5. Cotton acreage planting declined from 15.27 million acres in 2006 down to 9.41 million acres in 2008.
6. Decrease due largely to higher prices for competing crops like soybeans, corn, and peanuts and less fertilizer expense especially for soybeans and peanuts.
7. Cotton yield is figured in bales. 1 bale is 480-lb net weight.
8. 5 yr. average yield for all U.S. grown cotton is 826 pounds of lint per acre.
11. One of the most economically and socially important crops in the world. Size of the plant depends on: soil, climate, water conditions, plant variety. Grows best in clay loam soil with a semitropical climate. Perennial shrub with tropical origins that is produced in an annual row crop environment in the US. Growing season: 6-7 months. Typically takes about 175 days from planting to harvest. Bt cotton was introduced in 1996. Successful cotton production depends on an integrated and intense management strategy.
15. Cotton seeding requirements Soil temperature: min. 68°F at 2” depth. Planting dates range from April 15th through the end of May. Planting depth 0.5” to 1.5” depending on soil moisture. The optimal plant population: 30,000 to 60,000 plants per acre in 30 to 40 inch rows. Typical row width 36 to 40 inches. Seed is planted using mechanical planters.
26. Seedling Emergence 4-14 days after planting seedling emerges. About a week after seedling establishes, first true leaf forms above cotyledons. Shift from emergence to vegetative growth.
27. Root Development Most of the cotton plant’s carbohydrate energy is directed to root growth prior to the time reproductive growth begins. The cotton root system develops as a taproot system with smaller, lateral roots stemming off of the taproot.
28. Vegetative Growth The development of vegetative growth and fruiting is highly related to temperature if adequate moisture is available. Main stem leaves form first from main stem nodes. Generally, a new node is produced from the apical meristem an average of every 3 days, although nodes develop more quickly early in the growing season than later in the season. Branches grown on cotton plants are divided into two groups, vegetative and fruiting branches. Vegetative branches grow straight and hold the fruiting branches and main stem leaves Fruiting branches grow in a zigzag pattern.
29. Vegetative Growth A fruiting bud, called a square, begins to form at the initiation of the fruiting branch, accompanied by a subtending leaf; typically 4th through the 8th nodes. The subtending leaves provide carbohydrate energy for the squares. The first square produced on a fruiting branch is referred to as a first-position square. As this square develops, the internode between the main stem and the square elongates. An axillary meristem also develops next to this square. The axillary meristem produces a second position square and subtending leaf. Several squares may be produced on a fruiting branch.
30. Vegetative Growth Control Cotton has an indeterminate growth habit and can grow very tall under conditions of unrestrained growth. Unmanaged growth promotes disease and makes cotton crop harvesting very difficult. Growth regulators, such as Mepiquat chloride, are generally applied to cotton to slow internode elongation, especially for well-fertilized irrigated cotton.
31. “Flowering” Squares are visible on nodes 4 - 8 about 35 days after planting. 21 day period from square to bloom. Typically, blooming lasts 6 weeks. Cotton flower is a complete flower; contains both male and female parts. Pollinated flowers form cotton bolls. On the day a flower opens it is white in color. Pollination of that flower usually occurs within a few hours after the white flower opens. On the second day the flower will have a pink-like color, and a red color on the third day. Around 5-7 days after bloom, flower dries and falls off exposing boll.
32. Boll Development After pollination, it takes 50 days for the boll to fully develop and “open.” Three phases of boll development Enlargement Filling Maturation
33. Boll Development – Enlargement The enlargement phase of boll development lasts approximately 3 weeks. Each fiber develops from a single epidermal cell on the seed coat. During this time the fibers produced on the seed are elongating and the maximum volume of the boll and seeds is attained. The fiber at this time is basically a thin walled tubular structure, similar to a straw. During the enlargement phase, the development of the fiber is very sensitive to adverse environmental conditions. Low water availability, extremes in temperature and nutrient deficiencies (especially potassium) can reduce the final fiber length.
34. Boll Development – Filling The filling phase of boll development begins during the fourth week after flowering. Fiber elongation ceases and secondary wall formation of the fiber begins. This process is also known as fiber filling, or deposition. Cellulose is deposited inside the elongated fiber every 24 hours, filling the void space of the elongated fiber. The deposition of cellulose into the fiber cell is also sensitive to environmental conditions. Water, temperature and nutrients (especially potassium) are the primary environmental factors that influence this stage of boll development. The filling phase of boll development continues into the sixth week after pollination.
35. Boll Development – Maturation The boll maturation phase begins as the boll reaches its full size and maximum weight. During this phase, fiber and seed maturation take place and boll dehiscence (spontaneous opening) occurs. The capsule walls of the boll dry and shrink. This shrinking causes the suture between the walls to split, and the boll opens.
39. Harvesting Practices Harvesting is the most important phase of cotton crop production. 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 Cotton Belt. In the U. S., cotton is chemically defoliated or desiccated prior to harvest. Defoliants are used on the taller varieties of cotton that are machine picked for lint and seed cotton, Desiccants usually are used on short, storm-proof cotton varieties of lower yield that are harvested by mechanical stripper equipment. More than 99 percent of the national cotton area is harvested mechanically. Two principal harvest methods: machine picking and machine stripping. Picking is practiced throughout the cotton regions of the U. S. Stripping is limited chiefly to the dry plains of Texas and Oklahoma.
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41. Uses devices such as belted fingers, interlocking lugs, fingers or combs, steel rolls or brushes to remove burr and all from the plant.
42. Designed to pick open bolls by means of spindles, fingers or prongs without material damage to foliage or unopened bolls.
43. Usually is used more than once since cotton is a continuous fruiting plant during the growing season.
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45. Harvesting Process Prior to harvest, cotton crop is chemically treated to ease harvesting process. Cotton is mechanically harvested. With a stripper, the ripe boll is separated from the burr, unopened bolls, and branches. Raw cotton moves to storage hopper, crop residue is deposited on ground through chutes. With a picker, the raw cotton moves to a storage hopper. Raw cotton is placed into modules and packed into bales. Bales are transported to gins for processing. Ginning is the process of separating the cotton lint from the seed.
Hinweis der Redaktion
PIX (Mepiquat chloride) is a systemic plant growth regulator, extensively used in cotton production for the last two decades. PIX treated cotton plants tended to be shorter and narrower with thick and smaller leaves. PIX has been known to reduce the synthesis of gibberellic acid, resulting in the suppressionof cell enlargement. Well managed cotton in terms of providing good irrigation and fertilizers sometimes result in extensive vegetative growth. Cottonplants that are highly vegetative are subject to more disease and harvest losses, resulting in lower yields.
Defoliate - To cause the leaves of (a plant, tree, or forest) to fall off, especially by the use of chemicals.Desiccate – to dry out
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