In this article we will discuss about:- 1. Origin and History of Cotton 2. Production Characteristics of Cotton 3. Classification 4. Zones 5. Growth and Development 6. Quality Parameters 7. Facts.
Origin and History of Cotton:
Fortunately, it is easier to trace the history of cotton from the first century onwards when Arab traders brought it to Europe. By the 9th century, the Moors had started cultivating it in Spain and when Columbus reached America in 1492, he found quantities of cotton growing in the Bahama Islands.
By 1500, the world knew all about cotton, including its various uses and benefits. It took another 200 odd years for it to be first spun by machinery, in England in 1730. This, together with the invention of the cotton gin in the United States, made cotton what it is today – not just one of the world’s favourite fabrics but also one of the biggest global money-spinning cash crops of all times.
Cotton also enjoys a rich cultural and social-economic history. Many a country rose and fell on the strength of what we often call “just fluff”. In Peru, the cotton fibre grown was the backbone of the development of coastal cultures such as Norte Chico, Moche and Nazco. In the UK and much of Europe, cotton textiles were the leading exports for more than a century.
In the United States, the quantities of cotton grown fuelled the country’s development throughout most of the 19th century to the mid-20th century. Today more than 80 countries grow cotton – India is one of the largest – and each one has its own cotton history to tell. Cotton finds mention in the Rig-Veda, the oldest scripture of the Hindus and Manu’s Dharma shastra.
In India it has had the pride place among the cash crops from the earliest times. India was having a flourishing export trade in cotton and cotton goods as early as 569-525 B.C. One of the army generals of Alexander the Great, during his sojourn in India described cotton as a plant from which the natives plucked the vegetable wool which they spun in to admirable clothing.
Yet cotton seems to grow younger day by day. With changing times, and the turn of the season, cotton seems to rejuvenate and reinvent itself as the much-loved fabric that breathes more than just comfort and contemporary life. It is the yarn that weaves the fabric of style.
The genus Gossypium is placed in Malvaceae family, tribe Gossypiae because of the uniqueness of lysigenous glands found throughout the species within the genus. These glands contain a number of sesquiterpenes, collectively called gossypol. The genus Gossypium comprises 49 species, of which 4 are commercially grown for lint and seed purposes.
Among them, two each are diploids and alio tetraploids species. The 2 diploid species (2n = 26) are known as old world or Asiatic cottons (in India, they are called deshi cottons). Gossypium arboreum L. also called tree cotton is cultivated in India and G. herbaceum L. called Arabian/Syrian cotton is cultivated in central Asia. The other 2 species called new world cottons are American or upland cottons (G. hirsutum L.) and Egyptian or sea island cottons (G. barbadense L.).
G. arboreum has originated in the Indo-Gangetic alluvium of north India. The cultivated G. herbaceum derived from G. herbaceum var. africanum (distributed in South Africa). G. hirsutum is native to Mexico and Central America, while G. barbadense has originated from South America (probably Peru).
Cotton has been used as a fabric in India since time immemorial. It has been cultivated in the Indus valley more than 5000 years. The excavation of Mohenjo-Daro indicates high degree of art in spinning and weaving with cotton at that time. India is considered as a center of an important cotton industry as early as 1500 BC. The cultivation of cotton spread from India to Egypt and then to Spain and Italy.
Cotton is the most important vegetable fibre crop of the world cultivated over an area of 35.2 million ha with a total production of 69.9 million tonnes and a productivity of 1.98 t/ ha of seed cotton. The important cotton growing countries are India, China, USA, Pakistan, former USSR, Brazil. Mexico, Turkey, Egypt and Sudan, accounts for nearly 85 % of the total cotton production.
Production Characteristics of Cotton:
The planting period in India takes places from March to September while harvesting takes place from October to February. Cotton is produced in three zones, the Northern zone comprising the states of Punjab, Haryana and Rajasthan, the Central zone comprising the states of Maharashtra, Madhya Pradesh and Gujarat and the Southern zone comprising the states of Andhra Pradesh, Karnataka and Tamil Nadu. Besides these 9 states, cotton cultivation is gaining momentum in the state of Orissa. About 70% of total cotton production is accounted by the states of Gujarat, Maharashtra and Andhra Pradesh.
India has the largest area devoted to cotton cultivation (9.4 million hectares in 2008/09) with an estimated 4 million farms. Approximately 65% of India’s cotton is produced on rain-fed areas. India is the only country to grow all four species of cultivated cotton Gossypium arboreum and herbaceum (Asian cotton), G.barbadense (Egyptian cotton) and G. hirsutum (American upland cotton). Gossypium hirsutum represents 90% of the hybrid cotton production in India. India produces a large number of cotton varieties and hybrids.
