Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/23/2006
Publication Date: 10/20/2006
Citation: Funk, P.A., Armijo, C.B., Brashears, A.D., McAlister III, D.D., Showler, A., Fletcher, R.S. 2006. Cotton harvest preparation using thermal energy. LP Gas Global Technology Conference. 19th World LP Gas Forum, October 17-20, 2006, Chicago, IL. 2006 CDROM. Interpretive Summary: The yield and fiber value of cotton prepared for harvest by conventional chemical and experimental heat treatments is compared over two years from three states, six locations and seven varieties. Fiber value and yield were not significantly different by treatment. To optimize harvest timing with thermal defoliation, various intervals from two to 89 days between treatment and harvest were compared. Fiber value was constant but yields were slightly lower when harvesting less than seven days after thermal treatment. However, early harvest may prevent weather related losses such as from a hurricane. The experimental heat treatments eliminate insect pests by removing their food supply. A single application is sufficient to prevent aphid and whitefly stickiness. Heat treatment can be applied in combination with chemical boll openers to enhance yields. Thermal defoliation is an effective harvest preparation tool that complies with organic labeling rules.
Technical Abstract: Cotton is prepared for mechanical harvest using desiccant and defoliant chemicals. Conventional chemical defoliation is not effective immediately, it requires a period of good weather, and it is restricted in organic production. This study was conducted to determine what impact thermal defoliation has on fiber value, yield and gross returns. A thermal defoliation machine that used propane to heat treatment air was tested on several varieties at various locations in three states over two years. A mixed statistical model was used to compare thermal to conventional chemical defoliation and harvesting two or three days after treatment to harvesting two or three weeks after treatment. There were no statistically significant differences in yield or value between treatments or harvest dates. Thermal defoliation does not negatively impact fiber value or yield, and thermally defoliated cotton may be harvested early without reducing gross returns.