Cotton is the collective name given to four species of plants in the genus Gossypium, Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum and Gossypium herbaceum which are perennial shrubs in the family Malvaceae grown for the fluffy fiber which protects the seeds of the plant. G. hirsutum accounts for approximately 90% of world-wide cotton production today. Cotton plants possess a main stem giving rise to several branches at the top. The leaves of the plant are spirally arranged on the branches, have long petioles and have 3–5 triangular lobes. The plant produces a single flower on each axillary branch which can be red-purple, yellow or white in color and forms a leathery, oval seed capsule, or ‘boll’ which is 2–6 cm (0.8–2.4 in) long. Mature bolls will usually split open to reveal the characteristic white cotton fibers and the seed. The cotton plant can reach heights of 1–1.5 m (3.3–4.9 ft) and is usually cultivated as an annual, surviving only one growing season. Cotton may also be referred to as tree cotton and its center of origin is unknown although the plant has diversified from Mexico, north-east Africa and Arabia and Australia. https://plantvillage.org/topics/cotton/infos
Cotton, being a deep rooted crop, requires well prepared seedbed. The field, after the harvest of the preceding crop, should be ploughed 15-20-centimetre-deep with mould board plough. Thereafter three or four harrowing or three to four ploughings with local plough should be given.
After each ploughing, planking is essential to make oil pulverised and levelled. No stubbles of the previous crop should be left in the field.
For irrigated crop, the field should be prepared by applying heavy pre-sowing irrigation. Two pre-sowing irrigations at short intervals are more beneficial than giving the same water in one irrigation. https://aaqua.persistent.co.in/aaqua/forum/viewthread?thread=8027
Climatic and Soil Requirement
Cotton is a Warm season (tropical) crop. It can be profitably grown in regions with rainfall of 850-1100 mm, but economic yields can not be realized in the region with a rainfall less than 500 mm.50cm of well-distributed rainfall is necessary for higher yields. In general, temperatures above 35-degree C are not desirable for cotton growing, however, when the moisture supply is favourable, the cotton plant is capable of enduring without permanent injury, very high temperatures (upto 43-45-degree C) for short periods. If these high temperatures persist for several days, however, the yields will be adversely affected. High light intensities throughout the growing period are essential for satisfactory vegetative development, for minimal shedding of buds and bolls and hence for higher yields. Cotton Crop can be grown up to 1000m altitude
Cotton has a wide range of soil adaptation and is grown on a great variety of soils. Highest yields of cotton are usually obtained on alluvial soils. High yield of cotton is dependent on favorable air and moisture regime in the soil-hence the importance of soil structure and texture. For a deep-rooting crop such as cotton, soil depth is also an important factor and shallow soils are not suitable. Cotton is not unduly sensitive to soil reactions; it can be grown on a variety of soils with pH ranging from 5 to 8 and above. Cotton is generally considered as fairly tolerant to salinity. Uptake of Sodium by cotton has been found to be much lower than would be expected from its relative abundance and availability in soil and water as was shown by the low accumulation of sodium in both tops and roots. This indicates that the relatively high salt-tolerance of cotton may be at least party due to the presence of some selective mechanism that enables cotton roots to restrict sodium absorption. With irrigation facilities, cotton is usually cultivated on sandy loam to loam soils. http://textilesindepthcom.typepad.com/cotton_crop_and_cotton_in/2010/09/climatic-requirements-for-cotton-crop.html
|Season and Varieties|
I. SEASON AND VARIETIES
II. PARTICULARS OF COTTON VARIETIES/HYBRIDS
II. PARTICULARS OF COTTON VARIETIES/HYBRIDS (CONTD…)
Planting Population/Seeding Rate
Proper spacing of cotton plants can help maximize yield potential. Planting cotton seed at too high of a population can cause overcrowding of plants and may unnecessarily increase seed cost. A final stand of 2.5 plants per row foot will typically help maximize yield potential.
High plant populations should be avoided unless very aggressive management practices are to be used in combination with proper variety selection. When cotton plant populations are too high, the following can occur:
Later initiation of fruiting with a somewhat shortened boll loading period due to running out of time at the end of the season.
Decreased drought tolerance.
Increased fruit shedding due to difficult to control plants during the mid to late season.
