Some performance aspects of downwind fallout collection targets used in the assessment of Low Drift Equipment and their potential to predict absolute ground based deposits

摘要

Drift fallout collectors that are described in protocols to classify or rale low drift spraying equipment such as agricultural hydraulic nozzles have been investigated. The objective of this work, being to evaluate the recommended target types, gaining data, which may then be used to measure or predict absolute fallout quantities rather than just relative changes- In this work, differing collector types were used to monitor fallout from traversing nozzles in the controlled conditions of a wind tunnel. Relative volumes of drifting spray being presented, 1.0 metre from the nozzle were found to match the anticipated values. A nozzle with a BCPC Fine spray quality produced more drift, than those with a Medium or Coarse spray quality, with higher wind speeds also increasing the amount of drift. However, there were differences between fallout values downwind that could be attributed to collector type and their location within the tunnel. The two sizes of Petri dish used did not follow the anticipated trends or volumes, but sheets of aluminium foil and centrally located chromatography paper appeared to offer results that were more consistent with previous data. The flat surface of the Chromatography paper, being able to sample every point without a breakfrom - if needed - under the nozzle, to the full length of the wind tunnel's virtual floor. This use may offer the dual assurance that all spray can or cannot be seen to be recoverable and the characteristics of the individual downwind fallout patterns/absolute volumes can be recorded. These downwind fallout patterns, not perhaps being predictable from low numbers of small, discrete sampling at a few representative locations.