Comparing dryland cotton upland fibre quality from on-board spindle and stripper harvesting systems

Abstract

On-board spindle and brush type stripper round module harvest systems were evaluated on commercial field scale for dryland Upland cotton in Australia over two harvest seasons. Observations on harvester performance, including harvesting efficiency, harvest loss, seed cotton yield and lint turn out were conducted at three locations, during the 2017 and 2018 cotton growing seasons, with a single variety. Fibre quality was measured by High Volume Instrumentation (HVI™) and Advanced Fiber Information System (AFIS) and analysed to determine if there were any significant differences between the two harvesting systems. The stripper harvesters had higher productivity (i.e. hectares per hour), harvested more material with lower harvest loss than the spindle harvesters. The seed cotton harvested by the stripper systems contained plant material which resulted in a lower lint turn out than the spindle harvester although the yield in bales ha−1 was still higher. There were no significant differences in fibre quality as measured by the HVI except for colour and trash. The significant differences in colour and trash did not affect the economic return to the grower as the visual colour and trash grades were below, i.e. better than, the Australian base grade. There were also no significant differences in the fibre quality as measured by AFIS. It is hypothesised that the reasons for this was due to the appropriate timing and application of defoliation, harvesting when moisture content ≤ 12%, reduced leaf allowing for gentler ginning and mature fibre.