Though the number of varieties in cultivation exceeds seventy-five, 98% of the production is contributed by about 25 varieties. The rapid growth in yields (between 2002/03 to 2007/08) is attributed to the introduction and expansion of biotech cotton and improved hybrid cotton varieties, improved crop management practices and overall favorable weather conditions in most of the states involved.
According to recent studies, with the area under biotech cotton and improved varieties nearly peaking, the prospect for future growth in productivity is limited as most cotton is grown under rain fed conditions and on land holdings of small size.
Although the potential exists for a further increase in yields, cotton farmers will have to invest more in production technologies for improved management of irrigation, fertilizers, micro nutrients and pests and diseases, i.e., move toward precision farming.
The Indian government actively participates in the industry and serves as an umbrella for government agencies like Cotton Corporation of India (CCI) and state marketing federations. Furthermore, the state governments and regions in which the majority of the cotton planting occurs are also highly involved. In addition, there are committees and institutions responsible for the improvement of quality such as Genetic Engineering Approval Committee (GEAC) and the Central Institute of Cotton Research (CICR).
Classification of Cotton:
The genus Gossypium includes 49 species of cotton including wild as well as cultivated species. The cultivated species have spinable lint, while wild species have only short seed fuzz or smooth seeds. Out of the total species, only 4 are cultivated, of which 2 are diploids (deshi) and two tetraploids (American cottons).
1. Gossypium arboreum (n = 13) – Deshi/Asiatic cottons – It is most widely grown deshi cotton. The lint is short (staple length <25 mm) and coarse with micronaire value >60.
2. Gossypium herbaceum (n = 13) – Deshi / Asiatic cottons – It is less widely grown. These two species accounts for nearly 2% of world cotton production. In India, they account for 28% of the cotton acreage.
3. Gossypium hirsutum (n = 26) – American or African upland cotton – These are medium staple (staple length 25-30 mm) cottons with micronaire value ranging from 3.8- 5.0. It accounts for over 90% of global cotton production.
4. Gossypium barbadense (n = 26) – Egyptian cottons – The fibre length is long (staple length .32 mm) and fine with micronaire value of < 4.0. It accounts for about 8% of global cotton production.
Cotton Zones of India:
India is divided into 3 cotton zones based on species grown as below:
1. Northern hirsutum, arboreum and hybrid zone – In this zone short (<20 mm) and medium staple (>20.5 -25.5 mm) cotton is cultivated under irrigation.
2. Central hirsutum, herbaceum, arboreum and hybrid zone – In this zone medium (26.0-27.5 mm) and long staple (28.0-33.5 mm) cotton is cultivated under rain fed situation.
3. Southern arboreum, hirsutum, herbaceum, barbadense and hybrid zone – In this zone long (28-33.5 mm) and extra-long staple (>35 mm) cotton is cultivated under irrigated or rain fed situations.
The fruiting limb or sympodium, having flower buds called squares. It is natural for some squares, blooms and small bolls to be shed. Moisture deficiency or excess, inadequate number of fertilized ovules, insufficient nutrient supply, high or low temperature and damage from insect-pests increases boll shedding in cotton. Excessive vegetative growth some time creates imbalance in distribution of photosynthate from source to sink resulting in boll shedding.
There are several theories to explain flower and boll shedding. Nitrogen theory exhibits that a normal leaf contains 5% nitrogen and drops to 2.5% as crop heading towards reproductive stages. Internal retranslocation of N sometimes leads to boll shedding. A balanced C: N ratio is required for better boll or flower retention. Nutritional theory suggests that plant growth is limited by carbohydrates and nutrient supply. High carbohydrate accumulates 10 days after flowering.
However, if the carbohydrate production is limited during the heavy boll load of the plant, boll shedding may occur. Nutrient diversion theory indicates that hormones and inhibitors interact with the supply of photosynthates, thus controls growth and fruit development. Cytokinin produced in roots if counteract with ABA (abscisic acid) effect, then the counteract process promotes nutrition diversion to the sink, thereby help boll retention. On the contrary if the cytokinin counter action is ineffective boll shedding will be increased.
Spraying of hormones such as NAA @ 40 ppm preferably in the evening time during 60-90 DAS reduce the physiological flower/boll shedding, improves the boll setting and seed cotton yield. Proper water management, adequate drainage and balance fertilization will also reduce boll shedding.
The malady of bad boll openings, commonly referred as tirak has been found in desi cotton which is mostly concerned with premature and improper cracking of bolls. Generally, the symptoms on the crop are yellowing/reddening of leaves at the beginning of reproductive stage followed by bad boll opening. The factors that cause bad boll opening are nitrogen deficiency in light soils, soil salinity or alkalinity in subsoil or very high temperature and low humidity during boll development stage.
