Cotton Cultivation in India

Cotton is the most important fibre crop not only of India but of the entire world. It provides the basic raw material (cotton fibre) to cotton textile industry.

Its seed (binola) is used in vanaspati industry and can also be used as part of fodder for milch cattle to get better milk.

CONDITIONS OF GROWTH

Cotton is the crop of tropical and sub-tropical areas and requires uniformly high temperature varying between 21°C and 30°C. The growth of cotton is retarded when the temperature falls below 20°C. Frost is enemy number one of the cotton plant and it is grown in areas having at least 210 frost free days in a year.

The modest requirement of water can be met by an average annual rainfall of 50- 100 cm. However, it is successfully grown in areas of lesser rainfall with the help of irrigation. About one-third of the total area under cotton cultivation is irrigated. In the year 1988-89 an area of 24 77 lakh hectares out of a total of 73.43 lakh hectares i.e. 33.73 per cent of the total area under cotton was irrigated.

About 80 per cent of the total irrigated area under cotton is in Punjab, Haryana, Gujarat and Rajasthan. Moist weather and heavy rainfall at the time of boll-opening and picking are detrimental to cotton as the plant becomes vulnerable to pests and diseases. High amount of rainfall in beginning and sunny and dry weather at ripening time are very useful for a good crop.

Cotton is a kharif crop which requires 6 to 8 months to mature. Its time of sowing and harvesting differs in different parts of the country depending upon the climatic conditions. In Punjab and Haryana it is sown in April-May and is harvested in December-January that is before the winter frost can damage the crop.

In the peninsular part of India, it is sown upto October and harvested between January and May because there is no danger of winter frost in these areas. In Tamil Nadu, it is grown both as a kharif and as a rabi crop.

Here the rainfall occurs after September and cotton is sown in October. The irrigated crop is sown in January-February. Most of the crop is grown mixed with other kharif crops such as maize, jowar, ragi, sesamum, castor, groundnut and some vegetables.

Cotton cultivation is closely related to deep black soils (regur) of the Deccan and the Malwa Plateaus and those of Gujarat. It also grows well in alluvial soils of the Satluj-Ganga Plain and red and laterite soils of the peninsular regions. Cotton quickly exhausts the fertility of soil. Therefore, regular application of manures and fertilizers to the soils is very necessary.

Picking is a crucial period from the labour point of view. Since picking of cotton is not yet mechanized, a lot of cheap and efficient labour is required at this time. Normally the picking season is spread over a period of about three months.

Cotton Fibre And Plant

Cotton is one of the world’s leading agricultural crops, is plentiful and economically produced, making cotton products relatively inexpensive. The fibres can be made into a wide variety of fabrics ranging from lightweight voiles and laces to heavy sailcloths and thick-piled velveteens, suitable for a great variety of wearing apparel, home furnishings, and industrial uses. Cotton fabrics can be extremely durable and resistant to abrasion. Cotton accepts many dyes, is usually washable, and can be ironed at relatively high temperatures. It is comfortable to wear because it absorbs and releases moisture quickly. When warmth is desired, it can be napped, a process giving the fabric a downy surface. Various finishing processes have been developed to make cotton resistant to stains, water, and mildew; to increase resistance to wrinkling, thus reducing or eliminating the need for ironing; and to reduce shrinkage in laundering to not more than 1 percent. Nonwoven cotton, made by fusing or bonding the fibres together, is useful for making disposable products to be used as towels, polishing cloths, tea bags, tablecloths, bandages, and disposable uniforms and sheets for hospital and other medical uses. The world’s leading producers of cotton are China, the United States, India, Pakistan, Uzbekistan, Brazil, and Turkey. Other large producers are Australia, Greece, Syria, Egypt, and Turkmenistan.

THE COTTON FIBRE

Cotton fibres may be classified roughly into three large groups, based on staple length (average length of the fibres making up a sample or bale of cotton) and appearance. The first group includes the fine, lustrous fibres with staple length ranging from about 2.5 to 6.5 cm (about 1 to 2.5 inches) and includes types of the highest quality—such as Sea Island, Egyptian, and pima cottons. Least plentiful and most difficult to grow, long-staple cottons are costly and are used mainly for fine fabrics, yarns, and hosiery. The second group contains the standard medium-staple cotton, such as American Upland, with staple length from about 1.3 to 3.3 cm (0.5 to 1.3 inches). The third group includes the short-staple, coarse cottons, ranging from about 1 to 2.5 cm (0.5 to 1 inch) in length, used to make carpets and blankets, coarse and inexpensive fabrics, and blends with other fibres.

