Comparing cotton fiber quality from conventional and round module harvesting methods

Abstract

Listen

Translate article

The introduction of the John Deere 7760 spindle harvester to the Australian cotton industry in 2008, with on board module building capacity producing round modules, has led to the rapid uptake of this technology by growers due to a reduction in labor requirements. There have, however, been anecdotal reports from cotton classing facilities and growers that the quality of cotton harvested by the John Deere 7760 is different and more variable compared to cotton harvested by the conventional spindle basket harvesting and separate module building method. The aim of this research was to compare the average fiber quality and the variability of quality between bales of cotton produced by these two harvesting methods. Four fields located in the southern and central cotton growing areas of Australia were planted with two popular upland varieties. Alternate groups of rows across each field were harvested using either the round module or conventional basket harvesting method, with harvested seed cotton ginned at the same gin. Fiber samples were assessed for quality attributes typically used to class and value cotton in Australia. There was no significant difference of average results between the two harvest methods for High Volume Instrument (HVI) determined upper half mean length and bundle strength. However, HVI micronaire was marginally yet significantly lower and HVI reflectance higher for fiber from the round module system, which was attributed to the round harvesters being able to harvest more fiber (including immature fiber from the top of plants) and less trash. The small difference in reflectance, however, did not translate into a practical difference, with there being no significant difference measured between the two harvesting systems for visually determined color and leaf grade. The normalized variability (% coefficient of variation) of fiber quality between bales was greater for the round module system, which was attributed to less blending during the sequential ginning of round modules in contrast to the vertical building of equivalent multiple (round module) layers of seed cotton in larger conventional modules that undergo more blending when fed longitudinally into the gin. While the round modules in this research were harvested and ginned according to industry standards and in sequence, less than favorable in-field conditions and out-of-sequence ginning would more than likely compound the variation in fiber quality between bales. The impact of these variables on fiber quality would have significant practical implications, which will require further investigation.