Cultivation of Cotton

Cotton (Gossypium species) is one of the most important fiber crops grown globally, providing raw material for the textile industry. It is also a significant oilseed crop and plays a crucial role in the economy of many countries.

Scientific Classification

• Family: Malvaceae
• Genus: Gossypium
• Species: There are four main species of cotton:
  • Gossypium hirsutum (upland cotton)
  • Gossypium barbadense (extra-long staple cotton)
  • Gossypium herbaceum (old world cotton)
  • Gossypium arboreum (tree cotton)

Origin and History

• Native Region: Cotton is believed to have been domesticated in India, China, and parts of Africa over 5,000 years ago.
• Introduction to Other Regions: It spread to the Americas and other parts of the world, with major cultivation in countries like the United States, India, China, and Brazil.

Production

Global Cotton Production

• Total Area:7 million hectares
• Global Production:3 million tons
• Average Yield:2 tons per hectare

Cotton Production in India

• Total Area:8 million hectares
• Total Production:53 million tons
• Average Yield:13 tons per hectare

Major Cotton-Producing Countries:

• • China: Largest producer of cotton.
  • India: Second-largest producer and a major exporter.
  • United States: One of the largest producers and exporters.
  • Pakistan: Significant producer, especially in the textile industry.
  • Brazil: Major exporter of cotton.
• Global Area: Approximately 33 million hectares are under cotton cultivation globally, with production figures exceeding 25 million metric tons.

Cotton Distribution in India:

• Hybrid Cotton: 40%
• Gossypium arborium: 36%
• Gossypium herbaceum: 16%
• Gossypium hirsutum: 8%
• Gossypium barbadense: 0.2%

Classification of Cotton

• Cotton has 20 species, but only 4 are cultivated commercially:
  • Deshi / Asiatic Cotton (Diploid species, 2n = 26) Gossypium arborium, Gossypium herbaceum
  • American Cotton / Egyptian Cotton (Tetraploid species, 2n = 52) Gossypium hirsutum, Gossypium barbadense

Agronomic Features

• Plant Type: Cotton is a dicotyledonous plant, typically growing as an annual in the field.
• Height: Cotton plants grow from 0.5 m to 2 meters in height.
• Root System: It has a taproot system, which helps it access deeper soil moisture.
• Leaves: The leaves are broad and palmately lobed.
• Flowers: Cotton flowers are typically white or yellow and turn pinkish-red before fading to a red-brown color.
• Cotton Bolls: The cotton fibers are produced within the bolls that develop after flowering. Each boll contains cotton fibers and seeds.

Importance of Cotton

• Primary Use: Cotton is grown primarily for its fiber, which is used in the textile industry for making clothes, home textiles, and other products.
• Secondary Uses:
  • Cottonseed is used to produce oil for cooking and industrial purposes.
  • Cottonseed meal is used as animal feed.
  • Cotton stalks are used for making paper and as biofuel.
• Economic Importance: Cotton is a vital cash crop for many countries and provides employment to millions of people in agriculture and related industries.

Climate and Soil Requirements

• Climate: Cotton requires a warm climate to grow, with an optimum temperature range of 20°C to 30°C during the growing season. It is sensitive to frost and requires a long frost-free period.
• Rainfall: Cotton grows well in areas with 400-1000 mm of annual rainfall. Excessive rainfall can damage the crop, especially during the flowering and boll formation stages.
• Soil Type: Cotton prefers well-drained, sandy loam soils rich in organic matter. The ideal soil pH for cotton cultivation is 6.0-7.5.
• Water: Cotton requires moderate irrigation if rainfall is insufficient. The critical periods for water requirement are flowering, boll formation, and boll development.

Field Preparation

• Land Preparation:
  • Plowing: Fields are plowed to a depth of 15-20 cm to loosen the soil.
  • Fertilization: Incorporation of organic manure and the application of appropriate NPK fertilizers (nitrogen, phosphorus, and potassium) is essential for good growth and yield.
  • Seed Bed: Cotton requires a fine seedbed for optimum seed germination.
• Pest and Weed Management: Cotton is prone to pest infestations, especially bollworm and aphids, and needs regular pest management through cultural, biological, and chemical controls.

Cotton Varieties in India

India grows a range of cotton varieties, each suited to different climates and soils. Here are some key varieties based on the species:

• Upland Cotton (Gossypium hirsutum)These varieties are most widely cultivated in India due to their high yield and adaptability. Some prominent varieties include: Suvernarekha, Bikaneri Nerma, LRA 5166, NCS 145, Bunny, Shanker 6
• Egyptian Cotton (Gossypium barbadense) Known for its long and fine fiber quality, these varieties are grown in select areas, mostly in semi-arid regions. Giza 45, Suvin
• Indian Cotton (Gossypium herbaceum) Mainly grown in the semi-arid regions of India, these varieties are more drought-tolerant. Nellore, Surat, Nagpur
• Tree Cotton (Gossypium arboreum) This species is suitable for tropical climates and is mostly grown in specific areas of India. Coimbatore, Vijayanagaram
• Bt Cotton Varieties (Genetically Modified) Bt cotton varieties are genetically modified to resist bollworm, one of the most destructive pests in cotton cultivation. Some well-known Bt cotton varieties in India include: BG II (Bollgard II), RCH 134, MRC 7031, Rashmi, NK 8612

Bt Cotton (Bacillus thuringiensis Cotton)

