Cirad / Exposition itinérante COTON
Traduction anglaise v1-02/2007
Cotton, a bush that grows on every continent
Cotton belongs to the family Malvaceae.
Of the 50 cotton species, two produce the bulk of the world’s cotton:
Gossypium hirsutum (90% of world output), Gossypium barbadense (5% of world output).
Cotton is found on all five continents, in a strip between the latitude of Sin Kiang in the northern
hemisphere and the South African plains in the southern hemisphere.
It is a perennial that is grown as an annual, ie sown again every year. It needs heat, a lot of
sunshine, and water, particularly during flowering.
On any given plant, there may be buds, flowers and fruits, or “bolls”
Cotton flowers as it grows. This is known as continuous growth. On any given plant, there may
be buds, flowers and fruits, or “bolls”, at the same time.
Cotton flowers are yellow on opening and turn purplish pink once pollinated. They then wilt and
become bolls.
Once ripe, the bolls split to reveal the cotton
Once they are ripe, the bolls split open, revealing a small white ball of cotton.
Each boll contains around thirty seeds, split between four or five loculi. It is the seeds that
produce cotton fibre.
Cotton is naturally either white or coloured. There are varieties that produce brown, khaki,
yellow and greyish-green fibre.
In industrialized countries, the development of chemical dyes has boosted demand for white
fibres.
Cotton picking: by hand or machine
In many African countries, seed cotton is hand-picked, which is highly labour-intensive. In the
United States, Australia, Europe, Brazil and Uzbekistan, it is picked using huge machines:
“cotton pickers” and “cotton strippers”.
In industrialized producing countries, once 80% of the bolls have split, the farmer sprays his field
with a product known as ripener, which—as its name suggests—speeds up ripening. He then
sprays it with a defoliant that makes the leaves fall off so as to facilitate machine-picking. Once
95% of the bolls have split, the crop is ready for picking.
This is where the cotton pickers come in. These machines can pick 800 kilos of seed cotton an
hour, compared to between 50 and 80 kilos a day for human pickers.
The product of the harvest is called seed cotton
Each seed is surrounded by long, very fine fibres: cotton fibres. This is why the crop is referred to
as seed cotton.
The amount of trash in the seed cotton depends on the picking method. Hand-picked cotton is
cleaner than machine-picked, and thus requires fewer cleaning operations, hence it retains its
intrinsic properties.
A tonne of hand-picked cotton gives an average of 400 kilos of fibre, 500 to 550 kilos of
cottonseed and 50 to 100 kilos of trash.
Ginning separates the fibre from the seeds
The seed cotton is transported to the ginning plant, where it is machine-cleaned to remove any
large impurities (leaves, stems, bolls, etc). It is then ginned, ie the fibre is separated from the
seeds.
The fibre is then cleaned by machines that remove any smaller impurities. By the end of the line,
the cotton fibre is clean.
The prepared fibre is then compressed into 225-kilo bales. Modern plants produce a bale a
minute, or more than 1000 bales a day, which are then sent to textile factories.
From fibre to yarn, to fabric
Clumps of cotton fibre are delivered to textile factories in bales of different origins. They are then
prepared:
- carding: the fibres are untangled and separated, before being bunched together in long slivers.
- drawing out: the fibres in each sliver are combed and several slivers are combined to make a
more regular rope.
- spinning: the fibres are twisted to make yarn.
- weaving or knitting: weaving produces stronger fabrics, while knitting makes stretchier, softer,
breathable fabrics.
Cottonseed provides oil and presscake
The seed kernel is very rich in oil and protein, but contains a toxic pigment: gossypol. Pressing
the kernels produces an excellent, gossypol-free edible oil.
Cottonseed oil is the sixth most widely consumed oil worldwide. It is high quality, rich in
polyunsaturated fatty acids, and cholesterol-free.
The protein-rich paste left after oil extraction is made into presscake that is fed to ruminants
(cows and sheep), the only animals that can detoxify gossypol during digestion. Cottonseed is the
world’s second-largest source of vegetable protein.
It’s the twisting that makes the yarn
There are between 100 and 250 cotton fibres from 1 to 3 centimetres long in the thickness of a
cotton thread.
The fact of twisting the fibres gives the yarn its cohesion and strength. It takes just 20 grams of
fibre to make 1 kilometre of fine yarn.
Fibre quality can be measured: strength, stretchability, evenness and defects.
Fabric fragments dating back 8000 years
The earliest cotton fabric fragments discovered so far date back 8000 years!
They were found in the Indus Valley (now Pakistan). The oldest cotton fabric fragments found in
Mexico are estimated to be 7200 years old! The art of making cotton fabrics spread from India to
Europe and the Mediterranean, through Alexander the Great and the Arab conquests.
The words cotton in English and coton in French come from the Arabic word el kutn. Direct trade
between Europe and India really took off with the opening of the route to India by Vasco da
Gama in 1497.
It was the invention of the saw gin that heralded the boom in cotton growing in the United States,
and with the invention of the jacquard loom, cotton contributed to the Industrial Revolution in
Europe, as spinning and weaving quality improved in leaps and bounds.
Fibre classification, a delicate art
Before delivery to the customer, cotton bales are grouped together in batches of uniform quality.
