Emission reduction in orchards by improved spray deposition and increased spray drift reduction of multiple row sprayers

摘要

The use of multiple row orchard sprayers is increasing in the Netherlands. These type of sprayers reduce labour costs and improve pest and disease control. The latter because less time is needed to spray an orchard compared to standard axial fan and cross flow fan sprayers. Timeliness is higher and anticipation to weather conditions and disease development improves when using multiple row sprayers. It is assumed that multiple row sprayers could reduce spray drift significantly. This is due to the spraying system that sprays tree rows from both sides at the same time, in contrast to standard orchard sprayers that spray the tree row only from one side. In a series of experiments a comparison was made between the standard cross flow orchard sprayer (Munckhof) and a three row sprayer (KWH). Several nozzle types and settings for air assistance were included in the experimental set up. The spray drift measurements were conducted in the dormant leaf stage and in the full leaf stage of the apple trees. From the experiments, it could be concluded that in the dormant stage spray drift reduction of the KWH three row orchard sprayer equipped with Albuz ATR Lilac nozzles was 50% when compared to the Munckhof cross-flow fan sprayer equipped with the same nozzleand spray pressure and a 3 m crop-free buffer zone. Spray drift reduction increased to 81% in the full leaf stage. The KWH three row orchard sprayer equipped with the Albuz TV1 80015 venturi nozzle resulted in spray drift reductions of 91% in the dormant and 98.6% in the full leaf stage. Using the three row KWH variable air assistance system (VLOS) in combination with the TVI80015 nozzles resulted in a spray drift reduction of 96% in the dormant and 95% in the full leaf stage. Similar effects were found for airborne spray drift. It is therefore advised to setup additional spray drift reduction classes of 97.5% and 99% in the spray drift reduction classification system. Further research is needed to assess spray deposition in the tree canopy and biological efficacy of multiple row orchard sprayers.