Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: February 2, 2010
Publication Date: April 1, 2010
Citation: Baker, K.D., Hughs, S.E. 2010. Optimizing Spindle Speed for Cotton Pickers. National Cotton Council Beltwide Cotton Conference. p. 551-557. 2010 CD. Interpretive Summary: Spindle picking has become the preferred method of harvesting most cotton in the U.S. Improvements to the cotton harvester have primarily focused on increased speed in order to reduce the cost of harvesting and reducing head weight. As the spindle speed has increased, cotton fibers can wrap more tightly around the spindle. As spindle diameter decreases, cotton fibers will wrap around the spindle more and will also become tighter on the spindle. As spindle length decreases, cotton plants must be further compressed as they pass through the picking zone. These changes have resulted in a general decrease in cotton fiber quality, particularly regarding spindle twists, preparation, and neps. Data from this study confirms that the amount of trash, spindle twists and neps increases as the spindle speed is increased from 2000 to 3000 rpm and again from 3000 to 4000 rpm.
Technical Abstract: Field tests were conducted for the 2006, 2007, 2008 and 2009 crop years by the USDA, Agricultural Research Service, Southwestern Cotton Ginning Research Laboratory in Mesilla Park, New Mexico. Three cotton varieties were grown under furrow-irrigated conditions in southern New Mexico and harvested with a modified 1-row cotton picker each year using a ground speed of 0.85 m/s (1.9 mi/hr) and spindle speeds of 2000, 3000, and 4000 rpm for the 2006 and 2007 crops and spindle speeds of 2000, 2300, 2700 and 3000 rpm for the 2008 and 2009 crop. The tests were replicated 4 times. Stalk losses in the field were significantly greater at a spindle speed of 1500 rpm than for speeds of 2000 rpm or greater for all varieties. This indicates that a spindle speed of at least 2000 rpm is needed for the picker to adequately function. Stalk losses were greater with speeds of 3000 and 4000 rpm than for a speed of 2000 rpm with the Pima variety. The number of spindle twists in a 1000 g seed cotton sample and the percent of seed cotton that was spindle twists was greater for the 3000 and 4000 rpm spindle speeds than for the 2000 rpm spindle speed. Both measurements of spindle twists in seed cotton nearly doubled when spindle speed increased from 2000 to 3000 rpm and then increased more when spindle speed increased to 4000 rpm. The increase in spindle twists makes preserving fiber quality while ginning a greater challenge. An analysis of trash collected from ginning showed no significant differences among treatments. HVI classing data also showed no significant differences among treatments except for upland lint samples collected before lint cleaning. In these samples, there were higher levels of trash with spindle speeds of 3000 and 4000 rpm than with a speed of 2000 rpm. The differences were no longer significant for samples collected after lint cleaning. In 2006, differences were significant for AFIS nep count and short fiber count in the raw stock from the bale with all three varieties. Both neps and short fiber content increased when spindle speed was increased from 2000 to 3000 rpm and from 3000 to 4000 rpm. These nep count and short fiber differences were diminished, but did not disappear as the fiber was further processed. For AFIS dust count and trash count, significant differences were noted in the raw stock, with higher levels of dust and trash at speeds of 3000 rpm or greater. Differences in dust count and trash count disappeared as the fiber was further processed.