To this end, fibre quality has to be assessed; this is known as fibre classification, which is done
by hand, with the naked eye and using measuring devices.
- Samples are taken from every cotton bale to estimate fibre length and also colour (yellow,
cream or white), sheen and trash content.
This is done by comparison with standard cottons.
- The CIRAD cotton technology laboratory is one of a network of six international reference
laboratories that establish standard values for instrumental classification of cotton fibre.
Promoting African cotton quality
African cotton is very high quality. To promote its merits, satisfy demand from spinners and
reaffirm its quality approach, the Dagris Group is implementing a branding policy, in which the
purity index is a determining factor.
- The brand names L8 and F8 have been registered, reflecting the increase in quality in line with
the index.
- A fair trade cotton project has been initiated by Dagris and its partners Max Havelaar France,
the French Foreign Ministry and the Centre de Développement des Entreprises (CDE).
It should enable producer groups that satisfy certain social and ecological standards and quality
criteria to promote their products more effectively.
Cotton has to cope with many enemies
Cotton is affected by viral, bacterial and fungal diseases, and is also one of the crops most subject
to insect attacks.
Insects cause considerable damage. They result in yield losses and fibre deterioration. For a long
time, chemicals were the only solution to the problems posed by insects (some of which have
now become resistant!).
In some countries, crops are sprayed with insecticides up to 20 times a year. In others, farmers
are turning to “integrated” pest management, which combines several techniques in order to cut
pesticide use.
Creating new cotton varieties to improve production and fibre quality
Researchers use different methods for this:
• “genealogical”, or conventional, breeding. Each year, 2.5 million hectares (7% of the area under
cotton worldwide) are planted with varieties created by CIRAD and its partners using these
conventional methods.
• participatory breeding: farmers choose what they see as the most worthwhile plants, and work
with researchers to choose the strains to be propagated.
Each year the farmers are responsible for sowing their varieties.
• DNA marker-assisted breeding, which enables direct selection of worthwhile genes within the
plant genome.
This cotton breeding programme under way at CIRAD set out to improve the intrinsic quality of
G. hirsutum fibre.
• cotton genetic modification, which makes it possible to introduce new agronomically
worthwhile genes (insect- or drought-resistance) and explain how the plant genome functions.
CIRAD is currently assessing the impact of such varieties on smallholder production systems in
developing countries.
Cotton-based biodegradable materials
CIRAD is working on the particular properties of the protein extracted from cottonseed kernels.
This protein could be used to make biodegradable materials for agricultural use, to replace certain
plastics derived from petrochemicals.
It should be possible to produce flexible or rigid films for use as wrappings and mulches,
composite materials and seed coatings.
Making biofuels from cotton
Like rapeseed and sunflower in Europe, cotton is a potential biofuel source.
Several co-products could be used:
• cottonseed oil, in crude or esterified form (diesters). The oil and oil esters could be used in
compression ignition (diesel) engines;
• stem and seed hull waste, to make oil by pyrolysis, or waste fibre from ginning plants, to make
ethanol by fermentation;
• cottonseed “alcohol” could be used in spark ignition (petrol) engines.
Dagris is launching a programme to promote oil crops to supplement cottonseed oil production
and produce biofuels by esterification. This would provide extra income for farmers in the
African cotton-growing zones.
The global price for cotton fibre has slumped
World prices have been falling since the 1980s.
The trend has been exacerbated by the fact that some countries pay subsidies to their farmers,
boosting production volumes.
Prices now fall short of production costs in most producing countries.
Even in those countries with the lowest production costs, for instance in the “franc zone” of
Africa, the production chain is fighting for survival.
A matter of life or death for some countries
The protest lodged by four African countries against the subsidy policies in place in several
countries has highlighted the economic and social importance of cotton in Africa.
In the countries of the “franc zone”, cotton provides 10 million people with a living and is a
major source of currency and of jobs in rural areas.
Some countries have managed to implement support measures to compensate for the drop in
revenue from cotton. However, those measures will not be enough to provide a long-term
solution to the current crisis.
Quel avenir pour la planète coton ? / What is the future for the cotton world?
Zones colorées = zones de production / Coloured zones = producing zones
Production mondiale de fibre de coton en 2004-2005 / Global cotton fibre production in 20042005
Marché 2004-2005 en milliers de tonnes / 2004-2005 market in thousand tonnes
USA / USA
Chine / China
Corée / Korea
Japon / Japan
Mexique / Mexico
Inde / India
Pakistan / Pakistan
Brésil / Brazil
Turquie / Turkey
Ouzbékistan / Uzbekistan
Grèce / Greece
Argentine / Argentina
EU-15 / EU-15
Syrie / Syria
Kazakhstan / Kazakhstan
Turkménistan / Turkmenistan
Thaïlande / Thailand
Australie / Australia
Paraguay / Paraguay
Espagne / Spain
Egypte / Egypt
Tajikistan / Tajikistan
Bengladesh / Bangladesh
Indonésie / Indonesia
Taïwan / Taiwan
Amérique du Sud / South America
Asie / Asia
Europe / Asia
Afrique francophone / French-speaking Africa
Reste du monde / Rest of world
Production / Production
Exportation / Exports
Importation / Imports
D’après « World Cotton Map » / Based on “World Cotton Map”