Spindle Speed Optimization for Cotton Pickers

Abstract. There is concern that changes to the operating speed and size of spindles on cotton picker harvesters over the years have resulted in a general decrease in cotton fiber quality, especially spindle twists, preparation, and neps. Previous research showed that spindle speeds of 3000 and 4000 rpm had more detrimental effects on picker stalk loss, trash levels in seed cotton, and cotton fiber quality than a spindle speed of 2000 rpm. This study was conducted to check fiber quality effects between 2000 and 2800 rpm in order to further define the optimum spindle speed range. Field tests were conducted for the 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 one-row cotton picker each year using a ground speed of 0.85 m s-1 (1.9 miles h-1) and spindle speeds of 2000, 2200, 2500, and 2800 rpm. The tests were replicated four times. No significant differences in stalk losses in the field were found. Significantly more trash was present in seed cotton picked with spindle speeds of 2200, 2500, and 2800 rpm than in seed cotton picked with a spindle speed of 2000 rpm. Differences in trash content were eliminated by seed cotton cleaning (same for all treatments). HVI classing data showed no significant differences among spindle speed treatments. Differences due to spindle speed for AFIS nep count, short fiber count, trash count, dust count, and seed coat nep count were non-significant at each of the four locations tested in the yarn preparation process. Results from open-end spinning tests, including opening and cleaning waste, total card waste, ends down, yarn strength, yarn elongation, neps, thick places, and thin places showed no significant differences due to spindle speed. Based on these results, the 2000 rpm spindle speed is optimal because trash in the seed cotton is reduced which reduces ginning costs; however; only minimal differences are present at spindle speeds up to 2800 rpm.