Spray drift measurements to evaluate the Belgian drift mitigation measures in field crops

Germany, England, the Netherlands and Sweden have adopted measures to reduce the pollution of surface waters by spray drift in field crops and orchards. In 2004, Belgium also adopted a drift mitigation strategy. The Belgian legislation mainly consists of a classification list of spray nozzles; air assistance and shielded systems are also considered. The nozzle list firstly is an integration of the classification work of Germany, England and the Netherlands; it uses the most stringent of these three classifications. In this research, drift experiments examined whether the existing mitigation measures in field crops can be validated, and also whether the existing measures can be expanded with other techniques that are known to be drift-reducing but are not yet a part of the measures. The results were also compared with the legislations of other European countries. Spray drift was measured over grassland according to the international standard ISO/FDIS 22866. A Hardi Commander Twin Force field sprayer with boom length 27m, nozzle spacing 0.5m, and tank volume 32001 was used. Both conventional spraying and other spraying techniques were evaluated. Conventional spraying was defined as a spray boom with height 0.5 m, no downward air assistance, flat fan Hardi nozzles ISO 110 03, spray pressure 0.3 MPa, and forward driving speed of the tractor 8 kin h(-1). The other (non-reference) applications were varying nozzles (type and size), spray pressure, forward driving speed, boom height and applying downward air assistance. It was considered that the current Belgian measures can be improved and expanded. (C) 2007 Elsevier Ltd. All rights reserved.