Types of Fibers that are Grown in our Country

1. Cotton:

Cotton (Gossypium Species; Family Malvaceae) constitutes more than 70 per cent of the total world consumption of the fibres.

It is one of the oldest fibre plants. It was known to the ancient world long before the written records were made. It has been under cultivation since ancient times in two widely separated continents, South Asia and Central America.

In India, the major cotton- growing states in order of importance are Maharashtra, Gujarat, Karnataka, Madhya Pradesh, Punjab, Andhra Pradesh, Tamil Nadu, Rajasthan and Haryana.

These states together contribute 95 per cent of India’s cotton acreage. Gujarat leads in cotton production, followed by Punjab, Maharashtra, Karnataka, Haryana, Andhra Pradesh, Tamil Nadu, Rajasthan and Madhya Pradesh. India is not only self-sufficient but exports substantial quantity of cotton to other countries.

The predominant species cultivated in India is G. hirsutum which accounts for about 50 percent in area, followed by G. arboreum with 29 per cent and G. herbaceum with 2.10 per cent. The area under G. bardadense is negligible.

Morphology:

The plants are perennials, but cultivated as annuals. They range from herbaceous plants 2-6 feet high to small woody trees 15-30 feet high. The flowers arise singly from the terminal buds of sympodia, they are pedunculate, the length of the peduncle varying with cultivar. Flowers are large and showy.

They are surrounded by an involucre of large, leafy bracts (epicalyx) that are generally persistent in many cultivars. Numerous stamens with a kidney-shaped, one-celled (monothecous) anther are united by their filaments into a staminal tube surrounding the style (Fig. 12.3).

The cotton fruit (boll) is a spherical or ovoid leathery capsule (Fig. 12.4) consisting of 3-5 locules or chambers which correspond to the carpel’s number of the ovary. The content of each chamber is called a “lock”, within which 6-9 seeds are present. The cotton seeds are irregularly pyriform in shape and are covered with two types of hairs. Long epidermal hairs of the seed coat, called lint, floss or staple and very short epidermal hairs known as fuzz or lint. Fuzz is usually coloured, while the lint is white and the commercial cotton fibre.

A mature cotton fibre is flattened, twisted tube, being a unicellular outgrowth of the seed coat. It has a thick cellulose wall with numerous pits which facilitate absorption of water and dyes.

Cotton fibres may be broadly classified into three large groups, based on staple length:

1. Long-staple fibres:

The staple length is 1-2.5 inches (i.e., about 2.5 – 6.5 cm), having a fine texture and good lustre. It includes types of high quality fibres such as Sea-Island, Egyptian and American Egyptian (Pima). These are not very commonly grown because of difficulties in their cultivation. This fibre is used in high quality fabric, yarn and hosiery items.

2. The Standard Medium or Intermediate Staple Cottons:

Here the staple length varies from 1.3 to 5.0 cm. The fibre is relatively coarser. It includes American upland cotton. It is quite popular because of high yields.

3. Short-staple fibres:

Indian and other Asiatic cottons belong to this class. The fibres are short, coarse and lustreless. They are mostly used to make coarse and cheap fabrics, carpets and blankets etc.

Cultivated Cottons:

During the long period of cultivation, hundreds of varieties have been developed from wild ancestors through breeding. These varieties differ in their fibre characters as well as in morphological and cultural features.

The cultivated cottons are grouped into the New World Cottons (2 n = 52) and Old World Cottons (2 ft = 26). Most of the important varieties of the former either belong to G. barbadense or G. hirsutum, while most of the Asian and African Cottons (Old World Cottons) belong to G. arboreum and G. herbaceum. In India all these four species are grown. A brief account of these species follows.

1. Gossypium barbadense (2n = 52):

It is native of tropical South America. Its flowers are bright yellow with purple spots. The fruit, or boll, has three valves, and the seeds are fuzzy only at the end. It includes Sea-Island and the Egyptian cotton. It belongs to long staple group with fine, strong and silky fibre. Because of its fine quality it has the greatest demand all over the world. In India it is cultivated in Malabar and South Kanara Coastal regions of Kerala state and some parts of Assam.

(a) Sea-Island Cotton:

It is the finest of all cultivated cottons and is largely grown in West Indies, Fiji and along a narrow strip of coastal mainland and islands of the coast of Florida, Georgia and Southern Carolina. Its fine, strong, light cream-coloured fibres are more regular in the number and uniformity of the twists and have a silkier appearance than those of other cottons. These features are exceedingly valuable a>id Sea-Island cotton is in great demand for making finest textiles, laces, cambric and fine hosiery.

