Cotton

Cotton is a soft fiber that grows around the seeds of the cotton plant (Gossypium spp.), a shrub native to the tropical and subtropical regions of both the Old World and the New World. The fiber is most often spun into thread and used to make a soft, breathable textile, which is the most widely used natural-fiber cloth in clothing today. The English name descends from the Arabic word al qutun, (whence also the Spanish word algodón) meaning cotton fiber.

Cotton fiber (once processed to remove seeds and traces of wax, protein, etc.) consists of nearly pure cellulose, a natural polymer. Cotton production is very efficient, in the sense that, ten percent or less of the weight is lost in subsequent processing to convert the raw cotton bolls into pure fiber. The cellulose is arranged in a way that gives cotton fibers a high degree of strength, durability, and absorbency. Each fibre is made up of twenty to thirty layers of cellulose coiled in a neat series of natural springs. When the cotton boll (seed case) is opened the fibres dry into flat, twisted, ribbon-like shapes and become kinked together and interlocked. This interlocked form is ideal for spinning into a fine yarn.

Picking cotton in Georgia, United States

Cotton plant

Cotton fiber originates from the cotton plant, an important crop in tropical climates and warm temperate climates. Commercial species of cotton plant are Gossypium hirsutum (U.S.A. and Australia), G. arboreum, G. herbaceum (Asia), and G. barbadense (Egypt).

History

Cotton has been used to make very fine lightweight cloth in areas with tropical climates for millennia. Some authorities claim that it was likely that the Egyptians had cotton as early as 12,000 BC, and evidence has been found of cotton in Mexican caves (cotton cloth and fragments of bloody fibre interwoven with feathers and fur) which dated back to approximately 7,000 years ago. There is clear archaeological evidence that people in South America and India domesticated different species of cotton independently thousands of years ago.

The earliest reference to cotton is in India. Cotton has been grown in India/Pakistan for more than 6,000 years since the pre-Harappan period, and it is later referred to in the Rig-Veda, composed in 1500 BC. A thousand years later, the famous Greek historian Herodotus wrote about Indian cotton: "There are trees which grow wild there, the fruit of which is a wool exceeding in beauty and goodness that of sheep. The Indians make their clothes of this tree wool". (Book iii. 106)

In Peru, cotton was the backbone of the development of coastal cultures such as the Moche and Nazca. Cotton was grown upriver, made into nets and traded with fishing villages along the coast for large supplies of fish. The Spanish who came to Mexico in the early 1500s found the peoples there wearing cotton clothing and growing it.

During the late mediaeval period, cotton became known as an imported fibre in northern Europe, without any knowledge of what it came from other than that it was a plant; people in the region, familiar only with animal fibres (wool from sheep), could only imagine that cotton must be produced by plant-borne sheep. John Mandeville, writing in 1350, stated as fact the now-preposterous belief: "There grew there India a wonderful tree which bore tiny lambs on the endes of its branches. These branches were so pliable that they bent down to allow the lambs to feed when they are hungrie.". This aspect is retained in the name for cotton in many European languages, such as German Baumwolle, which translates as "tree wool".

By the end of the 16th century AD, cotton was cultivated throughout the warmer regions in Africa, Eurasia and the Americas.

The Indian cotton processing industry was eclipsed during the British Industrial Revolution, when the invention of the spinning jenny (1764) and Arkwright's spinning frame (1769) enabled cheap mass-production of cotton cloth in the UK. Production capacity was further improved by the invention of the cotton gin by Eli Whitney in 1793. It was in this period that the superiority of the American varieties of cotton was established, owing primarily to the length of the fibers. English traders made the switch from Indian (Asia) cotton to American cotton as the Industrial Revolution got underway. Today, 90% or more of all cotton in cultivation is of the long-staple American varieties.

In the United States, growing the three crops, cotton, indigo and tobacco historically were the leading occupations of slaves. After emancipation, the share cropping system evolved which in many cases differed little from the systems of slavery.

Production and processing

File:Cotton harvest.jpg

Cotton harvesting in Texas.

Today cotton is produced in many parts of the world, including Europe, Asia, Africa, the Americas and Australia. Cotton plants have been selectively bred so that each plant grows more fiber. In 2002, cotton was grown on 330,000 km² of farmland. 47 billion pounds (21 million t) of raw cotton worth 20 billion USD was grown that year.

The cotton industry relies heavily on chemicals such as fertilizers and insecticides, although a very small number of farmers are moving towards an organic model of production and organic cotton products are now available at a very few locations. Historically, in North America, one of the most economically destructive pests in cotton production has been the boll weevil. Due to the US Department of Agriculture's highly successful Boll Weevil Eradication Program (BWEP), this pest has been eliminated from cotton in most of the United States. This program, along with the introduction of genetically engineered cotton containing a gene that codes for a plant-produced protein that is toxic to a number of pests such as tobacco budworm, cotton bollworm and pink bollworm, has allowed a reduction in the use of synthetic insecticides.

Most cotton in the United States, Europe and Australia is harvested mechanically, either by a cotton picker, a machine that removes the cotton from the boll without damaging the cotton plant, or by a cotton stripper which strips the entire boll off the plant. Cotton strippers are generally used in regions where it is too windy to grow picker varieties of cotton and generally used after application of a defoliant or natural defoliation occurring after a freeze. Cotton is a perennial crop in the tropics and without defoliation or freezing, the plant will continue to grow.

The logistics of cotton harvesting and processing have been improved by the development of the cotton module builder, a machine that compresses harvested cotton into a large block, which is then covered with a tarp and temporarily stored at the edge of the field.

Uses

In addition to the textile industry, cotton is used in fishnets, coffee filters, tents and in bookbinding. The first Chinese paper was made of cotton fiber, as is the modern US dollar bill and federal stationery. Fire hoses were once made of cotton.

Denim, a type of durable cloth, is made mostly of cotton, as are most T-shirts.

The cottonseed which remains after the cotton is ginned is used to produce cottonseed oil, which after refining can be consumed by humans like any other vegetable oil. The cottonseed meal that is left is generally fed to livestock.

Fair trade

Cotton is an enormously important commodity throughout the world. However, many farmers in developing countries receive a low price for their produce, or find it difficult to compete with developed countries. This has led to 'fair trade' cotton clothing being available in some countries. The fair trade system was initiated in 2005 with producers from Cameroon, Mali and Senegal.[1]

Old British cotton yarn measures

1 thread = 54 inches (c. 137 cm)
1 skein or rap = 80 threads (120 yards or c. 109 m)
1 hank = 7 skeins (840 yards or c. 768 m)
1 spindle = 18 hanks (15,120 yards or c. 13.826 km)

References and further reading

The Thames and Hudson Manual of Dyes and Fabrics, Joyce Storey, 1978

External links

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