Spray drift from agricultural pesticides can cause crop protection chemicals to be deposited in undesirable areas. This can cause serious consequences such as damage to sensitive adjoining crops and susceptible off-target areas, environmental contamination, illegal pesticide residues, and health risks to animals and people.
Spray drift and risks connected with application of pesticides in agriculture are attracting increased attention from the general public as well as the scientific community. In 2003, ILVO started a five-year-long collaboration with Ghent University and Katholieke Universiteit Leuven to study drift and drift reduction from field crop sprayers
Indirect drift experiments (spray quality and wind tunnel measurements) and direct drift experiments (in the field) were performed, and drift models developed. These experiments revealed the effect of spray application technique, droplet characteristics, buffer zones, meteorological conditions, spray liquid properties, border structures, and crop characteristics on drift from field crop sprayers. Various spray application factors were also evaluated, such as spray boom height, air support, nozzle type and pressure and driving speed. The results indicated that indirect drift measurements can be a valuable alternative to field drift experiments.
Katholieke Universiteit Leuven developed a validated 3-D Computational Fluid Dynamics (CFD) mechanistic drift model. This model can be used to systematically study different influencing factors. This model was reduced to a fast and accurate 2-D diffusion advection model, which is a useful hands-on drift prediction tool.
This project resulted in drift measuring protocols and advanced measuring techniques, a unique drift database useful for spray drift risk assessments, and spray drift models. We developed measures to minimise the negative effects of spray applications on the environment. These measures will raise farmer’s and manufacturer’s awareness of good agricultural practices.
The experiments and the models revealed the most influential spray application factors to be the fraction of small droplets and the spray boom height. Meteorological conditions and crop characteristics significantly affect the amount of spray drift. Drift can be greatly reduced by using screens or buffer zones.
The protocols, data and models now available will help to further understand and reduce the complex phenomenon of spray drift. This information is available for manufacturers, farmers and policymakers.
Ghent University, Department of Crop Protection
Catholic University of Leuven, BIOSYST-MeBioS
Donald Dekeyser, David Nuyttens