Most of the seeds (cottonseed) are separated from the fibres by a mechanical process called ginning. Ginned cotton is shipped in bales to a textile mill for yarn manufacturing. A traditional and still common processing method is ring spinning, by which the mass of cotton may be subjected to opening and cleaning, picking, carding, combing, drawing, roving, and spinning. The cotton bale is opened, and its fibres are raked mechanically to remove foreign matter (e.g., soil and seeds). A picker (picking machine) then wraps the fibres into a lap. A card (carding) machine brushes the loose fibres into rows that are joined as a soft sheet, or web, and forms them into loose untwisted rope known as card sliver. For higher-quality yarn, card sliver is put through a combing machine, which straightens the staple further and removes unwanted short lengths, or noils. In the drawing (drafting) stage, a series of variable-speed rollers attenuates and reduces the sliver to firm uniform strands of usable size. Thinner strands are produced by the roving (slubbing) process, in which the sliver is converted to roving by being pulled and slightly twisted. Finally, the roving is transferred to a spinning frame, where it is drawn further, twisted on a ring spinner, and wound on a bobbin as yarn.

Faster production methods include rotor spinning (a type of open-end spinning), in which fibres are detached from the card sliver and twisted, within a rotor, as they are joined to the end of the yarn. For the production of cotton blends, air-jet spinning may be used; in this high-speed method, air currents wrap loose fibres around a straight sliver core.

Blends (composites) are made during yarn processing by joining drawn cotton with other staple fibres, such as polyester or casein.

The procedure for weaving cotton yarn into fabric is similar to that for other fibres. Cotton looms interlace the tense lengthwise yarns, called warp, with crosswise yarns called weft, or filling. Warp yarns often are treated chemically to prevent breaking during weaving.

CULTIVATION OF THE COTTON PLANT

The cotton plant can be found as a perennial in treelike plants in tropical climates but is normally cultivated as a shrubby annual in temperate climates. Whereas it grows up to 6 metres (20 feet) high in the tropics, it characteristically ranges from 1 to 2 metres (3 to 6.5 feet) in height under cultivation. Within 80–100 days after planting, the plant develops white blossoms, which change to a reddish colour. The blossoms fall off after a few days and are replaced by small green triangular pods, called bolls, that mature after a period of 55–80 days. During this period the seeds and their attached hairs develop within the boll, which increases considerably in size. The seed hair, or cotton fibre, reaching a maximum length of about 6 cm (2.5 inches) in long-fibre varieties, is known as lint. Linters, fibres considerably shorter than the seed hair and more closely connected to the seed, come from a second growth beginning about 10 days after the first seed hairs begin to develop. When ripe, the boll bursts into a white, fluffy ball containing three to five cells, each having 7 to 10 seeds embedded in a mass of seed fibres. Two-thirds of the weight of the seed cotton (i.e., the seed with the adhering seed hair) consists of the seeds. The fibres are composed of about 87 to 90 percent cellulose (a carbohydrate plant substance), 5 to 8 percent water, and 4 to 6 percent natural impurities.
Although cotton can be grown between latitudes 30° N and 30° S, yield and fibre quality are considerably influenced by climatic conditions, and best qualities are obtained with high moisture levels resulting from rainfall or irrigation during the growing season and a dry, warm season during the picking period.
To avoid damage to the cotton by wind or rain, it is picked as soon as the bolls open, but since the bolls do not all reach maturity simultaneously, an optimum time is chosen for harvesting by mechanical means. Handpicking, carried out over a period of several days, allows selection of the mature and opened bolls, so that a higher yield is possible. Handpicking also produces considerably cleaner cotton; mechanical harvesters pick the bolls by suction, accumulating loose material, dust, and dirt, and cannot distinguish between good and discoloured cotton. A chemical defoliant is usually applied before mechanical picking to cause the plants to shed their leaves, thus encouraging more uniform ripening of the bolls.

The Perfect Cotton Bedsheets

Think about the most comfortable bed you’ve ever slept in, and what comes to mind? If it’s the sheets, you’re in good company. Because they come in direct contact with our skin, sheets are as important as a quality mattress and cozy blanket in sending us off to dreamland.

The sheer variety of sheets on the market, however, can throw you for a loop when you’re shopping. Here are our top pointers to help you decode the labels and choose the sheets that will suit you best.

