ABSTRACT

Organic cotton production requires alternatives to harvest 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 chemically defoliated controls. Other fiber properties were not greatly affected. Spinning and yarn properties were mostly unchanged. Rapid desiccation following thermal treatment makes it possible to harvest two days after defoliating. Foreign matter content of seed cotton did not decrease significantly after seven days, indicating completion of plant response. Insect mortality and the possibility of early harvest were additional benefits observed with thermal defoliation.