Note: You are reading this message either because you can not see our css files, or because you do not have a standards-compliant browser.

LOGO: Journal of Cotton Science


Effects of Defoliation Timing and Desiccation on Net Revenues from Ultra-Narrow-Row Cotton

Authors: James A. Larson, C. Owen Gwathmey, and Robert M. Hayes
Pages: 204-214
Economics and Marketing

Criteria for profitable timing of cotton (Gossypium hirsutum L.) defoliation have not been determined for ultra-narrow-row cotton (UNRC). This study evaluated the effects of alternative defoliation timing and desiccation treatments on net revenues for UNRC. Cotton cv. PM 1218 BG/RR was planted in 25.4-cm rows at Milan, TN, in 2001, 2002, and 2003. Two defoliation timing criteria using heat-unit accumulation after node above white flower (NAWF) were evaluated. Main plot treatments were the standard defoliation criterion of NAWF = 5 plus 472 degree-days (DD) (base 15.6 °C) and a later defoliation criterion of NAWF = 2 plus 472 DD. Three desiccation treatments (paraquat, sodium chlorate, or no desiccant) were the subplot treatments and were applied 14 ± 1 d after each defoliation. Plots were harvested with a finger-type stripper 8 ± 1 d after each desiccation treatment. Price differences for fiber quality were calculated using fiber quality data measured from the experiment and North Delta spot price quotations. Net revenues were estimated using lint yields, price differences, and desiccation costs. Across years and desiccation treatments, delaying defoliation until NAWF = 2 plus 472 DD increased lint yield and net revenue by 9% relative to the standard NAWF = 5 plus 472 DD criterion. Applying a desiccant after defoliation did not adversely affect lint yield, price difference or net revenue, but desiccation slightly increased gin turnout, which may be an economic benefit to the ginner. Paraquat did not differ from sodium chlorate in effects on lint price differences and revenue. There were no significant timing-by-desiccation effects. Since seedcotton samples were not put into modules, these desiccation results may not apply to cotton stored in modules.