MATERIAL

Back in the day, most sheets on the market came in cotton and … cotton. And it’s still the most popular sheeting fabric, due to its durability, comfort and breathability.

Cotton both traps heat and lets cool air pass through in summer, so it’s a great choice for almost any climate. It can be blended with rayon and other materials that affect its weight and feel. As with any sheets you buy, do a hand test to gauge how you like these blends.

Egyptian, pima and Sea Island cottons are the gold standard, so look for those terms on the packaging and check to be sure the fabric is 100 percent that material. Some growers use the term “Egyptian cotton” loosely, however — true Egyptian cotton is grown and processed according to specific stipulations. Be sure you’re buying from a quality manufacturer and again, feel the material for softness.

THREAD COUNT

With all the buzz about thread count — the number of threads in 1 square inch of fabric — it’s easy to assume that higher means softer. But that’s not always the case. A lower-thread-count sheet made from fibers that are softer by nature, such as Egyptian cotton, will feel silkier than a high-thread-count sheet made from a lower-quality cotton blend.

All other things being equal, high thread counts can indeed translate to increased comfort. Don’t be tempted to buy 800- or 1,000-count sheets, however; you’ll do just fine with a style in the 400 or 450 range. The extra thread count doesn’t make enough difference in feel to justify the price. In fact, the highest-count sheets can even be stiff because so many fibers are jammed so closely together.

WEAVE

Crisp or soft? If you like your sheets with a little snap, choose percale, which is a plainer weave than the more supple sateen. Neither is inherently better; it’s a matter of personal preference.

Jersey sheets — which you probably think of as T-shirt sheets — are made with a flat knit that keeps them soft but also means they can be prone to slipping and sliding on the bed. If you live somewhere that gets extremely cold, consider nubby cotton flannel sheets, unsurpassed for keeping you toasty.

FIT

If you’ve ever tried to wrestle a too-small fitted sheet onto a mattress, you know how important it is to buy sheets that are the correct size. If you have a standard-size bed, such as a twin, queen or king, look for features such as elastic edging all the way around, which helps to ensure a smooth, snug fit.
For extra-long twin, California king, pillow-top and other nonstandard mattresses, you’ll need to look for sheets specifically marked for those sizes. If you add a foam pad or other topper to your mattress, measure the height, then buy an extra-deep sheet that corresponds. Extra-long twin sheets stretch comfortably over a mattress that accommodates taller sleepers.

And don’t forget about pillowcases: If your pillows are under- or overscale (king pillows on a double bed, for instance), buy fitted sheets, flat sheets and pillowcases as separates rather than as a same-size set.

Cotton's Major Uses

Cotton’s Major Uses

U.S. textile mills presently consume approximately 7.6 million bales of cotton a year. Eventually, about 57% of it is converted into apparel, more than a third into home furnishings and the remainder into industrial products.

Cotton’s competitive share of U.S. produced textile end-uses shows a steady increase, presently standing at approximately 34%. Cotton’s share of the retail apparel and home furnishings market has grown from a historic low of 34% in the early 1970s to more than 60% today.

Cotton is used for virtually every type of clothing, from coats and jackets to foundation garments. Most of its apparel usage, however, is for men and boys’ clothing. Cotton supplies over 70% of this market, with jeans, shirts and underwear being major items.

In home furnishings, cotton’s uses range from bedspreads to window shades. It is by far the dominant fiber in towels and washcloths, supplying almost 100% of that market. Cotton is popular in sheets and pillowcases, where it holds over 60% of the market.

Industrial products containing cotton are as diverse as wall coverings, bookbindings and zipper tapes. The biggest cotton users in this category, however, are medical supplies, industrial thread and tarpaulins.

Dyeing, Printing And Finishing

Dyeing

The most commonly used processes for imparting color to cotton are piece dyeing and yarn dyeing.

In piece dyeing, which is used primarily for fabrics that are to be a solid color, a continuous length of dry cloth is passed full-width through a trough of hot dye solution. The cloth then goes between padded rollers that squeeze in the color evenly and removes the excess liquid. In one variation of this basic method, the fabric, in a rope-like coil, is processed on a reel that passes in and out of a dye beck or vat.

Yarn dyeing, which occurs before the cloth is woven or knitted, is used to produce gingham checks, plaids, woven stripes and other special effects. Blue dyed warp yarns, for example, are combined with white filling yarns in denim construction

Printing

Printing colored designs on cotton cloth is similar to printing on paper.

