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Title: Bale Weight Changes Related to Bale Bagging - Testing and Modeling

item Byler, Richard

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/27/2008
Publication Date: 7/2/2008
Citation: Byler, R.K., Jordan, A.G. 2008. Bale Weight Changes Related to Bale Bagging - Testing and Modeling. ASABE Annual International Meeting. Paper No: 084087. 11 p.

Interpretive Summary: Cotton bales are placed in bags to protect them from contamination during handling and storage. Traditionally the bagging has been porous and the relatively dry cotton from the cotton gins gained weight during storage as the fiber gained moisture. This higher moisture content lint was actually stronger and better for spinning at mills. The trend recently has been the use of non-porous plastic based bags because they are lighter in weight and less expensive. The industry has asked that plastic bags be produced with holes to improve moisture gain during storage but many of these bags allow only low levels of moisture transfer. In this study bales were formed from relatively dry cotton and placed in selected bags made of cotton, burlap, and polyethylene with various predetermined hole patterns. The cotton and burlap bags were very porous and did not restrict weight gain by the bales. A mathematical model was developed for the weight change of bales in polyethylene bags which predicted the change based on the percentage of open area of the bag. This equation will allow bag manufacturers to know how many holes of a given size will be required to achieve a specified rate of bale weight change. The resulting bags will adequately protect the bales produced in the US while allowing a reasonable moisture transfer. This packaging will allow the US cotton industry to remain competitive in the worldwide market.

Technical Abstract: Cotton bales are placed in bags to protect them from contamination during storage and handling and newer less expensive bagging inhibits moisture vapor transfer. Cotton is often relatively dry when ginned and traditionally has gained moisture content, resulting in a better product for spinning, during storage in humid areas. The industry is interested in using less expensive bagging but with holes provided to increase moisture transfer. Universal Density cotton bales were formed with relatively dry lint and covered with different types of bale bagging materials. These bales were weighed periodically while being stored in a humid environment for more than two months. The bale coverings included coated woven polypropylene with and without holes, linear low density polyethylene film with different hole patterns, woven cotton, woven burlap, and no bale bagging. The bale weights were modeled using a nonlinear model exponential in time. The models were considered to fit the observed bale weight change well. The rate of bale weight change obtained from the regression was used to calculate a half time to equilibrium, in days, for each bagging type. This half time number will allow simplified communication of the effect bale bagging has on the rate of change of cotton bale weight during storage.