Effect of Harvesting Methods and Cotton Fiber Maturity on Yarn Quality

Large-scale tests undertaken by AgriLife extension in Lubbock were the base for our investigations. The tests were conducted in eight locations over a three years period. Each test consisted of 4 large plots. Each large plot was divided into two blocks. Each block corresponded to one module. Half of the blocks were harvested with a stripper with field cleaner and half with a picker. The stripped cotton was ginned with the usual industrial sequence for stripper harvested cotton. The gins used a less aggressive ginning sequence for the picker harvested cotton. This totaled 64 modules. From each module, one bale was purchased. The bales were sampled and fiber quality determined. Then, spinning tests were performed.

Picker harvested cottons have on average better fiber properties:

• Micronaire: +0.17 (+4.3%)
• UHML: +0.01 inch (+0.7%)
• UI: +0.5 % (+0.6%)
• Reflectance: 0.6 % (+0.8%) and Yellowness: -0.3 (-3.2%)
• Neps: -130 count/g (-29.0%)
• UQL: +0.01 inch (+1.4%)
• L(n): +0.03 inch (+3.3%)
• L(n)CV: -2.3 % (-4.3%)
• SFC(n): -2.5% (-8.6%)
• VFM: -0.8% (-35.9%)
• Fineness: +2.9 mtex (+1.9%)
• IFC: -0.7 % (-7.3%)
• MR: +0.01 (+1.2%)

 Picker harvested cottons have on average better carded ring spun yarn quality:

• Opening waste: -0.5% (-15.5%)
• Card waste: -0.7% (-16.5%)
• CVm: -0.39% (-2.4%)
• Thin places: -4 count/km (-18.8%)
• Thick places: -49 count/km (-18.4%)
• Neps 200%: -99 count/km (-24.4%)
• IPI: -151 count/km (-21.9%)
• Hairiness: -0.16 (-2.9%)

In conclusion, for lower micronaire cottons, picker harvesting is clearly beneficial. It results in better fiber quality; more importantly, it results in better yarn quality for all evenness-related parameters. However, in 2010-11 micronaire readings (≥ 4.0) were much higher than in 2008-09 and 2009-10. In these conditions, it appears that picker harvesting does not benefit yarn quality.