Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 7/14/2008
Publication Date: 7/15/2008
Citation: Faulkner, W.B., Wanjura, J.D., Shaw, B.W., Hequet, E.F. 2008. Effect of harvesting methods on fiber and yarn quality from irrigated cotton on the High Plains. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)Meeting. June 29-July 2, 2008, Providence, RI. Paper No. 083283. Interpretive Summary: Historically, the majority of cotton grown on the High Plains of Texas has been stripper harvested. Strippers indiscriminately gather seed cotton, sticks, stems, leaves, and other foreign material from the plants during harvest leading to lower lint bale quality and leaf grades. Discounts from spinning mills for lower grade cotton and the need to compete in the global cotton market with high quality, clean, hand harvested cotton from countries such as India has caused High Plains producers to look to the cotton picker as an alternative harvesting method. Pickers use rotating spindles to pick locks of seed cotton from the plants leaving the majority of the foreign material gathered by strippers in the field. The initial capital expense for a cotton picker is often over two times greater than that of a cotton stripper. The objective of this work was to compare fiber and yarn quality from four varieties of cotton harvested on the High Plains using modern picker and stripper harvesters. Cotton samples harvested under the test treatments were ginned using a common machine sequence and fiber samples were analyzed for quality by the High Volume Instrument (HVI) method used by the USDA-AMS to grade cotton for market. The samples were also analyzed by the Advanced Fiber Information System (AFIS) method. The growing conditions during 2006 were different than for 2007 and resulted in the production of very immature fiber. In 2006, differences in fiber quality between harvesting methods were more pronounced due to the immaturity of the fiber leading to better returns for picked cotton. However, in 2007 fiber maturity was substantially improved and the difference in fiber quality between stripped and picked cotton was diminished resulting in reduced economic return for picked cotton. The results indicate that High Plains producers may realize an economic benefit from picking cotton rather than stripping, but that benefit is likely a function of fiber maturity.
Technical Abstract: Over a fourth of the cotton bales produced in the United States since 2002 have been produced in Texas, with most of that cotton coming from the stripper harvested High Plains region, and in recent years, Texas cotton production has represented almost half of all the US cotton production. As irrigation technology has improved and new varieties have been introduced on the High Plains, yields in the region have dramatically increased, sometimes reaching four bales/acre. Furthermore, foreign textile mills continue to raise their standards for fiber quality as cotton spinners are forced to compete with synthetic fibers. These increased yields and higher quality demands have the potential to make harvesting High Plains cotton with pickers an attractive option compared to the stripper harvester which collects substantially more foreign material with the harvested seed cotton. The objective of this research is to compare fiber and yarn quality from four varieties of cotton harvested on the High Plains using modern picker and stripper harvesters. Fiber quality indices were determined with HVI and AFIS instruments and were compared for cotton harvested with a spindle picker, a brush-roll stripper with a field cleaner, and the same stripper harvester without a field cleaner (in 2006 only). Each year, all samples underwent similar cleaning regimes during ginning. In 2006, micronaire, length, and length uniformity as measured by HVI were better for picker harvested cotton than for stripped cotton leading to a higher loan value and average sale price for the producer. In 2007, when growing conditions were better and fibers were more mature, differences in fiber quality parameters between picked and stripped cottons were less pronounced leading to less discrepancy in the value of cotton harvested. However, in 2007, differences in nep counts, short fiber content, and visible foreign matter between harvest treatments were distinguishable. The results of this study indicate that producers may realize greater fiber quality and lint value by using picker harvesters, but the magnitude of those differences may be a function of growing conditions and/or fiber maturity.