Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: 9/12/2009
Publication Date: 9/15/2009
Citation: Boman, R.K., Kelley, M., Keeling, W., Wanjura, J.D., Baughman, T. 2009. 2009 High plains and northern rolling plains cotton harvest-aid guide. Texas AgriLife Extension Service, College Station, TX. p. 1-17. Available: http://lubbock.tamu.edu/cotton/pdf/2009HarvestAid.pdf. Interpretive Summary: Most cotton grown in the US is prepared for harvest by applying chemical defoliants and desiccants which help remove leaves from the plants, open bolls, and condition the plants for machine harvest. The selection and application timing of these chemicals is of critical importance to Texas cotton producers in their efforts to optimize yields and quality. If applied too early, yields may be reduced and quality severely damaged. If applied too late, late season weather may limit the efficacy of the chemicals and result in wasted labor and chemical costs. This manuscript presents the results of extension field trials on evaluating the efficacy of commercially available harvest aid chemicals in the Texas High Plains and Northern Rolling Plains regions. In addition, considerations for machine harvesting with brush-roll strippers and spindle pickers are made in terms of maintenance requirements, pre-harvest configuration and adjustment, and infield operation. This document is distributed directly to producers through extension meetings and through the Texas Agrilife website (http://lubbock.tamu.edu). Approximately 1000 copies are distributed annually.
Technical Abstract: Harvest-aid chemicals are generally applied to hasten harvest of a mature crop, and to reduce potential preharvest losses of lint yield and fiber quality. Proper use of harvest aids can result in earlier harvest, preservation of fiber quality, and fewer seed quality reductions due to field exposure. Weathering losses in the High Plains can result in considerable reduction in dollar value of the crop unless measures are undertaken to protect yield and quality potential. This is especially true for open boll picker-type varieties and lesser storm-proof stripper types. Timing of harvest-aid chemical applications is critical and different methods and considerations for determining the correct time may be utilized. Premature harvest-aid applications can result in loss of lint and seed yield and reduced fiber quality which ultimately can result in reduced profits or greater economic losses. Although studies indicate that maximum yield and quality occur at different stages, correct timing of harvest-aid applications can enable producers to obtain optimum yields of high quality lint and seed. However, even when applications are made under ideal conditions, inclement weather or lack of available machinery and/or labor can delay harvest for several days or longer. Delayed harvest timings can have adverse effects on both yield and quality of lint and seed. Cotton producers in the Texas High Plains face difficult decisions at harvest time that have profound impact on yield and quality. A comprehensive 3-year project (2000-2002) to address the fundamental data requirements of stripper harvested cotton was conducted in the Texas High Plains near Lubbock. The field was planted to a storm-proof variety, Paymaster 2326RR, and the treatment structure included harvest-aid chemical termination with varied harvest dates. Lint yields were reduced with later harvest dates one out of three years. Also, results from HVI analyses indicated significant reductions in fiber quality when harvest was delayed, most notably were length, strength and color grades. These fiber quality reductions subsequently resulted in lower lint loan values and ultimately, lower net values per acre. When considering planting seed quality, later harvest dates tended to reduce germination percentages two out of three years. This is an important consideration for individuals producing planting seed for companies or for those that retain seed for planting next year's crop. Even though a storm-proof variety was utilized during this study, the results indicate that significant reductions in lint yield, HVI fiber quality, economic returns, and seed quality can occur if harvest is delayed. Greater losses may be incurred with delayed harvest if a variety with a lesser degree of storm resistance is produced. Research results stress the importance of timely harvest aid applications and subsequent harvest for optimizing yield and fiber quality for greater net returns.