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Production Technology of Cotton
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How to Grow Cotton
English name: Cotton.
Family: Malvaceae.
Species
1. The American cotton:
a) Gossypium hirsutum (Middle America or Mexico).
b) Gossypium herbaceum (Africa).
2. Deshi cotton:
a) Gossypium arboreum (South east Asia).
b) Gossypium barbadense (Egypt).
Origin: Pakistan.
Distribution
Cotton is one of the most important cash crops cultivated in about 60 countries in the world. Russia, USA, Mexico, Sudan, Egypt, China, Pakistan, India, Indonesia, Turkey, Brazil etc account for about 85 % of the total cotton production.
Importance
Cotton is one of the important cash crops in Bangladesh. It is the main raw materials of textile industry. Raw cotton is also used for medical and surgical purposes.The linters are used as filling materials for making cushions.
Variety
DEF 1, D 4, D 10, D 124, Deltafine 1, Rupali, Ava, Rangunia, Chakoria etc. Main varieties of American cotton grown in Bangladesh are CB1 (Deltapine90), CB3 (Deltapine50), CB5 (a cross between Deltapine and indigenous variety), CB9 (Developed from SI/91/646) and CB10 (developed from BC0397).
Climate
• Cotton is a crop of subtropical climate.
• Cotton needs on an average a minimum temperature of 60 F for germination.
• 70-80 F for vegetative growth.
• 80-90 F with cool nights during fruiting period.
• 70-80 cm rainfall is enough for cotton cultivation.
• An annual rainfall of at least 50 cm is minimum requirement for cotton unless it is grown on irrigated soils.
Ultimately rains and the heavy humid weather during later stages of cotton season may spoil the produce, lower its ginning properties or promote attack of insect, pest, diseases. So weather should be clear at harvesting because rain at this stage will discolour the lint and reduce its quality.
Soil
Cotton needs any type of soil but with a excellent water holding capacity and aeration and good drainage as it cannot withstand excessive moisture and water logging. The major group of soil for cotton cultivation are the alluvial soils, loam, black soils, red sand loam. pH 5-8.5 is the best for cotton cultivation. Alkaline and saline soil is not good for cotton cultivation.
Land preparation
For cotton cultivation deep ploughing is essential because cotton is a deep rooted crops. The soil should be loose and friable. 3-4 ploughing followed by cross ploughing and laddering are essential to bring the soil to a good tilt for cotton cultivation.The land should be well leveled and weed free.
Seed rate
Depending upon the variety, soil type, the cultivation on practices and method of sowing, seed rates and spacing have been recommended.
• Bangladesh: Average 15 kg/ha.
• Indian cotton: 12-15 kg/ha.
• American cotton: 15-20 kg/ha.
Spacing
• Indian cotton: 45-50 cm X 50-60 cm.
• American cotton: 50-60 cm X 60-90 cm.
Depth of sowing: 4-5 cm.
Time of sowing
• Kharif: April – May / May – June (Never later than 15 July).
• Rabi: August – September / Late September – October.
Seed treatment
The seed of most of the cotton varieties, particularly the American type is covered by short fibre called fuzz. The fuzz cling with seed together. Thus creating a problem in free rolling and separation of individual seed for sowing.
Nonchemical: In this case the seeds are soaked in water for 10-12 hours and then they are rubbed with fresh cowdung, wood ash or soil dust. After rubbing the seed is spread in the shade for few hours. When they are dried they can be used for sowing.
Chemical: The seeds are soaked in strong commercial Sulphuric acid (H2SO4) for 2 minutes. Then the seeds taken out washed in running water to remove the chemical. The seeds are also immersed in the solution of ZnCl2 for 10-12 minutes and then washed. This chemical dissolve the fuzz (disturbing materials). Seeds are treated only for removing fuzz but also for removal of boll worm, different pests and enhance germination.
Fertilizer Application
Fertilizer Quantity (ha)
Organic matter 5-8 ton
Urea 112-148 kg
TSP 100 kg
MoP 100-132 kg
Sulphur 19-24 kg
Zinc 4-6 kg
Intercultural operation
Weeding: Weed reduce crop yield seriously. In rabi season 3-4 and in kharif season 2-3 weeding and thinning is necessary. Hoeing the crop more frequently. Some weedicide such as TOKE25, Ansar521, Basalin 46 EC be applied for controlling weed. The critical period for weed competition in cotton ranges from sowing to 60 DAE. So cotton field should be kept weed free at least up to 60 DAE.
Thinning: It is done twice , firstly within 10 DAE keeping two seedling per hill and secondly within 20 DAE keeping single seedling per hill.
Gap filling stage: Gap filling should be done by resowing.
Topping: It is desirable to remove the top growing point (topping) once from each plant at a height of 11.2 m or between 80-90 days of crop growth. The practice further terminal growth encourage sympodial branching of boll development. It also facilitates spraying operations and picking of cotton.
Irrigation and drainage
Flowering and boll formation are the critical stages from the point of irrigation. Inadequate irrigation stages during this stages leads to a heavy shedding of flower buds and bolls. In rabi season (in case of abnormal drought condition) 23 irrigation is needed. First at 40 DAS (before blooming) and Second at 55 DAS (after flowering). In kharif season, no need to irrigation.
Cotton during its early stage of growth is very sensitive to water stagnation for long period. Therefore, drain away excess water of rain or irrigation. The crop cannot tolerate water logging condition at any stage of growth.
Diseases and pests
Major insect of cotton are Pink boll worm, spotted boll worm, cotton leaf roller, aphid etc.
• Cotton aphids are controlled by spraying Malathion 0.08 %.
• Cotton leaf roller, spotted boll corn, pink boll corn are controlled by dusting crop with 10 % carbonyl.
• Red cotton bug and dusky cotton bug are controlled by dusting 5 % B.H.C.
Important disease of cotton are Wilt, Anthracnose, Leaf blight, boll rot etc.
• Seed should be treated with AGROSANGN/ GRANOSANM.
• Spray the crop with Cupper fungicide.
Harvesting
Cotton is an important crop. It is harvested by picking fully opened boll by hand in 3-4 pickings at 25-30 days interval. Picking is done when bolls burst fully. Bolls start bursting after 110-120 days of sowing. The season of harvesting varies with of sowing, duration of variety. Well dried bolls are picked.
Maturity symptoms
• Picking should be done when boll begin to fully burst.
• Boll setting on the stem are in an angle of 450 with stem.
• The growth and development of the plant is stopped.
• The plant become yellow.
• Flower turn to purple color.
Picking time
• Rabi season: February – March / March – April.
• Kharif season: October – December.
GOT (Ginning Out Turn)
Ginning is a process of delinting the commercially used lint from seed. Seed cotton composed of 2/3 seed and 1/3 lint. This ratio (2:1) is known as GOT. Yield increased with the increased of GOT.
Post harvest operation
To maintain the quality of fiber for textile industry and good quality seed for oil extraction , care should be taken to handle the picked cotton. Kapas picked from open bolls should not be contaminated with dried leaves and other foreign matter.
Yield
• Rabi season: 1000-1500 kg/ha.
• Kharif season: 800-1000 kg/ha.
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