Dust drift during mechanical and pneumatic wheat sowing and insights into the physicochemical characteristics of the abraded dust

Abstract

BACKGROUND: During sowing, plant protection products (PPP)-laden dust particles can be abraded from coated seeds and emitted into the atmosphere. Drift of these particles is a very complex phenomenon and depends on many factors, including the physicochemical characteristics of the dust. Currently, the available data needed to obtain a better understanding of the phenomenon and to build a risk assessment tool remain very limited. In this study, new data on dust drift and on the physochemical characteristics of dust abraded from wheat seeds generated using a pneumatic and a mechanical seeder were obtained. These data will serve as input to optimize a much-needed computational fluid dynamics (CFD) model. RESULTS:The dust generated by the pneumatic seeder contained a greater volume of smaller particles (<150 ∼m) than the mechanical seeder dust, which contained a greater volume of larger particles (>1000 ∼m) than pneumatic seeder dust. Compared to the pneumatic seeder, the mechanical seeder showed lower drift values. With both seeders, the drift depositions decreased with increasing distance from the sowing area but no clear relationship between dust drift and wind speed could be found. CONCLUSION:The gathered physicochemical and drift data for wheat seed drilling extend the current dust drift database, and help to better understand the complex dust drift phenomenon. These data will serve as input to refine and validate a CFD dust drift model. Such a model will allow a better and quicker assessment of different scenarios (e.g. varying wind speeds and direction, treatment, drilling technique) at a lower cost than conducting more field trials.