Edge of field variation of spray drift deposition

Spray drift experiments were performed to quantify the variation of spray drift deposition alongside the treated field. A comparison is made between the standard setup of a spray drift measurement measuring spray drift deposition in the middle downwind of the edge of the sprayed field. Ground collectors are used in the area 0.50–15 m from the last nozzle and a continuous line of ground collectors at 2 m and 5 m from the last nozzle alongside the total length of the crop-edge of the field. A potato field of 102 m length and 75 m width edges was therefore sprayed. During spray application wind speed and direction was recorded. The spray liquid used was tap water with fluorescent dye added Brilliant Sulfo Flavine) and a non-ionic surfactant (Agral Gold). In the laboratory, the BSF was extracted from the collectors with demineralised water and analysed by fluorimetry (Perkin Elmer LS 45). Spray deposits were expressed as μL cm-2 and as percentage of the applied spray volume. During spraying the sprayer boom movement was measured in the horizontal plane and vertical plane. Spray drift deposition pattern alongside the field edge was compared to the standard spray drift setup and the sprayer boom movement.