Assessment of spray deposition, drift and mass balance from unmanned aerial vehicle sprayer using an artificial vineyard

Changling Wang; Andreas Herbst; Aijun Zeng; Supakorn Wongsuk; Baiyu Qiao; Peng Qi; Jane Bonds; Verena Overbeck; Yi Yang; Wanlin Gao; Xiongkui He

doi:10.1016/j.scitotenv.2021.146181

Assessment of spray deposition, drift and mass balance from unmanned aerial vehicle sprayer using an artificial vineyard

Sci Total Environ. 2021 Jul 10:777:146181. doi: 10.1016/j.scitotenv.2021.146181. Epub 2021 Mar 3.

Authors

Changling Wang¹, Andreas Herbst², Aijun Zeng³, Supakorn Wongsuk³, Baiyu Qiao³, Peng Qi³, Jane Bonds⁴, Verena Overbeck², Yi Yang⁵, Wanlin Gao⁶, Xiongkui He⁷

Affiliations

¹ Centre for Chemicals Application Technology, China Agricultural University, Beijing 100193, China; College of Information and Electrical Engineering, China Agricultural University, Beijing 100094, China.
² Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Application Techniques in Plant Protection, 38104 Braunschweig, Germany.
³ Centre for Chemicals Application Technology, China Agricultural University, Beijing 100193, China; College of Science, China Agricultural University, Beijing 100193, China.
⁴ Bonds Consulting Group LLC, Panama City 32408, USA.
⁵ Beijing TT Aviation Technology Co. Ltd, Beijing 102202, China.
⁶ College of Information and Electrical Engineering, China Agricultural University, Beijing 100094, China.
⁷ Centre for Chemicals Application Technology, China Agricultural University, Beijing 100193, China; College of Science, China Agricultural University, Beijing 100193, China. Electronic address: xiongkui@cau.edu.cn.

PMID: 33689892
DOI: 10.1016/j.scitotenv.2021.146181

Abstract

Under the rapid development of unmanned aerial vehicle (UAV) plant protection products (PPP) application in Asian countries, the drift risk of UAV sprayer operation in orchard or vineyard is fairly high because of the much finer droplets generated and the higher height than ground sprayers, increasing threats to non-targeted crop, human and environment. However, there is few of comprehensive experimental study on the effects of UAV type and nozzle type on spray deposition and drift from UAV sprayer. The objectives of this study were to compare the spray performance of three different typical commercial UAV types (helicopter, 6-rotor and 8-rotor) with two nozzles types (hollow cone nozzle, HCN and air-injector flat fan nozzle, AIN) in vineyard. An artificial vineyard and three vertical collection frames, designed and built by ourselves, were applied for collecting droplets together with PVC collectors, petri dishes and rotary samples. The characteristics of deposition, drift and mass balance of UAV aerial spraying in vineyard were analyzed. As a result, under the crosswind speed of 3.11-3.79 m/s, AIN promoted spray deposition and uniformity and reduced drift significantly compared to HCN for all tested UAVs, improving of the utilization of PPP. The fitted regression functions of the sedimenting and airborne drift were obtained, respectively, and the drift percentage reduction values of AIN compared to HCN determined based on those functions varied from 81% to 95%. With HCN, 49.3%-73.4% of measured droplets drifted into non-targeted area and the highest proportion of drift loss was found for the airborne spray drift. According to the principle of more deposition and less drift, the spray performance of the three UAVs can be ranked in an order of 6-rotor, 8-rotor and helicopter, and two main reasons causing the difference in spray performance were the vortex airflow and the nozzle arrangement.

Keywords: Airborne drift; Deposition; Droplet; Sedimenting drift; Sprayer; Unmanned aerial vehicle.