Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/4/2011
Publication Date: 4/25/2011
Citation: Kelley, M.S., Wanjura, J.D., Boman, R.K., Ashbrook, C. 2011. Harvest timing and techniques to optimize fiber quality in the Texas High Plains. In: Proceedings of the Beltwide Cotton Conferences, January 4-7, 2011, Atlanta, Georgia. p. 449-454. 2011 CDROM. Interpretive Summary: Cotton fiber quality is paramount to the sustained competitiveness of US grown cotton on the world market. Customers overseas use US cotton in ring spinning applications which demand higher standards than US base grades for fiber quality in terms of length, length distribution, fiber strength, fiber maturity, and foreign matter content. Research over the past few years on the Texas High Plains has shown that picker harvesters offer advantages with regard to fiber quality compared to the stripper harvester which is the predominate harvest method used in the region. Pickers are more expensive to own and operate and leave more un-harvested seed cotton in the field compared to strippers. This yield loss can translate into a substantial reduction in the revenue generated per acre for picker harvesters compared to strippers. The objective of this work was to investigate new harvesting techinques utilizing both picker and stripper harvesters which will improve fiber quality while maximizing yield for cotton grown under irrigated conditions in the Texas High Plains. Four harvesting treatments were investigated: 1) green picking followed by sequential picking (pick then pick), 2) green picking followed by sequential stripping (pick then strip), 3) conventional picking, and 4) conventional stripping. Results show that more foreign matter was collected by treatments with a stripper harvesting component (2 and 4) and resulted in higher ginning costs based on total incoming seed cotton weight. Harvest costs were higher for treatments that included a picking component. Fiber quality was generally improved for the picker harvested cotton compared to the stripper with regard to maturity and length. In 2009, there were no statistical differences by harvest method in net value to the producer but the highest net value was obseved for the conventional picking treatment which returned about $25 per acre more than the next highest treatment - conventional stripping. In 2010, net value for the pick then pick treatment was significantly lower than the other three treatments whch were not different. Highest net value was observed for conventional stripping in 2010 followed by conventional picking which returned about $22 per acre less.
Technical Abstract: Production conditions typical to the Texas High Plains region can produce cotton crops with high short fiber and nep content, both of which have a detrimental impact on ring spinning performance. Since Texas now produces nearly 50% of the US cotton crop annually, it is critical that research focuses on finding ways to maximize fiber quality in order to improve the competitiveness of US cotton on the world market. In 2009 and 2010, a joint project was conducted between research personnel from USDA-ARS and the Texas AgriLife Extension Service in Lubbock, TX, to compare various harvest timings and techniques. The objectives of this work were to 1) investigate differences in fiber quality and maturity of cotton harvested using conventional equipment (e.g. a spindle picker and a brush-roll stripper with field cleaner) at different levels of final crop maturity, and 2) evaluate the economic feasibility of using these new harvesting techniques in irrigated cotton. Treatments containing a stripper component had higher bur cotton yields, and therefore higher ginning costs, than those with picker components only. In 2009, no significant differences were observed among treatments for lint yield. However, in 2010, the pick then strip and the conventional strip treatments resulted in higher lint yield than the pick then pick treatment. After subtracting harvest aid, ginning and harvest costs, net value for the pick then pick treatment was significantly lower than all other treatments in 2010 but not in 2009. This was attributed to lower lint yield, lower loan values, and higher harvest costs. Loan values were observed to be affected more by harvest timing than by harvest machinery. Micronaire values were higher for the initial harvesting events than for the sequential or conventional harvest events in 2009 and 2010. The higher micronaire values resulted in lower loan values due to not being in the premium range of 3.7 to 4.2. Loan values can also be negatively influenced by higher color grades due to lint staining from the initial green picker harvest event if ginning is not performed within a relatively short period of time, as was observed in 2009. Based on these results, either conventional picker harvesting or conventional stripper harvesting may be employed for optimum yield and quality as opposed to green picked followed by picker harvesting. More research is needed to determine the benefit, if any, of the green pick harvest event in low micronaire situations.