Spray Qualities Research Articles

Utility of Hooded Broadcast Sprayer in Reducing Herbicide Particle Drift in Cotton

Use of hooded sprayers to mitigate spray particle drift during pesticide applications in cotton has not been investigated. Therefore, experiments were conducted in cotton fields in 2021 and 2022 to compare particle drift of dicamba applied with open and hooded broadcast sprayers at six different spray qualities: Fine (F), Medium (M), Coarse (C), Very Coarse (VC), Extremely Coarse (EC), and Ultra Coarse (UC). A fluorescent tracer dye was mixed and applied with the dicamba solution to measure drift deposition at different downwind distances up to 105 m from the target area. Results showed particle drift for F and M spray qualities applied with a hooded sprayer were reduced up to 94% and 77%, respectively, out to 10 m downwind from the application area compared to the open boom sprayer. Hooded sprayer decreased particle drift for C and VC spray qualities as well but only for short distances downwind (≤ 5 m). Sprayer type did not affect the particle drift for EC and UC spray qualities and it was also significantly lower than other spray qualities across both sprayer types. From 20 to 60 m downwind, dicamba applications with hooded sprayer exhibited as much as 42% less drift than open boom sprayer applications regardless of the spray quality. These data suggested that hooded sprayers are effective in reducing particle drift in cotton and thus can be utilized as a viable spray drift management technique for herbicide applications in cotton.

Characteristics of Spray Applications with Drones in Brazil: Spraying System and Swath Width

The objective of this study was to evaluate operational parameters and swath width characteristics of drone's spray applications in Brazil, considering aspects such as height and uniformity of deposition. There were evaluated 32 configurations of applications of 7 agricultural spraying drones. The technical basis for data collection was the use of a semiautomated electronic system, which analyzes the deposition of droplets on a polyester string and informs the ideal swath width for each configuration of drone applications, considering the deposition's coefficient of variation (CV). The system, denominated IFD ® (Swath Width Inspection), is based on ASAE S386.2 2018 standard. Likewise, it was collected information about flight high and drone configurations. IFD ® was a practical method to evaluate swath width and uniformity of drone applications. The results allowed an average increase on swath width of 27% compared to the swath previously used by the remote pilots. The swatch width obtained by using coarse (C) and very coarse (VC) droplet spectrum categories was 4.3 m, for median (M) 5.1 m, and fine (F) and very fine (VF) 5.2 m. The higher coefficient of variation (CV) was obtained for coarse and very coarse spray qualities, 16,7%, followed by median 16%, and fine and very fines, 14.4%.

Effect of carrier volume and spray quality on glyphosate-resistant soybean response to sublethal dicamba exposure.

Field experiments were conducted across three sites in Mississippi in 2018 to evaluate carrier volume and spray quality effects on glyphosate-resistant soybean response to dicamba. Treatments consisted of dicamba (5.6 g a.e. ha-1 ) plus glyphosate (8.7 g a.e. ha-1 ) applied to soybean at R1 using 140, 105, 70, 35, 14, or 7 L ha-1 . Each carrier volume was applied with TT11002 and XR110015 nozzles which resulted in Fine and Coarse spray qualities, respectively. A colorimetric dye was included in spray solutions to quantify spray coverage of each treatment. Spray coverage decreased with carrier volume and ranged from 21% to 3%. Conversely, soybean injury increased as carrier volume decreased. Soybean height 14 days after treatment (DAT) was reduced 34% to 37% from carrier volumes of 70 to 140 L ha-1 ; however, carrier volumes of 14 and 7 L ha-1 resulted in 45% height reductions. By 28 DAT soybean height was similar among volumes of 35 to 140 L ha-1 (39% to 42% reduction); however, volumes of 14 and 7 L ha-1 resulted in 46% and 51% reductions, respectively. Grain yield was reduced 14% from treatment at 140 L ha-1 and reductions increased with decreased carrier volume to 41% loss at 7 L ha-1 . Averaged across carrier volumes, Fine and Coarse sprays caused 30% and 26% yield loss, respectively. These data suggest that carrier volume profoundly affects soybean response to dicamba. Therefore, soybean response to sublethal dicamba doses applied at a constant carrier volume may not reflect physical drift exposure. © 2021 Society of Chemical Industry.

