Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 3, 2006
Publication Date: December 1, 2006
Citation: Byler, R.K. 2006. Historical review of moisture content effect on fiber length and moisture addition to seed cotton before ginning. Journal of Cotton Science. Vol. 10: 300-310. Interpretive Summary: The moisture content of harvested seed cotton must be reduced in some instances to enhance processing at a gin plant, thus gins have artificial drying equipment. Research was reviewed related to the issue of the proper moisture content of cotton for ginning and the results if cotton was ginned when it is too dry. If the lint portion of the harvested cotton was too dry damage to the lint during ginning increased resulting in broken fibers. During periods of good weather during harvest the seed cotton was drier than optimum for ginning plus research found that drier cotton is easier to clean which often resulted in better grades so ginners tended to dry the seed cotton more than necessary. Several studies showed that the currently used measures of fiber length respond only slightly to the fiber damage but the impact on yarn strength was more apparent. Researchers are working to improve fiber measurements so that the damage done to the fiber by ginning at low moisture content can be better detected. Several ginning studies documented the possibility and advantages to increasing the moisture content of lint before ginning using either water vapor or water spray. These water applications resulted in better fiber properties and would allow ginners a better way of dealing with seed cotton which arrives at the gin drier than optimum for ginning. The improved fiber quality will enhance cotton marketability.
Technical Abstract: Seed cotton drying equipment was adopted in the U. S. during the 1940's. Problems with fiber length associated with excessive drying were observed almost immediately. At first, high drying temperatures were blamed for the damage but later it appeared that the fiber moisture content (mc) was the more important factor. Increased drying consistently improved grade, mostly due to the improved cleaning efficiency, and the impact on fiber length was less consistently observed. However, the fiber length measurement used in pricing, staple, was often, but not always, improved when ginning at higher mc. Significantly lower yarn strength often resulted from cotton ginned at lower mc even when the staple length had not been affected significantly. Reviewed literature consistently supported ginning at moisture content levels above 6% to preserve fiber length quality but current data shows that this goal is not being achieved. It has been shown that during periods of good weather the seed cotton is drier than desirable for ginning without additional drying. Several studies supported the practice of adding moisture to low moisture seed cotton, either as a vapor or liquid spray, before the gin stand in order to better preserve the fiber length quality.