Increased need for more aggressive PGR use during the cropping season.
Increased number of small bolls.
Plant populations that are too low can also reduce yield potential. Reduced cotton stands can:
Increase plant size.
Delay reproductive development. Low populations typically fruit earlier but require time to accumulate a fruit load that allows for optimal yield. All of this takes time, which may or may not be beneficial, and can add management challenges in late planting and short-season scenarios.
Shift more bolls to outer fruiting branches and vegetative branches.
Increase boll size and micronaire at some fruiting positions.
Several local conditions can influence the need to adjust cotton planting populations depending on management system/style, variety characteristics, projected weather patterns, and planting date. Some of these specific conditions include:
Early planting. A challenge of early planting is often on the ability to establish and maintain an adequate stand in the face of seedling disease, cold weather, and generally difficult establishment conditions. In the case of early planting into adverse conditions, populations should be increased to compensate for potential losses.
Late planting and/or dryland production. This scenario includes any case where earliness is at a premium. Cotton planted behind wheat or in the last quarter of the planting cycle falls generally into this category. In cases where earliness is required, planting higher populations, in combination with aggressive in-crop management can help make the crop earlier while maintaining adequate yield potential. Having more plants in the field allows a relatively high level of yield accumulation in shorter periods of time as compared to less dense stands. This ultimately allows for an earlier crop to be harvested.
Planting on “growth 65533;? soil types. Highly productive soils that have demonstrated the need for aggressive growth control in the past can often benefit from decreasing the planting populations versus the previous experience. Fewer plants generate less competition for resources and thereby usually require less growth control.
High input, high yield environments. These production environments require the most aggressive decision making, management inputs, and carry somewhat higher risk. In this scenario, we generally plant populations that are above average for a region. These fields are typically irrigated and are very aggressively managed with PGRs, fertility, and irrigation applications. These factors influence the likely outcome of a crop in any field, but in this environment, having relatively high numbers of surviving plants establishes the yield potential early in the season. It also carries somewhat more risk but can be managed if those risks are acknowledged up front starting with planting rates and continuing with in-season management decisions.
Setting a target final stand can be accomplished by figuring a targeted seed per foot or plants per acre. Seeding rates can be adjusted by slightly lowering them as the weather conditions and forecast move toward the ideal, which can be achieved under irrigation and high temperatures.
Table 1. Seed drop rates for desired plants per foot of row.
|Row Width||2 seed/ft||2.5 seed/ft||3 seed/ft||4 seed/ft|
Cotton is typically raised in 38- or 40-inch raised beds in many southern regions; however, some growers plant in narrower 30-inch, 2:1 skip rows. A narrow row planting system allows the use of the same 30-inch planter for cotton, corn, soybean, and other row crops.
Some row spacing research indicates that narrowing row width to 30-inches can increase yield potential. Closer row spacing can help the crop canopy close early in the season. Earlier canopy closure in 30-inch rows may help the cotton crop mature a few days earlier than cotton grown in 38-inch rows. Narrow row spacing can also be more efficient in the use of solar radiation for the photosynthesis process. Cotton grown in narrow rows may require more intensive management as the plants can demand increased nutrients and may produce more vegetative growth, potentially requiring additional plant growth regulator applications. http://www.aganytime.com/Cotton/Pages/Article.aspx?article=128
|Cultural Practices||Northern cotton zone||Central cotton zone||Southern cotton zone|
|Fertilizers||N – 60 – 100 kg / ha.
P and K dose as per soil test.
No P need be applied if previous wheat received / recommended P does 5.5 kg.Zn / ha. as ZnSo4 once in two cotton – wheat cycles
| N : P : K 40 – 20 – 20, 50 – 25 – 25, 80 – 40 – 40 for varieties
100 – 50 – 50, 160 – 80 – 80, 240 – 120 – 120, for hybrids
| N : P : K 40 – 20 – 20,60 – 30 – 30, 90 – 45 – 45 for varieties
100 – 50 – 50, 120 – 60 – 60, 150 – 60 – 60 for hybrids
|Method of fertilizer application||i) Half N at thinning and remaining at first flowering;
ii) Half N at sowing time in late sown crop;
iii) Foliar application of N if needed;
P to be drilled at sowing.
|N in three splits at sowing, squaring and peak flowering stages. ( P & K according to soil test). Application of 2 % urea or DAP at flowering and early boll development.||N at squaring and peak flowering, P & K at sowing. In Karnataka entire NPK at planting ( rain fed cotton ), Half N and entire P & K planting, remaining N at flowering (irrigated cotton ) N in 4 splits in irrigated hybrid cotton.|
|Bio – fertilizer||Seed treatment with azotobacter is beneficial.
|Seed and soil treatment with Azospirillium in Tamil Nadu.
