Effect of differences in international reference technique and evaluation zone on the classification of spray drift reducing techniques

A series of spray drift experiments were conducted to classify a specific spray technique for the Netherlands, the United Kingdom and France. The candidate spray technique was equipped with three different nozzle types; a standard flat fan, a 50% and a 90% drift reducing nozzle type. In order to classify the sprayer for the spray drift reduction classification system in the Netherlands and the UK the reference spray technique used was a boom sprayer operating at 50 cm boom height, 50 cm nozzle spacing at 6.5 km h-1 forward speed and equipped with Tee Jet XR11004 flat fan nozzles operated at 3 bar spray pressure. For the French system, the reference spray technique was a boom sprayer operating at 70 cm boom height, at 8 km h1 forward speed and equipped with TeeJet XR11002 flat fan nozzles operated at 2.5 bar spray pressure. The classification against different reference spray techniques and evaluation zones (2-3 m; 2-6 m; 5 m) is presented for three candidate spray techniques based on comparative spray drift experiments under similar crop and weather conditions. Similarities and differences between the classifications following the different systems are highlighted. Results show a basis for the exchangeability of the classification of spray drift reducing techniques between the different classification systems based on field data and the potential for further harmonisation of certification procedures between countries