Improving our understanding of the persistence, bioavailability and crop toxicity risks of soil residual herbicides

Abstract

The use of residual herbicides for weed control in cropping systems with diverse crop rotations requires a thorough knowledge of herbicide behaviour to minimise the risk of plant-back crop damage. This is especially the case when multiple mode-of-action groups are applied to counteract the threat of herbicide resistant weeds or populations. Adding to this challenge is an increasing probability of more extreme weather events, including more frequent or longer drought events, which can have strong effects on herbicide persistence. Although growers and advisors often have a good qualitive and experiential grasp of herbicide behaviour and plant back risk, more quantitate and site-specific information could help refine planning and operational decisions to avoid costly crop damage.
This presentation introduces a new project entitled ‘Geospatial analytics to predict the impact of residual herbicides on establish and yield’ that aims to validate several tools to help better understand the likelihood of herbicide carryover and potential crop damage. The project will develop and couple geospatial models of herbicide persistence with ‘pedo-transfer functions’ and leaf tissue analysis to quantify crop toxicity risk. The presentation will outline the proposed project framework and discuss some recent findings from field experiments to illustrate potential practical implications for grain growers and advisors.