Fire Helps Defoliate Cotton Without Chemicals

Process is proven and economic field trials are planned for 2006. Dan Crummett

Published on: Jan 6, 2006

USDA research in California, Texas and New Mexico over the past several years shows cotton can be defoliated with propane-fired burners and harvested two days later—with no additional chemicals. The process also efficiently kills all stages of insect infestation as a plus.

Agricultural Research Service engineer Paul Funk, Las Cruces, New Mexico, has lead the effort to design a thermal cotton defoliator and says he and his colleagues have tested a machine successfully on cotton fields in California, New Mexico and Texas.

The machines heat air to 380 degrees Fahrenheit and push it through the cotton canopy bursting the cells in leaves and some stems. Leaves show the affect of the treatment within hours and begin falling from the plant by the next day. Funk says defoliation isn't as complete as with chemicals, but leaves remaining on the plant are dry and brittle—allowing harvest. Also, he says there's no loss in cotton quality with the process.

This two-row defoliator uses propane burners to heat air to thermally defoliate cotton in a single pass. Tests show the process does not affect cotton quality and makes harvest available two days after treatment. 

"This works on windy days and we have never had to make a second treatment," he explained to a small group of agricultural reporters Thursday in San Antonio. The gathering was part of the Beltwide Cotton Conferences and preceded a formal presentation on the process scheduled for Friday.

The researcher says the process is of extreme interest to those growing cotton for the organic market, and others who want to reduce their chemical bills.  

"The costs of inputs are roughly equivalent to chemical defoliation," he explains, but the application costs have not been studied thoroughly. This year will see a new test machine capable of defoliating five acres per hour in the fields with researchers doing economic feasibility studies on it. 

Funk credits the Propane Education and Research Council for funding that has helped make the research a success.

For more information on the process and research call (314) 746-1928.