Modeling of drift during the application of phytosanitary products on low crops: Literature review

Résumé

During the spraying of low crops, large quantities of pesticides are transferred from crop-growing areas to the atmosphere, by drift inducing environmental impacts, human health problems and economic loses. To better understand this drift phenomenon, spray emission modeling, in combination with field tests, could be a suitable solution but modeling stills the most used approach. Thus, the scientific community developed mathematical and computational models to describe the complicated interactions between spray droplets and its environment considering the different involved parameters. The final objective is to determine pesticide transport with few field tests. Most of the developed models are Lagrangian models that use the principles of fluid mechanics based on simplifying assumptions regarding the description of the kinetics of particles and the effect of turbulence on the behavior of the droplets.

Existing drift models only consider the evaporation of the solvent, which is often water. They assume that there is a loss of pesticide by evaporation only if the drop reaches total evaporation. They also assume that the drops are isolated and that the effect of surface tension is neglected. Thus, evaporation is necessarily overestimated. Several results of those models show that drops smaller than
100 μm are the most sensitive to evaporation. This paper presents a bibliographic review describing some known drift models, particularly their calculation bases of evaporation, considering the diversity of hypothesis and drift principles characterization.