Herbicide movement in air; by spray drift, movement with dust, or by volatilisation and redeposition, can potentially cause injury to non-target crops and native vegetation kilometres away from the site of application. Recent summer growing seasons have seen repeated herbicide-related injury to cotton crops, resulting in estimated economic losses of $10-$30 million dollars. Despite desktop modelling studies showing the potential for damage and numerous reports of herbicide injury non-target crops, actual measurement of off-site herbicide deposition in Australia is scarce.
- To provide baseline information about the aerial movement and deposition of group M (e.g. glyphosate) and group I (e.g. 2,4-D) herbicides in the Macquarie Valley during summer when cotton injury has been previously documented;
- To assess the sampling efficiency, cost effectiveness and suitability of three different methods for measuring aerial herbicide deposition and
- To determine primary routes of transport and periods of higher relative hazard so recommendations can be made for practice change and ongoing monitoring
What we are doing
- Weekly aerial deposition samples have been taken from 6 sites in the Macquarie Valley from Dec 2019-Mar 2020.
- Measuring the load of 2,4-D and glyphosate being deposited per hectare
- Deposition can be related to toxicological thresholds (e.g. deposition rate at which growth of non-target plants is affected)
Outputs and/or outcome
- Primary routes of transport (e.g. spray drift or deposition in dust or rain) and periods of higher relative hazard to non-target plants identified.
- Information used to formulate specific recommendations for practice change and ongoing monitoring to manage risk.
- Trust and cooperation between the regulator (EPA) and industry improved whilst herbicide use for sustainable agricultural production maintained
Partners (or collaborators)
NSW DPI Livestock systems
Wollongbar Primary Industries Institute