Foliar deposition and coverage on young apple trees with PWM-controlled spray systems

Salcedo, Ramón; Zhu, Heping; Zhang, Zhi Hong; Wei, Zhiming; Chen, Liming; Özkan, Erdal; Falchieri, D.

doi:10.1016/j.compag.2020.105794

Cited by 52 publications

(28 citation statements)

References 75 publications

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“…1. The index was originally proposed by Chen et al (2013) and recently used by Salcedo et al (2020) considering only the upper leaf side, but was adjusted here to take into account the uniformity of spray coverage measured on both leaf sides. To further investigate the effect of FS and DC on the uniformity of spray coverage under real-field conditions, a two-way ANOVA was performed using I U as dependent variable.…”

Section: Discussionmentioning

confidence: 99%

“…2a). The proposed sampling strategy is broadly used to assess leaf coverage under real conditions during spray application field trials (Hołownicki et al, 2002;Rincón et al, 2020;Salcedo et al, 2020;Salyani et al, 2013). The two plots were sprayed consecutively using pure water, meaning that the sprayer started the spray application in plot L in the alley between rows 1 and 2, and continued the application in plot S without stopping, then the left side of row 1 and the right side of row 2 were sprayed in plot S only (Fig.…”

Section: Experimental Plot Layout and Sampling Systemmentioning

confidence: 99%

“…Conventional spray applications generally apply agrochemicals at a constant rate (l ha −1 ) throughout the field, irrespective of pest/disease presence, planting system, crop density or tree canopy characteristics, which contribute to a lower application efficiency. In vineyards, orchards and other fruit productions high variability within and between trees in foliage density, canopy shape and size, typically results in trees being over-or under-sprayed when using a constant rate application (Chen et al, 2019;Salcedo et al, 2020;Zhu et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…This technology has lead to promising results in reducing both chemical inputs and spray drift. For example, Salcedo et al (2020) reported more than 65% spray volume reduction with a laser-guided PWM-controlled variable rate air-blast orchard sprayer compared to a constant rate application with the same sprayer (by disabling the PWM control system) in two-year old apple trees, while still providing sufficient spray deposits and coverage for effective fungicide and insecticide applications (proposed by pesticide manufacturers) without over-application. Furthermore, in this study, it was proven that the use of PWM solenoid valves improved distribution uniformities of both spray deposition and coverage.…”

Section: Introductionmentioning

confidence: 99%

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Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

et al. 2021

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The pulse width modulation (PWM) spray system is the most advanced technology to obtain variable rate spray application without varying the operative sprayer parameters (e.g. spray pressure, nozzle size). According to the precision agriculture principles, PWM is the prime technology that allows to spray the required amount where needed without varying the droplet size spectra which benefits both the uniformity of spray quality and the spray drift reduction. However, some concerns related to the effect of on–off solenoid valves and the alternating on/off action of adjacent nozzles on final uneven spray coverage (SC) have arisen. Further evaluations of PWM systems used for spraying 3D crops under field conditions are welcomed. A tower-shaped airblast sprayer equipped with a PWM was tested in a vineyard. Twelve configurations, combining duty cycles (DC: 30, 50, 70, 100%) and forward speeds (FS: 4, 6, 8 km h−1), were tested. Two methodologies, namely field-standardized and real field conditions, were adopted to evaluate the effect of DC and FS on (1) SC variability (CV%) along both the sprayer travel direction and the vertical spray profile using long water sensitive papers (WSP), and (2) SC uniformity (IU, index value) within the canopy at different depths and heights, respectively. Furthermore, the SC (%) and deposit density (Nst, no stains cm−2), determined using short WSP, were used to evaluate the spray application performances taking into account the spray volumes applied. Under field-controlled conditions, the pulsing of the PWM system affects both the SC variability measured along the sprayer travel direction and along the vertical spray profile. In contrast, under real field conditions, the PWM system does not affect the uniformity of SC measured within the canopy. The relationship between SC and Nst allowed identification of the ranges of 200–250 and 300–370 l ha−1 as the most suitable spray volumes to be applied for insecticide and fungicide plant protection products, respectively.

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Section: Discussionmentioning

confidence: 99%

Section: Experimental Plot Layout and Sampling Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

et al. 2021

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“…The gripping and drilling device is controlled via the stepper motor controller. The sprayer [6] is controlled by the power switch N-Channel, when using a PWM signal it allows smooth switching of the supplied voltage and control of the sprayer pump [5].…”

Section: Choice Of Component Basementioning

confidence: 99%

Microprocessor control system for a robotic platform for automated care for agricultural crops

et al. 2020

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In this paper, the use of electronic components for automating the care of agricultural crops is studied. A microprocessor control system has been developed, components of a robotic platform have been selected to ensure stable operation of the complex in the field. This platform combines ease of use and high performance. At the moment, there are few analogous foreign complexes with similar characteristics, therefore, the considered robotic platform is a promising development.

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Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

Wang

Liu

Zhang

et al. 2022

Pest Management Science

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BACKGROUND: In the last decade, unmanned aerial vehicle (UAV) sprayers have been growing rapidly worldwide as a new method for pesticide application, especially in Asian countries. More and more manufacturers and service providers are currently aiming at UAV spraying operation for fruit trees with higher economic value. We evaluated the spray performance of an electric six-rotor UAV sprayer using an orchard operation mode (different application volumes and flight patterns) in a hilly apple orchard with small and sparse trees (SS) and a plain orchard with tall-spindle trees (TS).RESULTS: Application volume (APV) had a significant influence on the spray coverage parameters in both orchards, while flight pattern, intra-row, inter-row and verti-row, had a relatively limited influence at 60 0 and 85 7 L/ha. The UAV's downwash airflow produced a good spray penetration in the isolated SS trees, but not for the conjoined TS trees. It is better to fly along and above rows at 63.5 L/ha or higher for SS trees. The excessively low underside coverage is the main drawback of UAV orchard pesticide application and the underside droplet size was generally less than 200 ∼m.CONCLUSION: Spray performance is closely related to tree shape, planting pattern, UAV payload, application volume, spray droplet size and downwash airflow field. The results provide data support for the best operational practice development and the decision model for the application volume of UAV sprayer orchard operations. The underside spray performance requires further improvement by several effective measures.

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Foliar deposition and coverage on young apple trees with PWM-controlled spray systems

Cited by 52 publications

References 75 publications

Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

Microprocessor control system for a robotic platform for automated care for agricultural crops

Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

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