Onderzoek aan spuitdoppen Teejet AI 80015VS en AI 8002VS voor classificatie op basis van driftgevoeligheid

In this study nozzle type Teejet AI 80015VS and AI 8002VS were investigated to establish their drift reduction classification for both downward and upward and sideways application techniques. For downward applications, drop size distributions and drop speeds were measured, which were fed into the IDEFICS spray drift model. Various sprayer boom setups were tested by varying sprayer boom height and inter-nozzle distance. These configurations were tested first on a patternator to evaluate the evenness of the spray liquid distribution, by quantifying the coefficient of variation (VC) and selecting the situations where VC<10%. Subsequently, drift simulations were carried out and drift reductions were determined with respect to a reference spray application. Finally, the configurations were classified regarding their drift reducing capabilities. Currently, the Dutch classification system is for boom heights of 0.50 m only, while the outer nozzle should be positioned at 0.50 m inside the crop edge. Respecting these conditions, for the investigated situations the nozzle type AI 80015VS would be classified as DRN75 at liquid pressure of 200 kPa and a nozzle distance of 0.50 m; at 500 kPa liquid pressure a DRN50 classification would be possible. At nozzle distance of 0.25 m the nozzle type AI 80015VS would reach DRN75 at 200 and 300 kPa liquid pressure, while at 500 kPa liquid pressure the reduction class would be DRN50. The other nozzle type, AI 8002VS, would yield the DRN75 class at nozzle distance of 0.50 m and 500 kPa liquid pressure. At 0.25 m nozzle spacing the DRN90 reduction class is within reach at 200 kPa liquid pressure, while at 300 and 500 kPa this would be DRN75. At lower boom height higher reductions are possible; however, such situations are not covered by the current Dutch classification system. Nozzle classification for upward and sideways application techniques only depends on the volume fraction of smaller drops (V100). Measured values of V100 were compared with those of boundary nozzles from the nozzle classification for spray application in fruit orchards. This resulted in the following classification suggestions. Nozzle type AI 80015VS would be classified as DRN90 at 200 and 300 kPa liquid pressure and as DRN75 at 500 kPa liquid pressure. For nozzle type AI 8002VS the reduction class DRN95 would be appropriate at a liquid pressure of 200 kPa; at 300 kPa liquid pressure the class DRN90 would fit while at 500 kPa class DRN75 would be appropriate.