Cotton harvesting effects on fiber and yarn properties

Twelve cotton varieties, selected for their maturity date from the 1968 and 1969 crops, were spindle picked and stripped and ginned with a laboratory gin. In 1969, one variety ('Auburn M') was hand-picked, and six trash treatments (leaves, sticks, stems, bracts, grass, and burrs) were added individually by hand to simulate the trash content of stripped cotton. Classer's grade and staple length, length by the Fibrograph, micronaire index, lint color, tenacity, elongation, and yarn strength were determined from the lint samples. Spindle-picked cotton had significantly higher tenacity, micronaire index, 50 percent span length, 2.5 percent span length, and yam strength than stripped cotton for the combined analysis. Stripped cotton had similar elongation values and significantly higher reflectance values than spindle-picked cotton for the combined analysis. Grades were lower for stripped cotton for both years. These results indicated that stripped cotton was a lower quality product than spindle-picked cotton. The addition of sticks to the hand-picked cotton tended to significantly lower elongation, 2.5 percent span length, and yam strength values. The added burr fragments tended to significantly lower 2.5 percent span length and yarn strength values. The presence of stems resulted in samples having significantly lower yarn strength. Grass resulted in significantly lower 2.5 percent span length values. Bracts and leaves had no effect on the fiber properties and yam strength. However, the leaf-treated cotton had the lowest grade. No apparent relationships were found among the different trash treatments for micronaire index index, reflectance, and 50 percent span length. The wood fibers from the sticks, burrs, and stems seemed to be a contributing factor for the reduced yam strength.