Submitted to: Agronomy Journal
Publication Type: Popular Publication
Publication Acceptance Date: 8/16/2004
Publication Date: 1/15/2005
Citation: Bednarz, C.W., Shurley, D.W., Anthony, W.S., Nichols, R.L. 2005. Yield, quality and profitability of cotton produced at varying plant densities. Agronomy Journal. 97:235-240 (2005).
Interpretive Summary: Discounts for certain cotton quality properties, especially micronaire, reduce the profitability of producing cotton in the United States. Studies have shown that cotton fiber length and strength are primarily under genetic control while micronaire and fineness are more influenced by the environment. Premature termination of the plant is currently used to control micronaire, however, yield is sacrificed. This study investigated the impact of how closely the cotton plants were planted together on the location of the bolls on the plant, and thus fiber quality. Of the fiber properties investigated, micronaire and fineness were most affected by plant density. Reductions in price were greatest for micronaire. Only small gains in length and strength were made through modifications in plant density. Thus, price discounts for high micronaire cottons can be mitigated through increased seeding rate and plant density. Variety FM 966 consistently outperformed DPL 458 BR at all plant densities, indicating that fiber properties are highly genetically influenced. Thus, to maximize fiber quality, cultivar selection is of greatest importance while management of plant density to maintain or maximize genetic potential is secondary. This finding provides another method to minimize the impact of micronaire on cotton prices.
Technical Abstract: Modified fruit distribution through varying plant density may impact cotton (Gossypium hirsutum L.) fiber quality. This study was conducted to determine how lint yield, fiber quality and profitability of cotton are manipulated through plant density. Two cotton cultivars were over seeded and hand thinned to 3.6, 9.0, 12.6 and 21.5 plants m-2 at two University of Georgia experiment stations in 2001 and 2002. After the studies were machine harvested each year, the seed cotton was shipped to the USDA/Agricultural Research Service/Cotton Ginning Research Unit in Stoneville, MS for ginning. While ginning, six lint samples were collected per plot for fiber quality analyses. Net returns were then determined from yield, quality and cottonseed cost data. Lint yields were greatest at 12.6 plants m-2 with a numerical decrease occurring at 21.5 plants m-2. Of the fiber properties investigated, micronaire and fineness were most affected by plant density. In addition, quality adjustments in price were greatest for micronaire. Thus, avoidance of price discounts for high micronaire fiber may occur through adjustments in seeding rate and plant density. Net returns above seed costs were greatest at 12.6 plants m-2 for both cultivars. One cultivar consistently outperformed the other in fiber quality. Results from this study support the findings of others that fiber properties are highly genetically influenced. Thus, to maximize fiber quality, cultivar selection is of greatest importance while management of plant density to maintain or maximize genetic potential is secondary.