Performance comparison of oxidizer injectors in a 1-kN paraffin-fueled hybrid rocket motor

To investigate the effects of oxidizer injection on the performance of hybrid rocket motors (HRMs), we have designed, manufactured and tested four types of injector: showerhead (SH), hollow-cone (HC), pressure-swirl (PSW) and vortex (VOR). This study is motivated by the fact that the experimental measurements of N2O/paraffin firings are poorly presented in the open literature. Besides few publications are dedicated to the characterization of novel types of injectors in hybrid rocket propulsion application such as HC, PSW, and VOR. It is advantageous that the study was conducted in the same motor configuration, with the advantage that it allowed to compare the performance of different types of injectors.This paper analyzes the influence of the oxidizer injector design on the main performance parameters, such as fuel regression rate, specific impulse and combustion efficiency. First, in order to observe injector spray qualities, a series of cold tests using liquid water and liquid nitrous oxide are carried out, providing a good understanding of the spray profiles. Then, the motor performance data is obtained by a series of firing tests using N2O as oxidizer and paraffin as fuel. Comparison of the various injectors data is made with the same average oxidizer mass flux and feeding pressure. The showerhead is used as a benchmark in this study. During this experimental analysis, the VOR injector exhibits the highest regression rate, followed by HC and SH. Because the assessment of the regression rate was not enough to explain all the effects of the injectors on the motor performance, firing tests of small-scale hybrid motor have been carried out. In terms of spray properties, the PSW exhibits significant differences compared with the other injectors; it generates the smallest Sauter Mean Diameter (SMD) in the formed spray and achieves good atomization. In spite of the fact that the PSW injector leads to the lowest regression rate, it provides good specific impulse, increases the oxidizer-to-fuel ratio (O/F), as well as a uniform and smooth consumption of the paraffin fuel grain. VOR leads to the highest specific impulse. In terms of stability, VOR, HC and SH injectors exhibit lower oscillations in the chamber pressure. Some observations are made on exhaust plume intensity developed during combustion, and in firing tests with SH a blow-out phenomenon occur often. Similarly to liquid engines, it is possible in hybrid motors to increase the global propulsive performance using alternative designs of the injection system.

Reducing Herbicide Particle Drift: Effect of Hooded Sprayer and Spray Quality

AbstractA field study was conducted in 2015 and 2016 to compare particle drift of glyphosate using a fluorescent tracer dye applied with hooded and open sprayers at four spray qualities (Fine [F], Medium [M], Very-Coarse [VC], and Ultra-Coarse [UC]). F and M spray qualities exhibited up to 86% and 56% less drift, respectively, out to 31 m downwind with the hooded sprayer than with the open sprayer. Conversely, VC and UC spray qualities were not affected by sprayer type out to 31 m downwind. From 43 to 104 m downwind, hooded sprayer applications exhibited approximately 50% less drift than open sprayer applications, regardless of spray quality. From 43 to 89 m downwind, F spray qualities, regardless of sprayer type, exhibited higher drift than all other spray qualities. These data indicate that hooded sprayers considerably reduce drift of all spray qualities at short distances downwind. Additionally, at longer distances downwind, both larger spray qualities and sprayer hoods reduced drift independently.

Assessing a novel smartphone application – SnapCard, compared to five imaging systems to quantify droplet deposition on artificial collectors

Previous work sought to compare the results from imaging software for characterising droplet coverage, but none exists examining these five software programs: Droplet Scan®, Swath Kit®, Deposit Scan, Image J, and Drop Vision®-Ag. Additionally, a freely available smartphone application (App), SnapCard was developed to provide an extension tool for in-field analysis of spray collectors, but nothing has been published regarding its comparison to other imaging software systems. The present study was conducted to compare five existing imaging software types against the new App, SnapCard. Six nozzles producing different spray qualities were selected to spray a water+Brilliant Blue Dye solution over two artificial collector types (water sensitive paper and Kromekote®). Each collector was assessed for percent coverage using the five imaging systems and SnapCard. Objectives of this study were: 1. To establish a baseline dataset using the sprayed cards and five commonly used imaging systems, and compare the coverage results from each. 2. Use the baseline data from Objective 1 as a measurement of precision to judge the results from SnapCard. 3. Make an assessment of SnapCard against the other imaging software type data in the study.Results showed that SnapCard has similar measured coverage means compared to other image analysis systems. For both collector types, SnapCard measured coverage within one standard deviation of the means across nozzle types. SnapCard is able to provide an immediate answer without expensive software or needing a laboratory to measure sprayed collector coverage with precise results, which further underscores its value. The other software types were not all similar for coverage, but the data followed the same trends for droplet size. Increasing the droplet size consistently decreased the coverage, across both collector types. Droplet Scan reported the highest coverage while Drop Vision-Ag and Swath Kit gave lower coverage values on water sensitive paper and Kromekote® collectors, respectively.