Long runs of the same fabric design are produced on a roller print machine operating at speeds between 50 to 100 yards a minute. As many as of 10 different colors can be printed in one continuous operation.

A typical printing machine has a large padded drum or cylinder, which is surrounded by a series of copper rollers, each with its own dye trough and doctor blade that scrapes away excess dye. The number of rollers varies according to the fabric design, since each color in the design is etched on a separate roller. As the cloth moves between the rotating drum and rollers under great pressure, it picks up color from the engraved area of each roller in sequence. The printed cloth is dried immediately and conveyed to an oven that sets the dye

Finishing

Finishing, as the term implies, is the final step in fabric production. Hundreds of finishes can be applied to textiles, and the methods of application are as varied as the finishes.

Cotton fabrics are probably finished in more different ways than any other type of fabrics. Some finishes change the look and feel of the cotton fabric, while others add special characteristics such as durable press, water repellency, flame resistance, shrinkage control and others. Several different finishes may be applied to a single fabric.

Cotton Fabrics

Cotton Fabrics

Cotton fabrics, as they come from the loom in their rough, unfinished stages, are known as greige goods. Most undergo various finishing processes to meet specific end-use requirements.

Some mills, in addition to spinning and weaving, also dye or print their fabrics and finish them. Others sell greige goods to converters who have the cloth finished in independent plants.

Finishing processes are numerous and complex, reflecting today’s tremendous range and combination of colors, textures and special qualities.

In its simplest form, finishing includes cleaning and preparing the cloth, dyeing or printing it and then treating it to enhance performance characteristics.

To produce a smooth surface in preparation for dyeing and finishing, the greige goods are passed rapidly over gas-fired jets or heated copper plates to singe off lint and loose threads.

Moving at speeds that can be greater than 200 yards a minute, the material is scoured and bleached in a continuous process that involves the use of hydrogen peroxide. The time for the chemicals to do the preparation reactions occurs from piling the fabric on conveyor belts that pass through steaming chambers, or stacking in large steam-heated, J-shaped boxes before the goods are withdrawn from the bottom.

If a more lustrous cloth is desired, the goods are immersed under tension in a caustic soda solution and then later neutralized. The process, called mercerizing, causes the fiber to swell permanently. This gives the fabric a silken sheen, improves its strength and increases its affinity for dye. Mercerizing also can be done at the yarn stage.

Fabric Manufacturing And Processing

Fabric Manufacturing

Cotton fabric manufacturing starts with the preparation of the yarn for weaving or knitting. Annually, textile mills in the U.S. normally produce about eight billion square yards each of woven and three billion square yards of knitted cotton goods.

 

Woven Fabrics

Weaving is the oldest method of making yarn into fabric. While modern methods are more complex and much faster, the basic principle of interlacing yarns remains unchanged.

Traditionally, cloth was woven by a wooden shuttle that moved horizontally back and forth across the loom, interlacing the filling yarn with the horizontally, lengthwise warp yarn. Modern mills use high-speed shuttleless weaving machines that perform at incredible rates and produce an endless variety of fabrics. Some carry the filling yarns across the loom at rates in excess of 2,000 meters per minute.

The rapier-type weaving machines have metal arms or rapiers that pick up the filling thread and carry it halfway across the loom where another rapier picks it up and pulls it the rest of the way. Other types employ small projectiles that pick up the filling thread and carry it all the way across the loom. Still other types employ compressed air to insert the filling yarn across the warp. In addition to speed and versatility, another advantage of these modern weaving machines is their relatively quiet operation.

There are three basic weaves with numerous variations, and cotton can be used in all of them. The plain weave, in which the filling is alternately passed over one warp yarn and under the next, is used for gingham, percales, chambray, batistes and many other fabrics.

The twill weave, in which the yarns are interlaced to form diagonal ridges across the fabric, is used for sturdy fabrics like denim, gabardine, herringbone and ticking.

The satin weave, the least common of the three, produces a smooth fabric with high sheen. Used for cotton sateen, it is produced with fewer yarn interlacings and with either the warp or filling yarns dominating the “face” of the cloth.

In some plants, optical scanners continuously monitor fabric production looking for flaws as the cloth emerges from the weave machine. When imperfections appear, computers immediately print out the location of the flaw so that it can be removed later during fabric inspection.