Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/9/2004
Publication Date: 6/1/2004
Citation: Funk, P.A., Armijo, C.B., McAlister, D.D., Brashears, A.D., McGuire, M.R., Lewis, B. E., Hutmacher, R.B., Roberts, B.A. 2004. 2003 Thermal defoliation trials. In: Proceedings of the National Cotton Council. 2004 Beltwide Cotton Conferences, January 5-9, 2004, San Antonio, Texas. 2004 CDROM. p. 755-759. Interpretive Summary: Non-chemical crop production tools have grown in importance with the rapid growth in organic agriculture taking place in America. Labeling rules restrict chemical usage when producing organic cotton. Furthermore, chemical usage is restricted 3 years in advance of the production of any crop labeled "organic." Therefore, restrictions apply to cotton being grown on land that will eventually be certified for the organic production of other crops. These laws even apply to adjoining land if buffer zones and runoff diversions can not prevent the unintended application of, or contamination by, a prohibited substance. Thermal defoliation is an important tool for preserving fiber quality and crop value, controlling insect pests, and managing harvest operations for organic cotton and for cotton associated with the organic production of other crops. Producers can increase the value of their crop without damaging the fiber.
Technical Abstract: Organic cotton production requires alternatives to havest aid chemicals for crop termination and fiber quality preservation. In these trials, a self-propelled two-row thermal defoliation apparatus was tested in spindle picked and stripper harvested cotton. HVI classing data for thermal, chemical, and untreated control plots were compared. Fiber property data from similar trials in 2002 were presented where data from 2003 trials were not available. Leaf and color grades were improved, thereby increasing fiber value as compared to untreated and chmically defoliated controls. Other fiber properties were not greatly affected. Spinning and yarn properties were mostly unchanged. Rapid desiccation following thermal tretment makes it possible to harvest 2 days after defoliating. Foreign matter content of seed cotton did not decrease significantly after 7 days, indicating completion of plant response. Insect mortality and the possibility of early harvest were additional benefits observed with thermal defoliation.