Pest and Diseases Management
Common Pests and Diseases
Bacterial blight/angular leaf spot of cotton
Xanthomonas axonopodis pv. malvacearum
Earlier Xanthomonas citri ssp. malvacearum
Angular leaf spot of cotton symptoms
Spots on infected leaf
Lower surface of infected leaf
water soaked spot
Water-soaked spots on leaves which are delimited by leaf veins, giving them an angular appearance; lesions increase in size and turn black and necrotic; leaves drop from the plant; disease may also cause elongated gray-black lesions extending from the leaves to petioles and stem which are known as the “blackarm” phase; severe blackarm symptoms may cause the stem to be girdled; water-soaked lesions may be present on bolls; boll lesions enlarge and become sunken and brown-black in color.
Disease if often introduced to cotton fields by infested seeds.
The use of resistant cotton varieties is the most effective method of controlling the disease; cultural practices such as plowing crop residue into soil after harvest can also limit disease emergence.
Discoloration of vascular tissue caused by Fusarium wilt
Discoloration of vascular tissue caused by Fusarium wilt
Wilting of cotyledons and seedling leaves; cotyledons become chlorotic at the edges and then necrotic; older plants exhibit symptoms of wilting and leaf chlorosis; wilting is usually gradual but may be pronounced after heavy summer rain; if infection is severe plants become stunted and may be killed; vascular system of infected plants becomes discolored and can be seen by cutting the stem.
Disease emergence is favored by warm temperatures; fungus may be introduced to field through infected seed or by contaminated equipment and human movement.
Use on certified, disease-free seed; plant varieties with higher resistance to the disease in areas with a history of Fusarium diseases; fumigating the soil may reduce disease incidence.
Alternaria leaf spot
Small, circular brown lesions on cotyledons and seedling leaves which expand and develop a concentric pattern; necrotic areas coalesce and often have a purple margin; centers of lesions may dry out and drop form the plant creating a “shot-hole” appearance on the leaves.
Plants stressed by drought, nutrient deficiency and other pests are more susceptible to the disease; fungus spreads rapidly in dense canopies, especially during periods of warm, wet weather.
Plow crop residue into the soil to reduce inoculum levels; provide plants with adequate irrigation and nutrients, particularly potassium; applications of appropriate foliar fungicides may be required on susceptible cultivars.
Cercospora leaf spot
Circular red lesions on leaves which enlarge and turn white or gray in the center; lesions often have a pattern of concentric rings and possess a red margin; dark gray spore masses form in the centers of the lesions making them appear dark gray.
Fungus overwinters in crop debris from previous growing season; commonly found alongside Alternaria leaf spot and other foliar disease.
Plough crop residue into the soil to reduce inoculum levels; provide plants with adequate irrigation and nutrients; applications of appropriate foliar fungicides may be required on susceptible cultivars.
Symptoms of Asochyta blight on cotton foliage
Ascochyta blight of cotton
Symptoms of Asochyta blight on cotton foliage
Damage to cotton seedling.
Symptoms of Asochyta blight on cotton foliage
Symptoms on lower leaf surface
Brown or gray spots on leaves surrounded by a red halo; elongated red-purple cankers on stems cause the wilting and death of leaves above.
Disease emergence is favored by cool, wet weather.
No fungicides are currently registered for use in cotton; plow crop debris into soil after harvest; crop rotation has little to no effect of control of disease.
Target leaf spot
Spots on infected leaves
Circular to irregular spot with target markings
Corynespora leaf spot (Corynespora cassiicola)
Symptoms on infected leaf
The symptoms can be found on leaves, boll bracts and on bolls. Initially the appearance of small chocolate brown spots which later enlarge to become circular to irregular spot with target markings. The symptoms are mainly seen in the lower canopy. Typically, the infected leaves retain their green color or green yellow color. Under severe conditions leaf and flower drop may occur.
