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

Abstract

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.

Comprehensive assessment of intelligent unmanned vehicle techniques in pesticide application: A case study in pear orchard

“…This result indicated that UAV application technology is unstable, which could affect the overall pest control in the orchards. Generally, it could achieve pest control effects when the deposit coverage exceeds 1% during UAV application ( Wang et al, 2022 ) due to its high-concentration spraying property. The results indicated that UAV application could adapt to orchard pest control.…”

“…The former method has been recognized as a high-efficiency pesticide application technology and is widely used for pest control in orchards ( Li et al, 2022 ). However, it is only suitable in standardized orchards with fixed wide spacing and relatively flat pavement ( Wang et al, 2022 ). Human spray guns can make up for this shortcoming.…”

“…It has a major advantage in low labor demand, which is important for orchard management in the future. Moreover, intelligent equipment can also ignore terrain obstacles and planting patterns, which is important for orchards in hilly areas and disorderly planting orchards, such as orchards in southwestern China ( Wang et al, 2022 ). Some intelligent equipment has the ability to work at night, which can significantly improve working efficiency.…”

Characteristics of unmanned aerial spraying systems and related spray drift: A review

“…Spraying with UASS has proven to be feasible in the prevention and control of crop diseases and pests by spraying insecticides or fungicides ( Meng et al, 2018 ; Yan et al, 2022 ). In the case of trees grown on steep slopes, the quality of the application is partially limited by the flight altitude of the sensor and terrain following technology with the help of lidar for example ( Meng et al, 2022b ; Wang C. et al, 2022 ). Moreover, a denser crop canopy also presents limitations in terms of droplet penetration ( Chen et al, 2020b ; Yu et al, 2022 ).…”

Design and development of orchard autonomous navigation spray system

“…Exploring an automatic sprayer with a high degree of automation and a high pesticide utilization is a hot spot for agricultural machinists. There are mainly two thorny problems in the development of automated orchard sprayers: one is to achieve efficient penetration of pesticides in a low dense canopy and reduce the loss of chemical solution ( Meng et al, 2022 ; Wang C. et al, 2022 ), while the other is to let the machine traverse the orchard autonomously without manual control in the orchard with a closed canopy and blocked vision ( Bergerman et al, 2015 ; Ye et al, 2018 ; Zhang et al, 2020 ). Considerable research has been conducted on the above two issues.…”