Environmental Factors Impacting Cotton Fiber Quality

Cotton quality is the foundation of the cotton production industry, impacting the bottom line for both growers and manufacturers. High quality cotton always has a market and often demands a premium price above standard grade. Low quality cotton is difficult to process, can receive deductions in price, and may not be marketable. Environmental conditions during the growing season play a large role in determining fiber quality at harvest.¹ Understanding how fiber quality is impacted can help determine management strategies for high quality cotton production.

Table 1. Sources of fiber quality outcomes and variation.

Water

The amount of water a cotton crop has access to is one of the most important factors that influence fiber quality. If a water deficit occurs prior to flowering, the impact on fiber quality is minimal to none. However, if water stress occurs shortly after flowering through peak bloom, then fiber length can be significantly decreased and micronaire increased.^2,3 Too much water is conducive to disease and can also result in lower fiber quality.

Generally, a cotton crop has a higher drought tolerance than other row crops. Cotton plants can compensate for low moisture levels near the soil surface by growing roots deeper into the soil profile where moisture may be available. Water uptake increases with root growth until soil temperatures of around 95 °F, where uptake begins to decrease. Dryland fields tend to have plants with longer root lengths, as they are not reliant on surface-applied irrigation. However, the ability of a cotton plant to compensate for low moisture conditions decreases as the plant ages.⁴

Proper irrigation management, if possible, can help prevent water stressed plants. Application of plant growth regulators prior to water stress can help limit water loss later. Avoid applying a PGR when the crop is stressed as this can intensify the stress.

Temperature

Heat stress not only reduces yield potential by affecting pollination, plant growth, and development, but also causes damage to cotton fiber. Fiber quality is lowered when daytime temperatures exceed 95 °F and nighttime temperatures exceed 77 °F. High temperatures can compromise fiber quality, impacting many key characteristics:^5,6

• Length: Heat stress can shorten fiber length, limiting its use in certain textile applications.
• Strength: High temperatures during cell wall thickening can make fibers more prone to breakage.
• Uniformity: Heat stress can cause inconsistencies in fiber length.
• Micronaire: Maturity of the fibers can vary, leading to inconsistent micronaire values.
• Lint Percent: Heat stress can lower lint percentage.
• Maturity: High temperatures can interrupt fiber maturation, which can affect the ability of fibers to uptake dye.

High heat disrupts the production of cellulose, the main component of cotton fiber. Optimal cellulose production occurs between temperatures of 77 and 86 °F. High temperatures reduce the plant’s ability to produce sucrose, a dual purpose substance: it is the building block for cellulose and contributes to fiber elongation. When heat stress is combined with drought stress, as it often is, the potential damage to the crop is compounded. Drought-stressed plants close their stomata to conserve water, which results in a higher canopy temperature and lower CO2 intake, limiting photosynthesis. Effectively, heat stress reduces both the quantity and quality of cotton fiber, and with increasing average temperatures, understanding potential management options is essential.⁶

Planting early or selecting early maturing cotton varieties may help reduce the potential for heat stress; however, weather can be unpredictable. Adjusting row spacing can help manage inputs, especially in dryland fields or where irrigation is unable to meet crop demand. Adequate and timely irrigation reduces stress from heat and drought conditions. Plant growth regulator applications can help control excessive vegetative growth and contribute to fiber development. Nutrient uptake, movement, and use can be hindered under high heat conditions. Foliar applications of potassium, zinc, and boron prior to heat stress can help preserve water content in the plant and increase boll production and fiber quality.⁶

High temperatures are not just a fiber quality problem. Historical data indicates heat stress in the Southwestern US has lowered cotton yield potential by 26% and yield potential is projected to continue to decline in the future if average temperatures climb higher.⁶

Light

Sunlight is required for adequate photosynthesis and fiber development in cotton. Limited light conditions that occur in cloudy or shaded areas can significantly reduce photosynthesis. This lowers the concentration of carbohydrates in leaves and bolls and leads to square and boll drop, reducing yield and fiber quality.⁷

