Loss of herbicides from ground sprayers

Combellack, J. H.

doi:10.1111/j.1365-3180.1982.tb00164.x

Cited by 30 publications

(22 citation statements)

References 63 publications

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“…It shows that when conventional nozzles were used, wind speed parameters had a far greater impact than when air induction nozzles (TVI) were used (Figure 13a). This confirms that the size of the particles has a large impact on the off-target drift and is more important than the wind speed during spray drift generation process [110][111][112]. …”

Section: Overview Resultssupporting

confidence: 55%

Ground Deposition and Airborne Spray Drift Assessment in Vineyard and Orchard: The Influence of Environmental Variables and Sprayer Settings

et al. 2017

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Spray drift assessment encompasses classification of the capacity of each sprayer/ technology/setting combination to reduce or avoid the spray drift risk, as well as drift measurement to define buffer zones mandated during pesticide application. Compounding the challenge of these tasks is the great variability of field evaluation results from environmental conditions, spray application technology, canopy structure, and measurement procedures. This study, performed in Spanish context, evaluates the effects of different parameters on comparative measurements of ground and airborne spray drift employing the ISO22866:2005 protocol. Four configurations of air blast sprayers, derived from two fan airflow rates and two nozzle types (conventional and air-induction), were tested in orchard and vineyard at late growth stage. Spray drift curves were obtained, from which corresponding Drift Values (DVs) were calculated using an approximation of definite integral. Both sprayer settings and environmental variables statistically affect spray drift total amounts and result variability. PCA analysis showed that nozzle type and wind speed characteristics explained 51% and 24% of the variance, respectively. In particular, mean wind direction influence ground sediments (Pr < 0.01) and maximum wind speed strongly influence airborne drift value (Pr < 0.0001). The wind characteristics concealed the influence of adopted fan airflow rates on final spray drift assessment results. The effect of uncontrollable environmental conditions makes objective and comparative tests difficult.

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Section: Overview Resultssupporting

confidence: 55%

Ground Deposition and Airborne Spray Drift Assessment in Vineyard and Orchard: The Influence of Environmental Variables and Sprayer Settings

et al. 2017

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“…In particular, the absence of different DSD PC values for the various configurations tested might be attributable to the small amount of liquid sprayed (single alley sprayed using just one side of the sprayer) during calm wind conditions that counteracted the proven spray drift differences usually associated with nozzle type . Normally, increased wind speed enhances the drift reductions of air induction nozzles because large particle size impacts off‐target drift more in windy conditions and therefore plays a strong role during spray drift generation . On the other hand, DPV AC (Fig.…”

Section: Discussionmentioning

confidence: 99%

Toward a new method to classify the airblast sprayers according to their potential drift reduction: comparison of direct and new indirect measurement methods

Grella

Marucco

Balsari

2019

Pest Management Science

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BACKGROUND: Drift is one of the most important issues to consider for realising sustainable pesticide sprays. This study proposes an alternative indirect methodology for comparative measurements of drift reduction potential (DRP) generated by airblast sprayers, aimed at overcoming the practical inconveniences and drawbacks of standardized ISO 22866:2005. A test bench in the absence of target crop and wind was employed to measure drift potential values (DPVs). A variation to the proposed method that introduced a crop between sprayer and test bench device was considered to study the canopy effect (absence/presence) and to validate the method. In parallel, direct spray drift measurements (ISO 22866) were performed to obtain the drift value (DV). A representative vineyard airblast sprayer was evaluated in four configurations (a combination of two fan airflow rates and two nozzle types). The configurations tested under the three methods (direct and indirects) were classified according to achieved drift reduction percentages (ISO 22369-1:2013) and compared. RESULTS: Indirect methods discriminated DPVs from different nozzles (conventional, air induction) and fan airflow rate (high, low) combinations.Indirect methods also showed that despite crop influence on drift amount, target absence has a negligible effect when used specifically for DRP determination/classification. In fact, identical DRP final classifications were achieved for the two methodologies tested. Alternatively, all tested configurations resulted in lower DR values following the ISO 22866 field method, which caused different final classifications due to the high dependence of results on external factors. CONCLUSIONS:The alternative test bench methodology, characterized by the absence of target crop and calm of wind, was considered feasible for comparative measurements of airblast sprayer DRP.

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“…Among the technical factors that affect spray drift, the size of the particles has a large impact on the off-target drift (Take et al, 1996), as this parameter has been found to be more important than the environmental wind speed during the spray drift generation process (Bird et al, 1996;Combellack, 1982;Frost and Ware, 1970;Grella et al, 2017). Thus, producing a fine spray tends to increase the drift risk (Bode et al, 1976).…”

Section: Introductionmentioning

confidence: 99%

Developing strategies to reduce spray drift in pneumatic spraying in vineyards: Assessment of the parameters affecting droplet size in pneumatic spraying

Miranda‐Fuentes

Marucco

González-Sánchez

et al. 2018

Science of The Total Environment

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Pneumatic sprayers are widely used in vineyards due to their very fine droplet size, which makes the drift risk to become an important problem to be considered. The aim of this study was to assess the effect of the spout diameter at the release point on the spray droplet size and uniformity achieved for different liquid flow rates (LFR) and air flow rates (AFR). A test bench was developed to simulate a real pneumatic sprayer under laboratory conditions, and it was empirically adjusted to match the air pressure conditions as closely as possible to real working conditions. Two positions of insertion of the liquid hose, the conventional position (CP) and an alternative position (AP), were tested for three LFRs, 1.00, 1.64, and 2.67Lmin, and four AFRs, 0.280, 0.312, 0.345, and 0.376ms. The air speed decrease between the two insertion points of the liquid hose was measured. A Malvern SprayTec® instrument was used to measure the droplet size, and the D50, D10, and D90 parameter values were obtained. The relative SPAN factor (RSF) was also calculated. A model to predict variations in D50 was fitted using the aforementioned parameters. The results show that variations in the diameter of the spout significantly change the droplet size, producing a mean increase of 59.45% in D50 and similar increases in D10 and D90. The model developed to predict variations in D50 has a very high degree of accuracy (R=0.945). The relative decrease in the air speed along the spout did not present significant differences for the different airflow rates tested. The results of the study show that the droplet size produced in pneumatic spraying can be modified easily by varying the air spout dimensions. This should be taken into account by manufacturers from a design point of view.

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Loss of herbicides from ground sprayers

Cited by 30 publications

References 63 publications

Ground Deposition and Airborne Spray Drift Assessment in Vineyard and Orchard: The Influence of Environmental Variables and Sprayer Settings

Ground Deposition and Airborne Spray Drift Assessment in Vineyard and Orchard: The Influence of Environmental Variables and Sprayer Settings

Toward a new method to classify the airblast sprayers according to their potential drift reduction: comparison of direct and new indirect measurement methods

Developing strategies to reduce spray drift in pneumatic spraying in vineyards: Assessment of the parameters affecting droplet size in pneumatic spraying

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