The pathogen also infects cucumber, sweet potato, soybean and tomato. It will cause severe loss if pathogen infect at flowering stage. The disease is common in Southeastern cotton producing states of USA. The target spot is confused with leaf spot caused by Cercospora spp. Stemphyllium spp. or Alternaria spp. But this spot is surrounded by reddish to purplish margin.
Use available resistant varieties. Follow crop rotation. Spray suitable fungicide.
Cutworms (Black cutworm, Variegated cutworm)
Variegated cutworm (Peridroma saucia) larvae
Larvae of variegated cutworm
Back cut worm larvae
variegated cutworm (Peridroma saucia) adult
Black cutworm (Agrotis ipsilon) adult
Larvae of black cutworm
Adult variegated cutworm
Adult black cutworm
Stems of young seedlings may be severed at soil line; larvae causing the damage are usually active at night and hide during the day in the soil at the base of the plants or in plant debris of toppled plant; larvae are 2.5–5.0 cm (1–2 in) in length; larvae may exhibit a variety of patterns and coloration but will usually curl up into a C-shape when disturbed.
Insects outbreak favored by a cool, wet spring following a mild winter; cutworms have a wide host range and attack vegetables including asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato and tomato.
Remove all plant residue from soil after harvest or at least two weeks before planting, this is especially important if the previous crop was another host such as alfalfa, beans or a leguminous cover crop; plastic or foil collars fitted around plant stems to cover the bottom 3 inches above the soil line and extending a couple of inches into the soil can prevent larvae severing plants; hand-pick larvae after dark; spread diatomaceous earth around the base of the plants (this creates a sharp barrier that will cut the insects if they try and crawl over it); apply appropriate insecticides to infested areas of garden or field if not growing organically.
Aphids (Cotton aphid)
Sooty mold on open cotton resulting from aphid infestation
Honeydew and damage
cotton aphid infestation
Cotton aphids nymphs and adults
Cotton aphid (Aphis gossypii) infestation
Honeydew on leaves due to aphid infeataion
Aphids are eating by lady bird beetle larvae
Infestation on tender shoot
Adult winged form
Cotton aphid infestation
Cotton aphid (Aphis gossypii)
Aphids on cotton leaves
Biological Control: Aphids with lady beetle larva predator
Leaf curling downward due to feeding
Small soft bodied insects on underside of leaves and/or stems of plant; usually green or yellow in color, but may be pink, brown, red or black depending on species and host plant; if aphid infestation is heavy it may cause leaves to yellow and/or distorted, necrotic spots on leaves and/or stunted shoots; aphids secrete a sticky, sugary substance called honeydew which encourages the growth of sooty mold on the plants.
Honeydew excreted by aphids promotes growth of mold. This honeydew also attarcts ants which then protect the aphids from natural enemies and even move aphids to other parts of the plants and even other plants.
If aphid population is limited to just a few leaves or shoots then the infestation can be pruned out to provide control; check transplants for aphids before planting; use tolerant varieties if available; reflective mulches such as silver colored plastic can deter aphids from feeding on plants; sturdy plants can be sprayed with a strong jet of water to knock aphids from leaves; insecticides are generally only required to treat aphids if the infestation is very high – plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use.
Larvae feeding on cotton square
Hole under cotton bloom due to bollworm
Cotton bolls damage by the cotton bollworm
Egg of cotton bollworm
Hole due to larvae feeding
Numerous cotton bolls and squares damage by an overwhelming population of cotton bowlworms
Bollworm larvae feeding on cotton bloom
Damage due to bollworm
Adult moth of Helicoverpa zea
Late instar larvae feeding on cotton square
Cotton bollworm feeding on a cotton bloom
Egg of bollworm on cotton leaf
Feeding on boll
Late instar larvae feeding
Holes chewed in bases of bolls and insect frass around holes; Young caterpillars are cream-white in color with a black head and black hairs; older larvae may be yellow-green to almost black in color with fine white lines along their body and black spots at the base of hairs; eggs are laid singly on both upper and lower leaf surfaces and are initially creamy white but develop a brown-red ring after 24 hours and darken prior to hatching.