Growth and Development (Stages of Crop Growth) of Cotton:
Germination to Emergence:
The time required for emergence depends on soil temperature. In India cotton sown in June – July takes 5 -6 days for emergence.
Emergence to Flowering:
The first cotton leaf appears 10-12 days after emergence. Leaf development reaches its peak about three weeks after the first buds are formed. The first flower bud appears on the lowest fruiting branch 35 – 45 days after emergence, depending upon prevailing temperatures.
The time taken between the appearance of first flower bud (square) and opening of the flower may be between 25 – 30 days. Squaring may be from 35- 70 DAS depending upon variety, location and management. Flowering begins at 20-35 days after first square formation and continues for 60-80 days. However, the peak flowering period varies from 7-100 DAS.
Emergence of large number of flowers is seen for certain period and there after it declines. During the peak period of flowering the vegetative growth is almost negligible and once the rate of flowering declines the vegetative growth restarts. The flowering period is reduced by late sowing, strong plant competition and moisture stress.
Strong positive correlation was observed between numbers of flowers produced and flowering period, hence the similar relation was noted between flowering period and yield. Environment and cultural practices have little influence on the time of flowering but the number of flowers can be increased by the factors favourable for growth.
Fertilization:
Fertilization takes place usually in the morning for few hours immediately after flower opening. After fertilization the flower drops at and a small boll left over. Initially the boll development is slow and later the growth rate is rapid and steady.
About 3 weeks lapses for the development of boll to full size and for maturation of fibres and seed it may take about 4 weeks. The maximum weight of the boll is normally attained by 45 – 50 days after fertilization followed by bursting of boll. The boll bursting depends on temperature and varietal character.
Seed and Fibre Development:
Fibres which formed during the first two or three days developed into lint and subsequently formed fibres are of short nature comes under the name fuzz.
Quality Parameters of Cotton Plant:
The economic product of cotton plant is seed cotton, and lint comprises the most important commercial product. Cotton quality is a varietal character. Various climatic, soil and agronomical factors influence the quality of cotton. Various characters that determine the commercial value of cotton are elucidated below.
Ginning Percentage:
Ginning is the process of separating the fibres from seed cotton. It is also known as ginning out turn and is the first processing operation conducted by ginning mills. Ginning % is the ratio of the weight of fibres to seed cotton (kapas) expressed in percentage.
The range for G. barbadense type is 28-30%, 34-38% for G. hirsutum, and 36-42% for desi type cotton.
Fibre (Staple) Length:
It is the most important quality parameter of fibres deciding their value. It is taken as arithmetic mean of the length of all fibres present in the sample.
Cottons are classified based on staple length into the following classes:
Spinning Potential:
It is measured as number of counts i.e., number of hanks (1 hnk = 840 yards) that weigh to 1 pound (lb), it varies from as low as 6 s (G.arboreum) to the highest of 120 s (G. barbadertse).
Micronaire Value:
Micronaire value is used for judging the fibre strength. It is a measure of the air permeability of a unit mass of cotton under specified conditions, expressed in terms of an arbitrary scale (micronaire scale). In immature and dead fibres it is = 2. The metric equivalent of it is tex. The units of tex are micrograms/mm of fibre length.
Seed Index:
It is the weight of 100 seeds (g) and also known as test weight. On an average the seed indices of cotton varies from 4.8 to 11.0 g depending upon the variety and management factors. It ranges from 4.8-5.0 in arboreum, 5.5-6.0 g in harbaceum, 8.0-11 g in hirsutum and 9.0-11.0 g in barbadense.
Oil Content:
This is another parameter which decides the quality and is of commercial importance. Seed oil content ranges from 14.6 to 25.6 percent. The major problem is the presence of toxic pigments such as gossypol, gossy purpurin and gossypulvin.
Facts about Cotton:
1. US paper currency isn’t paper at all… it’s a blend of 75% cotton lint and 25% linen. A 480 pound bale of cotton can be made into 313,600 $100.00 bills!
2. Sheer cotton muslin, woven in ancient India, was so fine that 73 yards of it weighed one pound!
3. In ancient Egypt, only the High Priest was allowed to wear a cotton garment.
4. Cotton is a member of the Mallow family of plants. The Arabic peoples called it “Qutun,” which is where we get the word “Cotton.”
5. Eli Whitney’s cotton gin wasn’t a new idea. The “Churka,” invented in India 3,500 years earlier, was very efficient at ginning long staple cotton but ineffective on the short staple variety. Whitney’s gin was the first gin to process short staple cotton.
6. Mills in Lancashire, England exported 7,000,000,000 yards of cotton fabric in 1913. That’s an amazing 221.97 yards per second!