(b) Egyptian Cotton:

It is grown under irrigated conditions not only in the Nile River Valley of Egypt and Sudan, but also to a limited extent in Turkistan, and in New Mexico, Arizona and California in southern U.S.A. The plant is quite similar in appearance to Sea-Island cotton and is probably of hybrid origin. The staple, however, is brown in colour and somewhat shorter in length. Because of its length, strength and firmness this cotton is used for thread, underwear, hosiery, tire fabrics, and fine dress goods. Repeated selection and breeding have resulted in the development of new and better strains, of which Pima is one of the best.

2. Gossypium hirsutum (Upland Cotton; 2n = 52):

It is popularly known as Upland cottons or American cottons and in India as Dharwar Cottons.

This species is a native of Mexico and Central America. Most of the cotton grown in the world today is Upland cotton. Apart from the cotton belt of the southern United States, Upland cotton is grown in Turkistan, South Brazil, Uganda, South and West Africa, Iraq, parts of China. Turkey, Greece, Manchuria, India, Pakistan and Queensland (Australia).

It includes both long and medium stapled cottons. On the basis of staple length, two important varieties of G. hirsutum have been recognized; American upland short staple cotton, and American upland long staple cotton. In India it was introduced in 1840 and now grown in parts of Maharashtra, Madhya Pradesh, Rajasthan, Uttar Pradesh, Tamil Nadu, Andhra Pradesh, Karnataka and Punjab.

The flowers of this species are white or light yellow and unspotted. The bolls are 4-5 valued, and the seeds are fuzzy all over (Fig. 11.1).

3. Gossypium herbaceum (Levant Cotton; 2n = 26):

A native of tropical Africa and the Middle East and is now grown in China, Indonesia, north­western India, Pakistan, Iran, Iraq, Turkistan, Turkey, Greece and in many parts of Africa. The staple is medium to short and more or less coarse but strong. It is utilized for low-quality fabrics, carpels, and blankets and is especially suitable for blending with wool (Fig. 11.2).

4. Gossypium arboreum (Ceylon Cotton, Chinese Cotton or tree cotton; 2n= 26):

This species, the perennial tree, was probably the first to be grown commercially. A native of Indo-China, now cultivated in India, Burma, Malaysia, the East Indies, China, Korea, Japan and Formosa (Taiwan). India and Africa are now the largest producer of this cotton.

The small seeds are covered with greyish green or rust-coloured short hairs (fuzz). Staple, floss or lint (long-hairs) are yellowish white or rusty white, coarse and without luster, but strong and very short. Six races are recognized in this species. In India it is chiefly grown in Bengal, Assam, Madhya Pradesh, Maharashtra, Gujarat and Tamil Nadu.

Cultivation of Cotton:

Cotton is a sub-tropical crop. It thrives well in areas having rainfall varying from 30 inches in Central India to over 100 inches in Assam and Kerala. It can grow in drier areas provided it is irrigated. It requires sufficient rainfall during the early stages of growth, but wants a comparatively dry weather during the flowering and fruiting stage. Rainfall during the boll-opening and harvesting period is definitely harmful.

Cotton needs, on an average, a minimum temperature of 60°Fat germination, 70-80 T for vegetative growth, 80-90°F with cool nights during fruiting period. It cannot withstand frost.

Soil:

Cotton is grown in a variety of soils. It grows equally well in the Indo-Gangetic alluvium, the black cotton soils of Central India, the medium black soils of the Deccan Plateau, and the red and lateritic soils of eastern and southern India. It requires a free-draining soil as it does not tolerate water logging. It is grown mainly as an irrigated crop in the alluvial soils of the north and as a dry crop in the black cotton and medium black soils of Central and Peninsular India. Alkaline soil is not good for cotton cultivation.

The soils well supplied with organic matter and humus are the most productive soils. The lighter soils need liberal application of balanced manure and fertilizers for profitable crop cultivation and on heavy soils the crop does not need only fertilizers but also adequate organic matter to maintain optimum drainage and aeration conditions.

Topping:

It is desirable to remove the apical bud (terminal growing point), a practice called topping, one from each plant at a height of 1 to 1.2 m or between 80-90 days of crop growth. This practice checks growth in length and encourages sympodial branching and profuse boll formation. It also facilitates spraying operations and picking of cotton.

Harvesting:

Cotton is harvested in three or more pickings taken at suitable intervals. The number of pickings varies with the maturity habit of the variety. The season of harvesting varies with the time of sowing and duration of variety. Harvesting begins about six months after sowing and is the most expensive operation of cotton cultivation.

