Home » Volume 10 / 2006 » Issue 4 »
Harvesting and Ginning a Cotton with a Fragile Seed Coat
Carlos B. Armijo, Greg A. Holt, Kevin D. Baker, Sidney E. Hughs, Edward M. Barnes, and Marvis N. Gillum
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Seed coat fragments that remain in fiber after the ginning process cause problems during the spinning process and ultimately affect the quality of finished goods. An experiment was conducted to determine the effect of harvesting and saw ginning methods on an upland cultivar known to have fragile seed coats. Three harvester (picker) treatments examined the effects of spindle diameter and spindle speed. Four saw ginning treatments examined the affects of the type of seed roll box and seed roll density on seed coat fragments in the ginned fiber. When compared with a commercial cultivar, the cultivar with a fragile seed coat contained many favorable fiber properties, but seed coat nep count and visible foreign matter content were higher. Fiber length was longest and short fiber content and seed coat nep count were lowest with the 13-mm (1/2-in) spindle compared with the other harvesting treatments. Increasing spindle diameter to 16-mm (5/8-in) and spindle speed of the 16-mm spindle by 45% increased seed coat nep count. In addition, fiber length was longer with the traditional and conveyor-tube seed roll boxes than with the paddle-roll box. Ginning with the conveyor-tube box at 40% of the normal conveyor-tube box rate produced the lowest short fiber content and the best HVI color grade. The paddle-roll box had the fewest seed coat neps and lowest total trash and visible foreign matter content, but it also had the lowest AFIS fiber length and the highest short fiber content.