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Title: Comparison of Five Small-Scale Laboratory Gins to Seven Commercial Gins Sampled Across the Cotton Belt

item Boykin Jr, James
item Whitelock, Derek
item Buser, Michael
item Armijo, Carlos
item Holt, Gregory
item Valco, Thomas

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 12/20/2007
Publication Date: 7/1/2008
Citation: Boykin Jr, J.C., Whitelock, D.P., Buser, M.D., Armijo, C.B., Holt, G.A., Valco, T.D., Findley, D.S., Barnes, E.M., Watson, M.D. 2008. Comparison of Five Small-Scale Laboratory Gins to Seven Commercial Gins Sampled Across the Cotton Belt. National Cotton Council Beltwide Cotton Conference. Nashville, TN. CD ROM pp 737-752.

Interpretive Summary: In 2006, there were 24 million bales of cotton harvested in the U.S. of which some 19.5 million were expected to be exported. The quality of the cotton fibers is important to both domestic and foreign consumers, but foreign consumers typically demand higher fiber quality. Cotton production research focuses primarily on yield, but fiber quality is also a concern. To measure the quality of cotton lint, it must first be removed (ginned) from the seed. In commercial processing in the USA, cotton is mechanically harvested and processed with typical ginning machinery sequence that is known to alter fiber properties. Samples of the final product is measured to determine its quality based on fiber properties such as color, length, strength, fineness, maturity, trash content, and nep content. Small laboratory gin stands are a useful tool in cotton research involving small plots of cotton. Fiber can be removed from small quantities of seed cotton in order to assess the fiber quality. Utilizing these small gin stands before determining fiber properties is different from commercial ginning in several ways, so the validity of this method has been questioned. In this study, five of these laboratory gin stands were compared to commercial gins based on fiber properties of the lint determined with the Advanced Fiber Information System. Results indicated that most properties were not consistent between laboratory gins. Differences were not solely related to mechanical differences in gins, but were most likely influenced by environmental conditions which were not controlled in the commercial gin. The conclusion drawn from the results was that these gins are a useful tool in cotton research, as indicated by previous research, but it is important to control as many other factors as possible and know the limitations of conclusions drawn from experiments utilizing these laboratory gins.

Technical Abstract: In research, cotton lint ginned from small seed cotton samples with laboratory scale gin stands is analyzed to estimate properties of lint after commercial ginning, but these gin stands differ from commercial gins. The objective of this experiment was to compare the fiber properties of lint from several commercial gins to the fiber properties of lint from several laboratory gin stands. Seed cotton and lint sampled simultaneously at the gin stand feeder apron, after the gin stand, and after lint cleaning were collected from seven commercial gins; and the seed cotton samples were ginned with five laboratory gin stands and by hand. The fiber properties were measured with the Advanced Fiber Information System (AFIS). All AFIS properties differed significantly with the factors gin (including the seven commercial gins) and machine (including lint removed with five laboratory gin stands, lint sampled after the commercial gin stand, lint sampled after the commercial lint cleaner, and hand ginned lint), and there were significant interactions between the factors gin and machine. The interaction indicated that differences among commercial gins were not predicted consistently with all machines, and further analysis revealed that lint samples from none of the laboratory gin stands could be used to predict all fiber property differences among commercial gins. In many instances, small laboratory gins (which were operated in a climate controlled environment) produced samples that were more similar among themselves than when compared to samples obtained after the commercial gin stand, so differences may have been related to the environmental conditions in the commercial gins. It was also likely that differences in machine design, both in laboratory and commercial gin stands, contributed to differences in fiber properties. In conclusion, laboratory gin stands will not consistently predict fiber properties of different commercial gins in different environments, but this does not mean these machines are not useful in other applications such as ginning small research plots for fiber quality analysis.