleaching (and drying) process before dyeing
 

Phyto

مدیر تالار مهندسی كشاورزی


most of the dyes are obtained from natural resources of the immediate sourrounding, offering an exquisite palette of different
hues. these leaves of the wild indigo plant are a major source of natural black or blue, other colors are obtained from:
yellow - jackfruit
orange - bisea
red - sappanwood
maroon, pink and purple red - lac
green - myrobalan
grey - coconut
blue-grey - eucalyptus
green-grey - butterfly pea
purple grey - simarubaceae
brown - cutch
khaki - mango and cutch



dried indigo. all stages of the process are performed by the women of the village, from plant harvesting, through dye vat care,
to the dyeing step itself
 

Phyto

مدیر تالار مهندسی كشاورزی


the blue dye derived from crushing and composting the indigo plant. the natural fermentation process reduces the indigo in a
vat changing the colour from yellow to green to blue after exposure to air. the only ingredients required are the indigo cake,
soda ash, wheat bran and madder (an enzyme that creates the fermentation and deoxidizes the indigo).
 

Phyto

مدیر تالار مهندسی كشاورزی


the colour derived from soaking fabric in hot mixture of indigo leaves.
the bundles of threads are soaked in the dye pots for several times over many days to achieve the proper color tone and
quality. then the colours need to be fixed (roots of natural morinda germinata are reported to serve as a fixing agent).
these traditional methods of dye production have elsewhere al most been driven to commercial extinction,
and dyeing with synthetic indigo and a wide variety of other synthetic colors is booming.
in this study (conducted by professor wichai lailawitmongkhol - see intro page) the indigenous practices are documented
and taught to the village people before they are completely lost
 

Phyto

مدیر تالار مهندسی كشاورزی


after the process the threads are hanging out to dry



beautiful color variations of the yarn, ready for spinning onto bobbins
 

Phyto

مدیر تالار مهندسی كشاورزی
step 4: spinning


even today, despite the introduction of a wide range of new techniques, the traditional spinning wheelis still
necessary for a variety of purposes. spinning wheels are used for unwinding dyed silk skeins onto bobbins
for the warping process



bamboo spools
 

Phyto

مدیر تالار مهندسی كشاورزی


preparing the thread involves multiple steps



the woman is winding the spool by the means of a hand crank



another threading step
 

Phyto

مدیر تالار مهندسی كشاورزی


the silk thread moves from the bobbins through a worker’s hands onto a spinning device



the spinning device is powered by bycicle pedals and finishes the thread



by passing through the hands the silk thread acquires a lustrious sheen
 

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