COTTON

• Botanical name: Gossypium spp.• Vernacular name : Kapas• Family : Malvaceae

INTRODUCTION

• Cotton is the most important and oldest fiber of the world. The existence of cotton is found in Rig Veda written around 1500 BC. India remained the chief producer of cotton until 1500 AD. Dacca muslin was famous world over for its fineness .Cotton was introduced from India to other parts of the world. Cotton is now cultivated in all parts of the world.

BOTANICAL CHARACTERISTICS

• Cotton is a perennial shrub attaining a height of 1 -2 meter. The leaves are simple and palmately lobed. Stipules are free lateral. The flowers are solitary axillary , regular and bisexual . They are large and showy with yellow corolla .Sepals are persistent. The corolla has five petals with monadelphous , epipetalous stamens. The gynoecium is pentacarpellary with a superior ovary and axile placentation. The fruit is a locullicidal capsule. It is commonly called as cotton ball.

Cotton producing areas

• Cotton is a tropical crop and grows at an altitude of 900 meters above sea level. The plant requires a frost free season os 200 days , abundance of sun shine , warm and uniform temperature not below 21 degree C and above 44 degree C. and a anuual rain fall of 75 -250 cm. A relatively drier season is required during flowering. There should be no rain at the time of fruiting and ripening. (Contd.)

• Cotton is grown in a variety of soils such as Indo gangetic alluvium , black cotton soil , and lateritic soil containing a good proportion of humus. Nearly 85% of cotton comes from Russia , U.S.A. , China India , Pakistan , Brazil, Mexico , Egypt etc. India is the second largest producer of cotton in the world. The cotton procing states in India are Gujarat , Karnataka , M.P., Punjab , A.P. , Tamil nadu , Rajasthan and Haryana. But major production of cotton comes from Gujarat state.

CULTIVATION AND HARVESTING

• Cultivation of cotton varies from place to place. In india it is mainly a kharif crop. Sowing is done in June or July. For sowing of cotton field is ploughed 2 – 3 times and seeds are sown either bu broadcasting or in suitably placed rows. Proper care is taken to remove all the weeds from the field at the time of sowing as well as during the entire life of the crop. Application of Nitrogen fertiliser or farm yard manure helps in healthy growth of the crop plants , thereby increasing yield. When th plants are about 1 meter in height the apical buds are removed to induce branching.

CULTIVATION AND HARVESTING Contd.

• Flowering usually starts after 60-75 days after sowing and lasts for 8-10 weeks. The crop is harvested in three or four spells as the balls mature. For good harvesting leaves are defoliated by the application of calcium cyanamide . The fuzzy seeds are separated from the balls in the field.

KINDS OF COTTON

• All cultivated cotton belong to the four species namely G. arboreum , G. herbaceum , G. hirsutum , and G. barbadense.

Gossypium arboreum

• G. arboreum (N=13) is commonly called as Ceylon cotton , Deshi cotton , Tree cotton and old world cotton. This is probably the native to Indo – China is largely cultivated in India , Burma , Malaysia , China ,Japan etc. India and Africa are the largest producer of this cotton. This cotton plant is a perennial shrub and reaches up to a height of 3 meters. Seeds are covered with greyish green or rust colored short fuzzy hairs.

Gossypium herbaceum

• G. herbaceum (N=13) is also called as Levant cotton , uppam cotton or old world cotton. This probably the native of tropical Africa is widely grown in Africa , middle east , central Asia , western India , Iran , Afghanistan and Russia.The plants are 1.5 meters in height with three to five lobed leaves.The seeds bear two coats of hairs – long lint hairs(floss) and short fuzz (linter).

Gossypium hirsutum

G. hirsutum

• N=26. This species originated in Guatemala or Mexico. This is also called as American cotton , new world cotton , upland cotton , or bourbon cotton. This species is largely grown in USA.and accounts for the more than 35% of total world production. This cotton is also grown in South Brazil , Uganda , Iraq , India and Pakistan.The plant is a small shrub and the seeds are covered with white fuzzy coating all around.

Gossypium barbadense

• G. barbadense (N= 26) is sea island cotton ,Egyptian cotton , new world cotton or Kidney cotton. The species is native to tropical south America(Brazil) and is highly esteemed for the length and fineness of its lint. The lint is pure white in color.

• 1. Egyptian cotton: Grown in Egypt , Sudan South America etc. gives a high quality cotton primarily for the use of Automobile tyres.

• 2.Sea island cotton: It is cultivated in west indies and Fizi. Fibers are very long and lustrous and used in the manufacture of laces , and fine textiles.

PROCESSING OF COTTON

• 1.Ginning• 2.Bailing• 3.Picking• 4.Carding• 5.Combing and drawing

GINNING

• In this process capsule walls .soil etc are removed from the cotton ball in a machine called Gin.

BAILING• In this process the cotton obtained from the

gin is packed into bales by a hydraulic machine. Each bail weights about 500 lb. Bails are transported to the cotton mills.

PICKING

• In the mill cotton is beaten so that they are free from foreign matters. This cotton is now called as sheet or lap cotton.

CARDING

• In this process the remaining lumps are further separated so that immature fibers and impurities are removed.

COMBING AND DRAWING

• In combing short fibers are separated while long fibers are straightened.

• Cotton thus obtained is in the form of soft thin sheet and ready for spinning.

CHARACTERISTICS OF COTTON FIBERS

• Cotton fibers are epidermal hairs present on the seed coat. The mature cotton fiber is translucent with collapsed hollow tube. The primary wall of the cotton fiber is thin , elastic and coated with chitin. The secondary thickenings are in the form of concentric rings. The raw cotton contains 94% cellulose , 3% proteins , 0.9% pectin , 0.6 % wax< 0.3% sugars and 1-2% ash. Fibers are classified on the basis of their length as long , intermediate and short fibers.

USES OF COTTON

• Cotton fibers are used in:• 1. Cloth , tyre fabrics , various forms of threads

etc. • 2. Mercerized cotton is obtained by treating

cotton fibers with caustic soda.• 3.Absorbant cotton is produced after removing

the chitin layer of the fibers.It is used in hospitals , rayon industry , explosive factories etc.

• 4.Cotton is used extensively for stuffing.

• 5. Cotton seed is rich in Vitamin B complex and proteins.

• 6. Cotton oil is used in culinary.• 7.The oil cake is an fertilizer and cattle feed.

THANKS