|Boykin Jr, James|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 6, 2008
Publication Date: April 15, 2008
Citation: Boykin Jr, J.C. 2008. Tracking Seed Coat Fragments in Cotton Ginning. Transactions of the ASABE. Vol. 51(2): 365-377. Interpretive Summary: Approximately 20 million bales of cotton are produced in the U.S. annually with about 75% exported. It is important that this cotton is processed efficiently while maintaining the quality demanded by domestic and foreign consumers. One issue that is becoming increasingly important is problems associated with fragments of cottonseed that remain in cotton bales after ginning. These seed coat fragments (SCF) can cause the yarn to break during spinning resulting in costly down time in the mill. In addition, when the yarn or fabric is dyed, the SCF absorb the dye differently than the cotton lint and cause discoloration that is undesirable in the finished product. There has been much research conducted in mills to deal with this contamination, and cotton breeders have attempted to engineer better cottons. Cotton gin machinery has been modified to prevent or remove SCF, but success has been limited due to the poor understanding of this contaminant. The purpose of this experiment was to determine the origin of SCF by tracking their formation in cotton processed through a typical sequence of gin machinery. As suspected, the majority of SCF were produced in the gin stand from immature and normal seed that were damaged or completely destroyed. Analysis of seed meats in seed cotton cleaner waste showed that a significant portion of SCF was formed before the gin stand. It was suspected that damage also occurred in the field. Results from this report will be vital to future research aimed at preventing or reducing SCF contamination in cotton bales. Implementation of this knowledge will help to increase the competitiveness of U.S. cotton.
Technical Abstract: High seed coat fragment (SCF) content in cotton bales causes processing problems in textile plants. This experiment was designed to determine the origin of SCF by tracking their occurrence through a conventional sequence of gin machinery. After the lint cleaner, lint contained an average of 12.25 SCF weighing 4.95 mg/g lint. The lint cleaner did not change the number of SCF in lint but the total weight was reduced by 6.4 mg SCF/g lint, which was similar to the weight found in lint cleaner waste (6.7 mg SCF/g lint). Larger SCF were found in the waste, so heavier SCF were removed from lint or broken into smaller SCF. These weights did not include the weight of lint attached to the SCF after removal from the sample which was highest after the lint cleaner (41%) and lowest in lint cleaner waste (10%). Seed meats found in the ginned seed indicated that 0.8% of seed was destroyed accounting for 32% of SCF formed in the gin stand. Small seed (d<3.6 mm) eliminated from the distribution by the gin stand were 2.3% of the total number of seed and accounted for 15% of SCF formed in the gin stand, assuming all were broken into SCF. There were 7% of seed damaged in the gin stand while remaining intact, but there was no estimate for SCF resulting from this damage. There were 4.5 mg SCF/g lint found in seed cotton at the gin stand feeder, and seed meats found in seed cotton cleaner trash indicated only 1.0 mg SCF/g lint was formed. Most seed meats (57%) were found in the first seed cotton cleaner, so much of the damage before ginning may have occurred in the field. The SCF content (total weight and average SCF weight) of seed cotton at the gin stand feeder was similar to the SCF content of ginned seed, so these were not a significant portion of those found in ginned lint. These results suggest that small/immature seed (d<3.6 mm) were more prone to damage as they passed through the gin stand. Seed destroyed in the gin stand was a major source of SCF along with seed that were only damaged in the gin stand.