Cotton (Gossypium) fiber has been known and highly valued by people throughout the world for more than three thousand years. The early history of cotton is obscure. A vigorous cotton industry was present in India as early as 1500 b.c.e. From India, the cultivation of cotton spread to Egypt and then to Spain and Italy. In the New World, a different species of cotton was being grown in the West Indies and South America long before Europeans arrived. In the United States, cotton is grown from the East Coast to the West Coast in the nineteen southern most states.
Botanically, cotton is in the mallow family, which also includes okra, hollyhock, hibiscus, and althea. Cotton has a taproot and branching stems. Flowers form at the tips of fruiting branches, and the ovary within each flower develops into a boll, which contains the seed, fiber, and fuzz. The fiber, most commonly referred to as lint, develops from epidermal cells in the seed coat of the cottonseed. The fiber reaches its maximum length in twenty to twenty-five days, and an additional twenty-five days are required for the fiber to thicken. Fiber length from 2.0 to 2.4 centimeters is referred to as short-staple cotton, and fiber length from 2.4 to 3.8 centimeters is called long-staple cotton.
The boll normally opens forty-five to sixty-five days after flowering. Cotton is native to tropical regions but has adapted to the humid, subtropical climate, where there are warm days (30 degrees Celsius), relatively warm nights, and a frost-free season of at least 200 to 210 days. There are eight species of cotton in the genus Gossypium, but only three species are of commercial importance. Gossypium hirsutum, also known as upland cotton, has a variable staple length and is produced primarily in North and Central America. Gossypium barbadense, long-staple cotton, is primarily produced in South America and Africa. Gossypium herbaceum is shorter-staple cotton native to India and eastern Asia.
Cotton is one of the more labor-intensive and expensive crops to produce. The most opportune time to plant cotton is at least two weeks after the last killing-frost date of the region. Prior to seeding, the field is prepared by plowing to a depth of 2.5 centimeters. Fertilizer, which is applied before seeding or at the same time the seeds are planted, is placed to the side and below the cotton seed. Once the seeds germinate and emerge from the soil, they often have to be thinned, and shortly afterward the producer begins to apply irrigation water as needed. After the plants have developed a stand, weed control becomes crucial. Weeds are controlled both by cultivation and herbicides.
Cotton plants are subject to invasion by a variety of insect pests, such as the boll worm and boll weevil, therefore considerable attention is given to insect control, typically using a number of different insecticides.
When the bolls ripen with mature fiber, the leaves of the plant are removed by the application of a chemical defoliant, and the fiber is harvested. Harvesting was once done almost entirely by hand, but today mechanical pickers harvest almost all the cotton produced in the United States. The picked cotton is ginned to remove the seed and compressed into bales. The bales are transported to a cotton mill, where the cotton is cleaned and spun into yarn, which is then woven into fabric. One pound of fiber is sufficient to produce up to 6 square yards of fabric.
See also: Flax, Hemp, Minor Crops
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