Fertility

Adequate fertility is critical for proper fiber development. Nutrient deficiencies can impact fiber strength, fiber length, micronaire, and maturity. This can lead to fibers that break easily and absorb dye poorly. Potassium is particularly important for maximizing fiber quality and can also contribute to yield through photosynthesis, water storage, and root growth.⁸

Soil test results should be followed with recommended fertility applications as nutrient availability is one of the largest factors in determining fiber quality. Be cautious of soils with high salinity, as they can inhibit root growth and nutrient and water absorption from the soil. It is also important to make any necessary pH adjustments to ensure nutrient availability to the crop.

Weather Events

There have been several recent weather events that have greatly impacted cotton crops. The impact of these events can be minimal to complete losses. Managing a crop prior to and after a weather event can be critical for a successful season. Periods of drought can lower fiber length and strength and lead to premature boll opening. Wind and hail result in boll shed and fibers contaminated with debris. Humidity and heavy rain can increase disease pressure and boll rot, lowering overall fiber quality. Poor weather conditions in the final weeks before harvest can lead to a poor color grade. Cotton that is left in the field to weather through multiple rain showers—either in the boll or in a module—can darken, leading to lower grade and value.¹ Fields in the path of a hurricane can be impacted the most. See the article, Managing Cotton Through a Hurricane, for more information.

The growing season can present several challenges to a cotton grower for producing premium cotton lint. From managing temperature and moisture fluctuations to extreme weather events like a hurricane, each event plays into the characteristics of the harvested fiber. Effective management through variety selection, irrigation and nutrient management, and timely PGR applications can help mitigate plant stress and maintain cotton fiber quality.

Related Articles

Maximizing Cotton Fiber Quality

Cotton Fertility

Irrigation Scheduling for Cotton

Sources

¹Brown, S. and Sandlin, T. 2022. How to think about fiber quality in cotton. Alabama Extension. ANR-2637. https://www.aces.edu/blog/topics/crop-production/how-to-think-about-fiber-quality-in-cotton/.

²Loka, D.A., Oosterhuis, D.M., and Ritchie, G.L. 2011. Water-deficit stress in cotton. In D.M. Oosterhuis and W.C. Robertson, Eds. Stress physiology in cotton. The Cotton Foundation. https://www.cotton.org/foundation/stressphyscontents.cfm

³Water-sensitivity of cotton growth stages. Cotton Incorporated, Irrigation Management. https://www.cottoninc.com/cotton-production/ag-resources/irrigation-management/water-sensitivity-of-cotton-growth-stages/

⁴McMichael, B.L. Oosterhuis, D.M., and Zak, J.C. 2011. Stress response in cotton root systems. In D.M. Oosterhuis and W.C. Robertson, Eds. Stress physiology in cotton. The Cotton Foundation. https://www.cotton.org/foundation/stressphyscontents.cfm

⁵Beegum, S. Reddy, K.R., Ambinakudige, S., and Reddy, V. 2014. Planting for perfection: How to maximize cotton fiber quality with the right planting dates in the face of climate change. Field Crops Research. 315: 109483. https://doi.org/10.1016/j.fcr.2024.109483

⁶Saini, D.K., Impa, S.M., McCallister, D., Patil, G.B., Abidi, N., Ritchie, G., Jaconis, S.Y., and Jagadish, K.S.V. 2023. High day and night temperatures impact on cotton yield and quality—current status and future research direction. Journal of Cotton Research. https://doi.org/10.1186/s42397-023-00154-x

⁷Wells, R. 2011. Light and the cotton plant. In D.M. Oosterhuis and W.C. Robertson, Eds. Stress physiology in cotton. The Cotton Foundation. https://www.cotton.org/foundation/stressphyscontents.cfm

⁸Hussain, S., Ali, H., and Gardezi, S.T.R. 2021. Soil applied potassium improves productivity and fiber quality of cotton cultivars grown on potassium deficient soils. PLoS ONE. 16(4): e0250713. https://doi.org/10.1371/journal.pone.0250713

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