Adult insect is a pale green to tan, medium sized moth; insect is also very damaging pests of corn; insect overwinters as pupae in the soil.
Monitor plants for eggs and young larvae and also natural enemies that could be damaged by chemicals; Bacillus thuringiensis or Entrust SC may be applied to control insects on organically grown plants; appropriate chemical treatment may be required for control in commercial. plantations.
Early instar beet armyworm (Spodoptera exigua) feeding under leaf surface
Beet armyworm, Spodoptera exigua, on a cotton leaf
Beet armyworm larave
Beet armyworm damage
Beet armyworm feeding on square
Early instar beet army worm damage
Several early instar beet armyworm larvae feeding in the under side of a cotton leaf.
Braconid wasp parasitizing beet armyworm larva
Beet armyworm larvae
Larva(e) feeding on square
A biological control agent, nuclear polyhedrosis virus, killed the beet armyworm at top.
Beet armyworm (Spodoptera exigua) adult moth
Beet armyworm egg mass
Beet armyworm feeding on cotton
Larva(e) damage to foliage
Holes in bracts associated with bolls; heavy feeding by young larvae leads to skeletonized leaves; shallow, dry wounds on fruit; egg clusters of 50-150 eggs may be present on the leaves; egg clusters are covered in a whitish scale which gives the cluster a cottony or fuzzy appearance; young larvae are pale green to yellow in color while older larvae are generally darker green with a dark and light line running along the side of their body and a pink or yellow underside.
Insect can go through 3–5 generations a year.
Organic methods of controlling armyworms include biological control by natural enemies which parasitize the larvae and the application of Bacillus thuringiensis; there are chemicals available for commercial control but many that are available for the home garden do not provide adequate control of the larvae.
While harvesting is one of the final steps in the production of cotton crops, it is one of the most important. The crop must be harvested before weather can damage or completely ruin its quality and reduce yield. Cotton is machine harvested in the U.S., beginning in July in south Texas and in October in more northern areas of the Belt.
Stripper harvesters, used chiefly in Texas and Oklahoma, have rollers or mechanical brushes that remove the entire boll from the plant. In the rest of the Belt, spindle pickers are used. These cotton pickers pull the cotton from the open bolls using revolving barbed spindles that entwine the fiber and release it after it has separated from the boll.
Once harvested, seed cotton must be removed from the harvester and stored before it is delivered to the gin. Seed cotton is removed from the harvester and placed in modules, relatively compact units of seed cotton. A cotton module, shaped like a giant bread loaf, can weigh up to 25,000 pounds.
Cotton Exports by Country
Cotton texture conceptual
Global sales from cotton exports by country amounted to US$51.2 billion in 2016.
Overall, the value of cotton exports were down by an average -24.5% for all exporting countries since 2012 when cotton shipments were valued at $67.8 billion. Year over year, cotton shipments fell in value by -9.2% from 2015 to 2016.
The two-digit Harmonized Tariff System code for cotton is 52. This broad classification category includes raw cotton, cotton yarn, thread and woven fabrics.
Top Cotton Exports by Country
Below are the 15 countries that exported the highest dollar value worth of cotton during 2016:
China: US$15 billion (29.3% of total cotton exports)
India: $6.3 billion (12.2%)
United States: $5.7 billion (11.1%)
Pakistan: $2.6 billion (5%)
Vietnam: $2.1 billion (4.1%)
Hong Kong: $1.9 billion (3.7%)
Turkey: $1.7 billion (3.4%)
Italy: $1.4 billion (2.8%)
Brazil: $1.4 billion (2.7%)
Australia: $1.2 billion (2.3%)
Germany: $956.6 million (1.9%)
Indonesia: $782.1 million (1.5%)
Spain: $735.1 million (1.4%)
Uzbekistan: $719.3 million (1.4%)
South Korea: $532.5 million (1%)
The listed 15 nations shipped 83.9% of all cotton exports in 2016.
Three of the above countries grew the value of their cotton exports since 2012: Vietnam (up 154.8%), Indonesia (up 10.1%) and China (up 1.1%).
The remaining 12 countries posted declines in their exported cotton sales led by: Australia (down -56.1%), Pakistan (down -51%), Uzbekistan (down -50.3%), Hong Kong (down -46.3%) and Brazil (down -39%).