A two-year, commercial cotton gin sampling project was conducted during the 2005-06 and 2006-07 ginning seasons to assess the changes in upland cotton quality during the ginning process and throughout the ginning season across the entire cotton belt. This report summarizes the cotton quality information collected to establish a baseline for cotton quality before and after saw-type lint cleaning for future research efforts to address cotton short-fiber content and fiber entanglements (neps) that occur during processing. Fiber quality measurements of ginned lint sampled before and after saw-type lint cleaning followed expected trends in that lint cleaning improved color grades, reduced foreign matter content, reduced fiber length and length uniformity, and increased short-fiber content and neps. Fiber quality measurements before and after lint cleaning summarized by cotton growing region showed similar trends to those summarized across the cotton belt. Differences in fiber quality measurements among regions were presented but not compared as many could likely be attributed to cultivar and environmental differences among sampling sites. As part of a broader effort, this report should aid in developing innovative approaches to clean and maintain the quality of cotton fiber, while reducing short-fiber content and neps.

For research purposes, it is often necessary to gin small cotton samples on laboratory-scale gin stands (lab gins) to evaluate fiber properties, but because lab gins differ from commercial gin plants, the validity of the results obtained has been questioned. The objective of this research was to compare fiber properties between cotton processed with lab gins and commercial gin stands. Seed cotton was collected at the gin stand feeder apron and lint was collected before and after lint cleaning at seven commercial cotton gin facilities. Each seed-cotton sample was subdivided for processing with four lab gins including two from Dennis Manufacturing, one from Continental Eagle Corporation, and one from Custom Fabricators and Repairs (CFR). Fiber properties of all lint samples were measured with the Advanced Fiber Information System (AFIS). Averaged over all commercial gin facilities, the CFR lab gin was found to cause more fiber breakage than the commercial gin stand resulting in a small reduction in fiber length and increase in short fiber content, but no differences were found for the other lab gins. Fineness data for the New Dennis lab gin was lower than the commercial gin stand. Immature fiber content was lower and maturity ratio higher than the commercial gin stand for the Old Dennis, CFR, and Continental lab gins. Neps were higher for the Old Dennis lab gin than the commercial gin stand, whereas seed-coat neps were higher for the CFR lab gin and lower for the New Dennis and Old Dennis lab gin. When these results were analyzed for all commercial gin facilities it was found that in most cases (except neps) differences between the lab gins and the commercial gin stands were not consistent from one gin facility to the next. This proved that results obtained from lab gins cannot be precisely reproduced, even with a correction factor, in commercial gin plants. Correlation analysis indicated that the New Dennis gin stand produced lint samples that were the most similar to commercial gin stand lint samples when considering all properties, and most correlations were strong for other lab gins as well. These results show that lab gins offer an effective, convenient screening tool for cotton researchers predicting fiber quality in commercial gins.

One goal of lint cleaning at a cotton gin is to reduce the non-lint material to an acceptable level with minimal fiber damage. In an effort to improve lint cleaner performance, an initial study was conducted on lint collected before and after lint cleaning at nine commercial gins across the cotton belt to characterize non-lint content. Samples front this study were first processed with an MDTA-3 (Micro Dust and Trash Analyzer 3, SDL Atlas, Stockport, U.K.) to determine trash, fiber fragment, and dust content. The trash portion was retained for additional manual fractionation to determine the percent of material classified as seed coat fragments (SCF), motes, funiculi, sticks, leaf, bark, lint, and "other" material. Leaf, SCF, and sticks were the largest fractions, accounting for 81% of the total trash sample. Overall, total trash decreased by 57% due to lint cleaning, and trash fractions remained consistent in samples before and after lint cleaning. Lint cleaning efficiency in terms of SCF was less than the overall cleaning efficiency, and lint cleaning efficiency for bark, mote, and other (all minor components) was higher than the overall cleaning efficiency. The lint cleaning efficiency for SCF was increased significantly when higher SCF levels were found before the lint cleaner, but this trend was not found for other fractions. Results of this experiment will help direct future studies to improve lint cleaning.

One goal of lint cleaning at a cotton gin is to reduce the non-lint material to an acceptable level with minimal fiber damage. In an effort to improve lint cleaner performance, an initial study was conducted on lint collected before and after lint cleaning from 9 commercial gins across the cotton belt to characterize non-lint content. Samples from this study were first processed with a MDTA-3 (Micro Dust and Trash Analyzer 3, SDL Atlas, Stockport, England) to separate lint, trash, fiber fragments, and dust to determine the fractional composition of the original sample. The trash portion was retained for additional manual fractionation to determine the percent of material classified as seed coat fragments (SCF), motes, funiculi, sticks, leaf, bark, lint, and other material. Leaf, SCF, and sticks were the largest fractions accounting for 81% of the total trash sample. Overall, total trash decreased by 57% due to lint cleaning, and trash fractions remained consistent in samples before and after lint cleaning. Lint cleaning efficiency in terms of SCF was less than the overall cleaning efficiency, and lint cleaning efficiency for bark, mote, and other (all minor components) was higher than the overall cleaning efficiency. The lint cleaning efficiency for SCF was increased significantly when higher SCF levels were found before the lint cleaner, but this trend was not found for other fractions. Results of this experiment will help direct future studies to improve lint cleaning.

A two year, belt-wide commercial cotton gin sampling project was initiated in 2005 for the 2005-06 and 2006-07 ginning seasons to assess the changes in upland cotton quality throughout the ginning process and the ginning season with the ultimate goal of identifying areas where improvements can be made in preservation of fiber quality. This report discusses analysis of the first year data. Overall fiber properties after one stage of lint cleaning were typical of U.S. cotton. In order to compare quality of fiber in seed-cotton samples with ginned lint samples from a commercial gin, hand ginning to lab ginning relationships were developed and used to correct the fiber quality data for lab ginned seed-cotton samples to near pre-ginning values. Trash content analyses showed that cleaning machines typically reduced foreign matter content per lint basis from as high as 50% at the module to about 4% at the lint slide. Short fiber content (SFC) values after ginning were double those at the feeder and increased at a lesser rate with lint cleaning. Nep counts were nearly tripled by the gin stand, then increased steadily as the lint passed through the first and second stage of lint cleaning, but the increases associated with the lint cleaners was much less than that at the gin stand. Length measurements also decreased due to processing. More in-depth data analyses will continue after the 2nd year data are complete. This future work will focus on within-ginning process changes, changes as the ginning season progressed, interactions among fiber properties (i.e. SFC and micronaire or neps and length), and effects of cleaning.