Generally the crop sown in April-June is harvested in October-December, while those sown in June-September and in September-October are harvested from November to March and from March to June, respectively. Harvesting in Northern and Central India is done from October to December, in Gujarat from January to March/April, in Tamil Nadu, Andhra Pradesh and Karnataka from November to June.

In all those areas where labour is cheap cotton is handpicked. Hand picking is continued over a period of two months or more because all the fruits do not ripen at the same time. Cotton is picked as soon as the boll opens. In the western subhumid parts of the world where labour is very scarce, mechanical harvesters are used to pick cotton. In mechanical harvesting, it is necessary to defoliate the plants by spraying chemical such as calcium cyanide. Cotton picked earlier (in the beginning) is of superior quality than the cotton picked at a later stage.

2. Jute:

Jute is most important of the bast fibres, and the second most important plant fibre after cotton. Jute is obtained from the stems of two cultivated species of Chorchorus, namely, C. capsularis (white jute) and C. olitorius (tossa jute) of the family Tiliaceae. It is one of the most important cash crops of North-East India. Though the fibre is somewhat coarse and lignified it can be spun into yarn. This yarn of jute is used for the manufacture of bags and sacks. Exported as manufactured goods or raw fibre, it is a valuable earner of foreign exchange.

The fibre is used for manufacturing packing cloth, hessian and bags for the transport and storage of cotton, wool, foodgrains, pulses etc. Jute is also used for making rugs, carpets, curtains, upholstery, linings, ropes and twines. Green leaves of C. olitorius are edible. Stalks stripped of fibre are used as fuel and for making gunpowder charcoal. Short fibres and pieces from the lower ends of the stalks constitute jute butts, which are used to some extent in paper making. India not only grows most of the jute, but it is the largest manufacturer and exporter of jute products.

History and Origin:

The plant is mentioned as a food in the Bible as well as in ancient Egyptian and other early Mediterranean literature, but its use as a textile fibre is somewhat obscure. According to Kundu (1959), the primary centre of origin of C. olitorius is Africa with a secondary centre in India or Indo-Burma. C. capsularis is, however, not found in Africa and Australia; its centre of origin is believed to be Indo-Burma.

Production:

Before partition of this country in 1947, India had monopoly in the production of jute. Areas producing high quality jute (districts of Mymensingh, Dacca and Tippera) went to East Pakistan (now Bangladesh). However, with concerted efforts India has once again attained first place in jute production. Now 80 per cent of the total world’s jute production comes from India and Bangladesh. Other countries are China, Burma, Nepal and Brazil. Some jute cultivation is done in Taiwan and Thailand also.

Bangladesh is by far the largest exporter of raw jute, whilst India leads in the export of manufactured products. In India, the major jute growing states are West Bengal, Assam, Bihar, and Orissa. Some cultivation is done in Uttar Pradesh, Tripura and Meghalaya also.

Morphology:

The fibre cultivars of both species are herbs up to 5m tall with straight, cylindrical stems branching only at their tops when sown densely and thinned to a spacing of 10-15 cm between plants. The leaves are alternate along the stem on short petioles, subtended by two erect, narrow, pointed stipules. The lamina is 5-12 cm long, broad at the base but tapering gradually to a pointed tip, with serrated edges; the lower most teeth of the leaf margin drawn out into fine, long, pointed auricles (Fig. 12.5)

Fibre:

Both the species differ in their yield and quality of fibre. The fibre of C. olitorius is finer, softer, stronger and more lustrous than that of C. capsularis. The colour of the fibre produced by C. olitorius is yellowish reddish or greyish depending upon the nature of the retting water, but in case of C. capsularis it is white, and that is why this species is called “white jute”.

The fibre are rotted out by submerging the plants in water. This process is called retting. As a result of enzymatic activity calcium pectate binding the cells gets dissolved and the fibres are removed by hands easily. The retting needs 10-15 days during July, while about 21 -30 days during September or afterwards. Most of the defects in fibre quality are due to incomplete or faulty retting. As soon as retting is complete, fibres must be extracted as early as possible by pressing the plants between thumb and finger. Any delay in extracting fibres results in a poor quality fibre.

Uses:

The fibers is used for manufacturing packing cloth, hessian and bags for the transport and storage of cotton, wool, foodgrains, sugar, pulses, etc. Jute is also used for making rugs, carpets, curtais, upholstery, linings, ropes and twines. Green leaves of C. olitorius are edible. Stalks stripped of fiber are used as fuel and for making gunpowder charcoal.