Assessing the deposition and canopy penetration of nozzles with different spray qualities in an oat (Avena sativa L.) canopy

Consistent spray coverage that is evenly distributed throughout the canopy is necessary to control pest populations that can negatively affect yield. As applicators are switching to Coarser spray quality nozzles to reduce risk and liability of pesticide spray drift, concerns about efficacy loss are growing. Previous research has indicated that small droplets are the most effective at penetrating through crop canopies, but newer nozzle technologies have improved the effectiveness of larger droplet or Coarser sprays. Research was conducted to assess the canopy penetration of nozzles that produce Coarse, Very-Coarse and Extremely-Coarse spray qualities compared to nozzles that produce Fine and Medium spray qualities. Kromekote collectors were positioned in four configurations in an oat (Avena sativa L.) var. ‘Yarran’ (AusWest Seeds, Forbes, NSW, Australia) crop to quantify the coverage and droplet number densities (droplets cm−2) across three application carrier volume rates: 50, 75 and 100 L ha−1. Applications were made in the field in 30 cm tall, tillering oats, with collectors arranged in a randomised complete block design with three replications. The entire study was repeated on the following day. Results showed that droplet number densities were inversely related to the droplet size produced by the nozzles, yet coverage was increased more by application volume rate than droplet size. Thus, both spray drift reduction and improved canopy penetration can be achieved with proper nozzle selection and operation parameters for the control of agronomic pests.

Influence of micrometeorological factors on pesticide loss to the air during vine spraying: Data analysis with statistical and fuzzy inference models

Upward spray losses over vines were assessed during a typical air-assisted application using a fluorescent tracer dye and PVC lines as samplers. Linear multiple regression and fuzzy logic inference models were used to evaluate the effects of micrometeorological conditions on pesticide application for two spray qualities (fine and very fine). For the fine spray application (volume median diameter [VMD] 134 μm), the significant variables for the multiple regression were wind speed, air temperature and wet bulb temperature depression, with a coefficient of determination of 0.70. For the very fine spray application (VMD 65 μm), atmospheric stability was also significant, with a coefficient of determination of 0.82. Spray losses were also predicted using fuzzy inference systems, and high coefficients of determination were obtained (R2=0.72 for the fine spray and 0.66 for the very fine spray). Interpretable rules were established for the characterisation of micrometeorological parameters using the two sprays. Both analysis tools can be combined with mathematical modelling in order to evaluate air pollution and spray drift from simplified field tests.

The Measurement of Spray Quality for Pan Coating Processes

In this study, we describe the use of an innovative imaging system to measure and control the effect of nozzle operating parameters on the characteristics of a spray. These characteristics, including spray pattern, droplet size distribution, and droplet velocity, define the quality of the spray. They can have significant impact on the efficiency of the pan coating process and the quality of the coat. Suspensions of different composition were used in this study, and the authors demonstrated that the spray characteristics can be controlled with this approach. The main conclusions from this study were: Spray characterization can be a powerful tool for exploring and establishing the design space of nozzles operation in the pan coating process. When scaling or transferring a spray coating process, the focus should be on maintaining consistent spray qualities rather than limiting nozzle operating parameters to a range. This approach embraces the FDA concept of process analytical technology (PAT) and design space (FDA, Guidance for industry PAT—A framework for innovative pharmaceutical development, manufacturing, and quality assurance, 2004) for science-based operation flexibility.

Comparing Greenhouse Handgun Delivery to Poinsettias by Spray Volume and Quality

Insecticide and fungicide labels often lack specific recommendations on the spray volume and spray droplet sizes that will provide the most efficacious pest management of ornamental pest problems. A greenhouse trial was established to determine differences in spray retention in a poinsettia canopy between single-nozzle, handgun applications made using three different spray volumes and three different spray qualities. For the same areas of the canopy, there were few differences in spray deposit between treatments. Canopy position was a significant factor in the amount of spray found on foliar and artificial targets. Higher deposits were measured in the fronts and upper areas of the canopy than the backs and lower areas of the canopy. There were no significant differences in recovery of fungicide from leaves between treatments. The high-volume application produced the highest deposits on artificial targets across all spray qualities. There were no significant differences in overall spray deposit between the low- and medium-volume treatments.

