Accurately quantifying the magnitude and subsequent implications of off-target transport of pesticides via spray drift is critical to estimating exposure for ecological risk assessment and inferring potential spray drift impact to adjacent crops. Past work with this aim has included field, wind tunnel, and laboratory studies examining the contribution of environmental conditions, spray equipment, and spray mix (active ingredient and/or formulation) on the potential extent of off-target transport. However, there is limited research focused on better understanding factors affecting deposition on a more finite spatial scale such as the physical properties of intercepting objects that may affect directly adjacent airflow and the trajectory of the spray particles entrained. Regulatory risk assessments typically assume 100% drift interception and do not account for the unique physical properties of individual plant species/types.  Improved modelling of plant canopy interaction with pesticide particles entrained in airflow has the potential to improve scoping and design of non-target spray drift studies and to inform the risk assessment process. The aim of this work is to improve the understanding of pesticide spray drift particle interactions with plant canopies and the relative capture efficiency of different canopies. This presentation demonstrates an application of ANSYS CFX (a computational fluid dynamics (CFD) modelling tool) to estimate the capture efficiency of various plants receiving pesticide spray drift from applications made in a wind tunnel. The CFD model includes realistic, high-resolution, 3D plant geometry generated using photogrammetry freeware. The method for creating a robust model is the topic of a companion poster. Model-predicted plant canopy efficiencies are compared to measured canopy interception obtained in wind tunnel experiments.

Computational fluid dynamics modelling for plant canopy interception of pesticide spray droplets

256th National Meeting (2018)

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