Non-shielded dual-spray technology for application of herbicides in sugarcane production systems

Abstract

In 2009 the Queensland Government introduced a suite of environmental regulations aimed at reducing the amount of herbicides, fertilizers and sediment entering the Great Barrier Reef Lagoon. Staff from the Queensland Government were conducting spray-drift management workshops throughout the Wet Tropics region of far-northern Queensland when growers attending the workshops asked if it was possible to design a spray system for existing Irvin-type booms that could apply glyphosate to the interrow of sugarcane using air-induction nozzles, eliminating the need for shields or hoods. They thought that this would assist them to comply with the new regulations, as well as generally reduce use of residual herbicides. Early design and static testing commenced in October 2010 with various combinations of spray nozzles and spray bar angles tested. Prototype engineering drawings were also completed. No evidence of glyphosate toxicity to sugarcane was detected in replicated trials using the ‘Dual Herbicide Sprayer’ (DHS) in the 2012-2013 growing season. Yield data were not significantly different between plots where glyphosate was applied in the interrow and the standard grower practice of a mixture of diuron and paraquat applied over the entire paddock. Other indicators of phytotoxicity used in the trials, including stalks per metre of row, Brix, CCS, stalk diameter and height, showed no significant differences among treatments. A user manual for the DHS has been developed and is available free-of-charge to equipment manufacturers and growers. Based on sales of spray bars and new sprayers, approximately 11,000 ha are now being sprayed using DHS technology. © 2019 Australian Society of Sugar Cane Technologists. All rights reserved.