Experimental evaluation of UAV spraying for peach trees of different shapes: Effects of operational parameters on droplet distribution

Yanhua Meng, Jinya Su, Jianli Song*, Wen Hua Chen, Yubin Lan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)


Small-scale plant protection Unmanned Aerial Vehicles (UAVs) are finding a wide range of appli cations in modern agriculture management (including aerial spraying) due to their high efficiency and flexibility, low labour/water requirement and no damage to crops and soils, which substantially increase agricultural productivity and sustainability. UAV operational parameters, however, have remarkable effects on droplet distribution in UAV spraying, which significantly affect pesticide utilization rate and treatment effectiveness. Therefore, this work aimed to evaluate the effects of UAV operational parameters on droplet distribution for orchard trees. In particular, peach, an important orchard tree worldwide, is investigated in this study, and two typical tree shapes were considered including Y-shape and Central Leader (CL)-shape. Specifically, UAV spraying experiments were performed in Shandong Institute of Pomology, Shandong Province, China, and gas powered helicopter 3WQF120-12 was chosen as the spraying platform. The UAV operational parameters under consideration include flight route (intra-row, inter-row), flight velocity (four levels: 2, 3, 4, 5 m/s), number of spray times (1 vs 2) and nozzle flow rate. Droplet coverage rate at different positions and layers, obtained by water sensitive papers, was chosen as the metric to evaluate spraying performance. Experimental results show that: (1) the spraying uniformity is different between Y-shape and CL-shape peach tree, where Y-shape exhibits uniformity for positions at inner or outer layers. CL-shape results in a higher droplet coverage at top layer while with uniformity at lower three layers; (2) for Y-shape peach, intra-row route obtained a higher droplet coverage rate; while for CL-shape peach inter-row not only saved spraying volume but also results in a higher droplet coverage rate; (3) for both tree shapes, the increase in flight velocity (2–5 m/s) significantly decreased the droplet coverage rate; (4)for Y-shape peach with doubling the number of spraying times decreased the spraying performance for unit area.(5) for CL-shape peach with intra-row route, increasing the nozzle flow rate from 1.8 to 2.2 L·min-1 can significantly improve the droplet coverage rate at top and bottom two layers. It is envisioned that this study can provide some fundamental guidance of the operation of small UAVs for the aerial spraying of peach trees and similar orchards.

Original languageEnglish
Article number105282
Number of pages12
JournalComputers and Electronics in Agriculture
Early online date15 Feb 2020
Publication statusPublished - Mar 2020

Bibliographical note

Funding Information:
Yanhua Meng, Jianli Song and Yubin Lan are supported by National Key Research and Development Program of China (2017YFE0122400), the National Key Research and Development Plan Program of China (2016YFD0200700), the Leading Talents of Guangdong Province Program (2016LJ06G689), Science and Technology Planning Project of Guangdong Province (2017B010117010). The 111 Project (D18019). Jinya Su and Wen-Hua Chen are supported by the UK-China Agritech Challenge?Utilizing Earth Observation and UAV Technologies to Deliver Pest and Disease Products and Services to End Users in China (BBSRC with Grant No. BB/S020977/1).

Publisher Copyright:
© 2020 Elsevier B.V.


  • Droplet coverage
  • Operational parameters
  • Peach trees
  • Plant protection
  • Unmanned Aerial Vehicle (UAV)


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