• Bt. Cotton is a genetically modified cotton that contains a gene from Bacillus thuringiensis (Bt), which makes it resistant to cotton bollworms.
• Cry-1Ac gene was introduced to cotton to produce proteins lethal to bollworm larvae.
• Bt. Cotton Varieties:
  • Bollgard I: Developed using Cry-1Ac gene by Mahyco in collaboration with Monsanto.
  • Bollgard II: Developed in 2006, containing both Cry-1Ac and Cry-II Ab genes.
• GEAC (Genetic Engineering Approval Committee) permits the commercial release of Bt cotton in India under the Ministry of Environment and Forests.
• Benefits:
  • Reduces insecticide applications by more than 50%.
  • The protein produced by Bt. cotton is lethal to the digestive system of bollworm larvae.
• First Generation of Bt Crops: Cotton, Maize, and Potato were approved in 1995 and commercially grown from 1996.

Hybrid Cotton Varieties:

• H-4 (Hybrid-4) Developed by Dr. C.T. Patel of Gujarat Agricultural University, Surat in 1970. First commercial hybrid cotton variety. Cross between G-67 and American Nectorless.
• Varalaxmi First interspecific hybrid between Gossypium hirsutum and Gossypium barbadense. Released by UAS Dharwad (Karnataka).
• Savita, Surya Intraspecific hybrids of Gossypium hirsutum.
• Dhanlaxmi Another hybrid variety.

Time of Sowing

• Sowing Season: In India, cotton is typically grown during the kharif season, with sowing done in April to June. The exact timing depends on the climatic conditions of the region.
• Spacing:
  • In-row spacing: 60-75 cm
  • Between rows spacing: 75-90 cm
  • This helps in providing adequate air circulation and sunlight for healthy growth.

Seed Rate The typical seed rate for cotton is 10-12 kg per hectare depending on the variety, soil type, and climate conditions.

Fertilizer and Nutrient Requirements

• Cotton requires a balanced supply of nutrients to grow well:
  • Nitrogen (N): Essential for leaf and vegetative growth.
  • Phosphorus (P): Vital for root development.
  • Potassium (K): Helps in improving the strength of the plant and boll development.
• Typical fertilizer recommendation: 60-90 kg of N, 20-40 kg of P2O5, and 30-60 kg of K2O per hectare.
• Micronutrients such as zinc and boron are also important for proper growth and cotton boll formation.

Weed Management

• Weed Control: Weeds can significantly reduce cotton yields by competing for nutrients, water, and light.
• Methods:
  • Herbicides: Application of pre-emergence and post-emergence herbicides.
  • Hand weeding: In small-scale farms, hand weeding is also common.
  • Inter-cropping: Growing cotton with other crops to reduce weed competition.

Irrigation

• Cotton requires sufficient water during the flowering and boll development stages. While it is a drought-tolerant crop, irrigation during dry spells enhances yield.
• Methods: Drip irrigation, flood irrigation, and sprinkler systems are commonly used in cotton farming.

Harvesting

• Maturity: Cotton plants take about 5-6 months to reach maturity after sowing. The cotton bolls mature at different times, so harvesting is done in stages.
• Harvesting Time: The ideal time for harvesting is when the bolls open up, and the cotton fibers are fluffy and white.
• Manual Harvesting: In small-scale farming, cotton is manually picked by hand.
• Mechanical Harvesting: In large-scale production, cotton is harvested using mechanical pickers and strippers.

Post-Harvest Management

• Ginning: After harvesting, cotton is taken to cotton gins, where the fiber is separated from the seeds.
• Seed Treatment: Cottonseed can be processed for oil extraction or used for replanting.
• Storage: Cotton bales should be stored in dry, well-ventilated warehouses to avoid moisture damage and pest infestation

Yield

• Average Cotton Yield in India: Around 400-500 kg/ha.
• Top Cotton Producing States:
  • Maharashtra: 800-1,200 kg/ha
  • Andhra Pradesh: 700-1,000 kg/ha
  • Gujarat: 500-800 kg/ha
  • Haryana: 600-800 kg/ha
  • Rajasthan: 500-700 kg/ha

Hybrid Varieties and Bt Cotton: These can yield 1,200-1,500 kg/ha under optimal conditions, significantly higher than traditional varieties.

Uses of Cotton

1. Textile Industry: Cotton is primarily grown for its fiber, which is spun into yarn and woven into fabric. Cotton fabric is used for making clothes, sheets, towels, and other household textiles. It is valued for its comfort, breathability, and softness.
   • Cotton fabrics: Denim, muslin, calico, poplin, terrycloth, and corduroy are some of the many fabric types made from cotton.
2. Cottonseed Oil: Cotton seeds contain oil, which can be extracted and used in food products, cosmetics, and industrial products. Cottonseed oil is commonly used for cooking and frying, as it has a mild flavor and high smoke point.
3. Cottonseed Meal: After oil extraction, the remaining cottonseed meal is used as animal feed. It is a good source of protein for livestock and poultry.
4. Biodegradable Products: Cotton fibers are increasingly being used to create environmentally friendly products, such as biodegradable packaging and eco-friendly wipes.
5. Medical Uses: Cotton is used in the medical field for making cotton swabs, bandages, gauze, and surgical products due to its softness, absorbency, and hygiene.
6. Cotton in Bioplastics: Cotton fibers have been explored as a raw material for bioplastics that can degrade naturally, making them a promising option for sustainable packaging.