The issue
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.
Objectives
- 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 EPA
NSW DPI Livestock systems
Contact
Mick Rose
Wollongbar Primary Industries Institute