Spray deposits and losses in different sized apple trees from an axial fan orchard sprayer: 2. Effects of spray quality

Two field experiments compared spray deposits and losses from very fine (volume median diameter (VMD)=156 μm), fine (VMD=198 μm) and medium (VMD = 237 μm) quality spray applications to young dwarf, dwarf and semi-dwarf apple trees from an axial fan orchard sprayer fitted with hydraulic hollow cone nozzles. All other spray application variables were kept constant. In one experiment, the very fine quality treatment deposited slightly but significantly less spray on leaves than the other treatments but there were no significant differences in the other. The very fine spray quality treatment deposited significantly less on fruitlets in both experiments, but differences were small. The leaf-to-leaf and tree zone-to-tree zone distributions of deposits were not affected significantly by the spray quality. The percentage spray cover, estimated by image analyses, on water-sensitive papers fixed horizontally in the middle of the trees was not markedly affected by spray quality though values were variable. The very fine and fine spray qualities gave significantly greater grand mean percentages of spray drift than the medium spray quality treatment in one experiment, though differences were either not or only just statistically significant in the other. Drift was greatest in the small trees and least in the large trees, consistent with an inverse relationship with tree area density (TAD). The medium spray quality gave significantly smaller deposits on the ground sampling lines than the very fine and fine treatments. In conclusion, variation in spray quality over the range investigated did not greatly affect the amount or macro-distribution of spray deposits on apple trees from the axial fan sprayer. The coarser sprays gave slightly greater mean deposits and smaller spray losses and are preferable from these points of view. Further work is required to establish the effects of spray quality on the micro-distribution of deposits on the target. A coarser pattern of spray deposition on the plant surface could be less efficacious biologically for some pesticides. Therefore, evaluation of the effects of spray quality adjustment on biological efficacy is required.

The Effect of Boom Section and Nozzle Configuration on the Risk of Spray Drift

The effect of spray characteristics and boom section on spray drift produced by agricultural flat-fan nozzles has been investigated using wind-tunnel techniques. Variations in the effective spray plume porosity to an air stream were achieved by varying spray quality and varying nozzle spacing from 125 to 750 mm, in six steps. Three boom sections were used: astandard boom; a deep boom, for maximum air stream blockage, and a profile boom for reduced vertical dispersion. Wind speeds were varied from 1·0 and 3·0 m/s. Flow visualization techniques showed that the air stream pattern varied with plume porosity and mean air velocity. Measurements of airborne spray, 2 m downwind of the nozzles, showed that drift decreased as sprays changed in quality from fine to coarse using British Crop Protection Council scheme as expected. Maximum airborne drift occurred at a nozzle spacing of 500 mm with all spray qualities. Although the vertical profile of airborne drift was influenced by boom section, the magnitudes of difference between extremes of boom configuration were much less than changes due to nozzle characteristics. Variations in drift risk are characterized by the mean drift, mean drift moment and section moment, and could provide a mechanism for the assessment of various boom shapes and designs in combination with different nozzle conditions.

Experimental air-assisted spraying of young cereal plants under controlled conditions

Cereal plants grown in trays outdoors were sprayed indoors, at the four-leaf stage, with and without air assistance from a commercial air-curtain device fitted with an electrically driven cross-flow fan. Flat-fan hydraulic pressure nozzles producing very fine/fine and medium spray qualities were fitted to the air duct so that they and the air curtain could be directed either 45 degrees forwards or 45 degrees backwards, relative to the direction of travel, as well as vertically downwards. Spraying was done at 0.5, 1.0 and 2.0 m s −1 and fluorescein deposits were measured on the plants and soil for all combinations of the above factors (36 spray options), each replicated three times. Analysis of deposits measured by spectro-fluorimetry showed that fine-quality sprays produced larger plant deposits than medium-quality sprays and that angling the spray trajectory, especially 45 degrees forwards, also substantially increased deposition. Forward angling was superior to the backward trajectory. Air assistance further increased the amount of spray retained, and reduced deposits on the soil. An increase in plant deposits of ∼74% was recorded for finer sprays angled forwards with air assistance compared with a medium-quality spray applied vertically without air assistance at a spray speed of 2 m s −1. At the slowest spray speed (0.5 m s −1) both spray qualities angled forwards with air assistance increased deposition by ∼110% compared with a mean deposition increase of ∼75% without air assistance. Air assistance substantially reduced (∼70%) spray drift in a wind tunnel at a wind speed of 4 m s −1, but significantly increased the small amounts of drift measured in winds of 1.0 and 2.0 m s −1.