Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/5/2008
Publication Date: 5/29/2008
Citation: Funk, P.A. 2008. Preparing for harvest without chemicals. National Cotton Council Beltwide Cotton Conference, January 8-11, 2008, Nashville, TN. p. 72-77. 2008 CDROM.
Interpretive Summary: This paper presents research results from seven years of field trials conducted in four growing regions in three states by summarizing findings published in several journal articles and conference proceedings. There were no differences in fiber quality and value when using heat instead of defoliant chemicals. Yields were not significantly different. Using heat to defoliate cotton makes it possible to harvest in 24 hours, an advantage over chemicals (which often take ten days) if bad weather is threatening the crop. Heat can be applied regardless present wind speed or expected future precipitation and temperatures. Heat also kills insect pests responsible for sticky cotton. While the cost of fuel for thermal defoliation is equivalent to the cost of defoliant chemicals (both track petroleum prices) the application cost is expected to be higher, though data is not yet available.
Technical Abstract: New environmental laws may someday restrict defoliant chemical application. To prepare for this possible challenge experimental thermal defoliators were operated in California, New Mexico and Texas from 2001 through 2007. This paper summarizes findings from extensive trials in a variety of field conditions and cultivars. Physiological studies showed the efficacy of thermal defoliation and its impact on yield and harvest timing. Fiber quality studies indicated no damage to lint value. Entomological studies demonstrated reduced late season pest populations. Harvest is possible within hours of treatment. Fuel costs are similar to chemical costs.