Droplet size spectra classification categories in aerial application scenarios

Hewitt, Andrew

doi:10.1016/j.cropro.2008.03.010

Cited by 40 publications

(33 citation statements)

References 7 publications

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“…The observed spread values were very similar, ranging from 4% up to 30%, though all but the DV0.1 spread data for the 4015 were less than 15%, matching the 5%-18% reported by Womac [10] . The means and means difference testing results showed significant variation, and thus significant difference between the in DV0.1, DV0.5 and DV0.9 data across the individual nozzles within each nozzle type (Table 4- 9). Generally, the data falls as would be expected, based on previous works, and for most nozzle types, the mean falls near the median of the data.…”

Section: Resultssupporting

confidence: 63%

“…These standards, however, are not applicable to aerial application conditions as the high-speed air results in secondary breakup of the spray resulting in non-sensical reference data. To address the need for a similar system in evaluating aerial sprays, a series of nozzles and pressures were evaluated under high airspeed conditions that returned similar reference curves to the existing standards [9] . Based on these nozzles and operational settings, ASABE Standard S641 [10] was developed for use in aerial application droplet size classification efforts…”

Section: Introductionmentioning

confidence: 99%

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Establishing reference nozzles for classification of aerial application spray technologies

Fritz

Hoffmann²

2018

International Journal of Precision Agricultural Aviation

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Measurement of droplet size from agricultural spray nozzles can be highly variable and heavily influenced by measurement systems, methods and physical difference in measurement facilities. Past efforts have developed a series of nozzles and operational pressure pairings that are used to define relative droplet size classes across the wide range of sizes typical in agrochemical applications. Until recently, the developed classification standards were only application non-aerial spray technologies, as the paired nozzle and pressures used did not account for the secondary breakup resulting from high airspeed typical to agricultural aircraft. A new standard has addressed this issue, with dedicated nozzle/spray pressure pairs designed to generate similar classification boundaries to current standards while operating in high airspeed conditions. To support the application of this standard, multiple sets of dedicated droplet size matched nozzles were developed.

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Section: Resultssupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Establishing reference nozzles for classification of aerial application spray technologies

Fritz

Hoffmann²

2018

International Journal of Precision Agricultural Aviation

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“…In the USA, a Spray Drift Task Force was specially set up to assess the impact of aerial applications on spray drift and developed a classification system based on the original BCPC spray classification (Hewitt, 2008). In the USA, a Spray Drift Task Force was specially set up to assess the impact of aerial applications on spray drift and developed a classification system based on the original BCPC spray classification (Hewitt, 2008).…”

Section: Spray Nozzlesmentioning

confidence: 99%

Aerial application

2014

Pesticide Application Methods

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“…The spray solution can alter the droplet size classification as is evident with some nozzles in this study (Table 5). Values for the droplet size classifications were previously recorded in 2008 (Hewitt 2008), prior to the development of the current ASAE droplet size classification system, but they are still relevant for defining the curves for each size classification. Most of the nozzles in this study did not have that type of effect (Table 5), but this is worth noting as labels and best management practices increasingly support the use of specific droplet size classes for specific efficacy and / or spray drift management end-points.…”

Section: Resultsmentioning

confidence: 99%

“…Each treatment across all nozzles was applied at a pressure of 350 kPa, with the exception of the reference XRVS 11003 which was sprayed at 300 kPa (consistent with international DRT studies) (ISO 2006;2008;2010). Nozzles were operated at this selected pressure as it falls within the manufacturer's recommended pressure operating range for all nozzles.…”

Section: The Nozzles and Spray Solutionsmentioning

confidence: 99%

Towards the optimisation of Coarse sprays to reduce drift and improve efficacy in Australian cropping systems

Ferguson¹

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The optimisation of Coarse sprays for control of insects, weeds, and diseases in agriculture involves understanding how those technologies are classified and selected for use. Coarse sprays are the focus of this thesis, because Coarse is a spray size classification that balances adequate coverage, while reducing pesticide spray drift. Spray drift is detrimental, and by selecting coarser droplet sprays, spray drift can be minimised. The initial research study in this thesis sought to identify the repeatability of each nozzle type by randomly selecting five units to test consistency of droplet size measurements across nozzle type.The optimisation of Coarse sprays involves understanding differences that separate uniform technologies, especially when uniform nozzles of the same droplet size classification category are selected. When using plants and efficacy studies alone to quantify spray coverage, specific coverage values are difficult to determine. This consideration prompted studies with artificial collectors to quantify droplet coverage and provide the droplet distribution across the collector to help aid in technology selection. Results from these studies showed that nozzles which produced the same spray quality based on the droplet size distribution did not result in similar coverage across collector types. Nozzles that resulted in the highest coverage were further studied in the subsequent chapters.The optimisation of Coarse sprays involves understanding how sprays move within plant canopies. Consistent spray coverage that is evenly distributed throughout the canopy is necessary to control pest populations that negatively affect yield. As applicators are switching to coarser sprays to reduce risk and liability of pesticide spray drift, concerns about efficacy loss are increasing. Results showed that droplet number densities were inversely related to the droplet size produced by the nozzles, yet coverage was influenced more by application volume rate than droplet size.The optimisation of Coarse sprays involves ensuring that measurement methods and techniques are precise for the selection of the best technologies. A freely available smartphone application (app), SnapCard was developed to provide for in-field analysis of spray collectors. Results from this study showed consistent agreement between Image J and the new app, SnapCard, both of which were used consistently in this study. 3 The optimisation of Coarse sprays requires using novel techniques for characterising sprays, notably artificial collectors. The use of artificial collectors for spray characterisation is well accepted, but there is no literature to bridge the knowledge gap to understand how each major artificial collector type differs. Using all collector types (water sensitive paper, Kromekote ® and Mylar ® ) in tandem was useful to properly characterise the sprays, in addition to helping to quantify the differences between each collector type for coverage and droplet number density analyses.An optimal Coarse spray should not drift in ...

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Droplet size spectra classification categories in aerial application scenarios

Cited by 40 publications

References 7 publications

Establishing reference nozzles for classification of aerial application spray technologies

Establishing reference nozzles for classification of aerial application spray technologies

Aerial application

Towards the optimisation of Coarse sprays to reduce drift and improve efficacy in Australian cropping systems

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