7. California’s San Joaquin Valley cotton, characterized by long, strong fibers, is among the highest quality in the world.
8. Among U.S. grown varieties, California’s Acala and Pima cottons are preferred for fine fabrics and used in high quality table linens, sheets, bath towels and dress shirts, among other fabric products.
9. Between 1920 and 1922, the Boll Weevil caused cotton production in South Carolina to drop 70 percent!
10. It can take more than 20,000 litres of water to produce 1 kg of cotton; equivalent to a single T-shirt and pair of jeans. 73% of global cotton harvest comes from irrigated land.
Issues that generally plague the cotton industry are those related to the level of technology and modernization in the industry. These issues generally lead to larger problems that make the successful commercialization of cotton as a cash crop difficult.
Consequently for the majority, cotton agriculture is stuck at the subsistence level. However, this is being addressed by the Technology Mission on Cotton (launched in February 2000) which continuously aims at improving the quality and productivity of cotton.
The Mission consists of four Mini Missions focusing on research and development on cotton, dissemination of technology to the farmers, improvement of marketing infrastructure and modernization of ginning and pressing sector.
Simultaneously, workshops, seminars and public meetings are also being organized to maximize its impact by creating awareness among the cotton growers and to motivate them to follow the Best Management Practices for improving quality of cotton and reducing the level of contamination.
India grows all the four major varieties of cotton-G. Arboretum, G. hirsutum, G. herbaceum and G. barbadense. The first hybrid in the cotton crop-H4 intra hirsutum in 1970-was developed in India, in Surat, by Dr. C.T. Patel. More than 200 varieties and hybrids were evolved in the subsequent five decades. As of 1998, hybrids accounted for around 45 per cent of cotton crop in India.
Important landmarks in the Indian cotton history include the development and release of native hybrids like G. cot DH 37, G cot DH 9, DDH 2 and drought-tolerant straight varieties like SRT 1, Renuka, LRA 5166, Anjali and Rajat. Over the years, India has achieved significant increase in cotton production.
Till 1970s, the country used to import massive quantities of cotton in the range of 800,000 to 900,000 bales per annum. However, after the government launched special schemes like intensive cotton production programmes through successive five-year plans, India has achieved significant increase in cotton production.
Cotton production received the necessary impetus through increase in area and sowing of hybrid varieties around mid-70s. Since then, the country has become self-sufficient in cotton production, barring a few years in the late 90s and early 20s when large quantities of cotton had to be imported due to lower crop production and increasing cotton requirements of the domestic textile industry.
Since the launch of ‘Technology Mission on Cotton’ by the government of India in February 2000, significant achievements have been made in increasing production through development of high-yielding varieties, appropriate transfer of technology, better farm management practices, increased area under cultivation of cotton hybrids, etc.
All these developments have led to a turnaround in cotton production in the country since last few years. The yield per hectare, which had remained stagnant at about 300 kg for more than ten years, increased substantially and reached a level of 560 kg per hectare in cotton season 2007-08.
Fundamental changes taking place in cotton cultivation have the potential to take the current productivity level in India close to the world average cotton production per hectare in the near future. Apart from meeting the increased cotton consumption by the domestic textile industry, India may have sufficient surplus cotton to meet the cotton requirements of importing countries.
An increasing trend in the production of cotton from 15.8 million bales in the year 1997-98 to 31.5 million bales in the year 2007- 08, though a few years saw some fluctuations. Yield increased from 399 kg per hectare in the year 2003-04 to 560 kg per hectare in the year 2007-08.
Last four years have seen nearly 40 per cent increase in the yield of cotton. The area under cotton cultivation too increased from 7.63 million hectares in the year 2003-04 to 9.55 million hectares in the year 2007- 08-an increase of about 25 per cent. In order to produce quality cotton to suit the needs of the textile industry, the momentum on integrated cotton cultivation is gaining ground through linkages amongst all concerned.
The farmers will be expected to form associations for contract farming and textile mills and other coordinating agencies shall be entrusted all the extension including various inputs and marketing support for such cotton produce.
The scheme in its extended form is likely to benefit both the cotton growers (through low cost of production and higher productivity) and the textile mills (with availability of quality cotton comparable with international standards). If we analyse the world level, cotton consumption increased from 21.74 MMT in 2003-04 to 26.49 MMT in 2006-07 and to 26.38 MMT in 2007-08.
Domestic demand for cotton yarn is projected to grow at an annual rate of 7.3 per cent until 2011. Driven by both international demand for Indian exports and a healthy domestic market due to the increased purchasing power of the middle class, India’s export strategy is likely to continue favouring. The increasing consumption at world level and the increasing area of cultivation, production level and yield per hectare in India surely encourage our farmers to concentrate in cultivation of cotton.