Spindle Diameter Effects for Cotton Pickers

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 cotton fiber quality than a spindle speed of 2000 rpm. Field tests were conducted for the 2011, 2012, and 2013 crop years by the USDA, Agricultural Research Service, Southwestern Cotton Ginning Research Laboratory in Mesilla Park, New Mexico. Three cotton varieties were grown each year under irrigated conditions near Las Cruces, New Mexico, and harvested with cotton pickers equipped with spindles having diameters of 1.27, 1.43, and 1.59 cm (1/2, 9/16, and 5/8 in.), using a ground speed of 0.85 m s-1 (1.9 mi h-1). Spindle speeds were 2000 rpm in each case. Pickers with larger spindle diameters had lower stalk loss and sometimes had lower foreign matter levels in the seed cotton as well as in the ginned lint. These foreign matter levels significantly affected HVI foreign matter content and leaf grade. HVI classing data other than foreign matter content and related leaf grade showed no significant differences among spindle diameter treatments. AFIS nep count, short fiber content, trash count, dust count, and seed coat nep count showed no significant differences due to spindle diameter treatments or interactions. Results from ring spinning mini-tests, including skein breaking strength, skein count, skein count-strength product (CSP), yarn strength, yarn elongation, neps, thick places, and thin places also showed no significant differences due to spindle diameter. Based on these results, the picker unit with 1.59 cm (5/8 in.) spindles was optimal, but differences in performance were not large. Keywords: Fiber quality, Harvesting.