Evaluation on Application and Spraying Effect of Air-Assisted Sprayer in Apple Orchard with Dwarfing Rootstocks

The application and spraying effect of 3 WG-1200 A air-assisted sprayer in dwarfing rootstock apple orchard were evaluated by investigating the droplet density, coverage and volume median diameter(VMD) in different canopy layers(2.0, 1.5, 1.0 m) and five directions(east, south, west, north and middle) of apple trees. The results showed that the droplet density was 166.99 per square centimeter, the coverage was 48.23%, and the VMD was 138.63 μm. The droplet density in different canopy layers of the trees had consistent trend with the coverage. The droplet density and coverage in the upper and middle canopy(2.0 m and 1.5 m) had no significant difference, but they were both higher than those in the lower canopy, while the VMD in different canopy layers showed an opposite trend. The change trends of the coverage and VMD in the five directions were consistent, and the values in the middle and east were the highest, followed by the north, south and west, respectively. The results indicated that droplet characteristics of the 3 WG-1200 A air-assisted sprayer met the basic requirements for pest and pathogen control. This study provides a theoretical basis and data support for the application and improvement of orchard application equipments in dwarfing rootstock apple orchard.

Design and test of target-oriented profile modeling of unmanned aerial vehicle spraying

Unmanned aerial vehicles(UAVs)are a new frontier in specialized plant protection equipment,which will increasingly be utilized in modern sustainable agricultural applications.The use of UAVs retrofitted with new structures for spraying allows precision pesticide applications on fruit canopies,which have positive effects on pesticide reduction,along with fruit quality and production improvement.In this work,a precision toward-target device(BUAV)was established through profiling of fruit branch modeling,along with a quality analysis of the coverage in a pear orchard compared to a conventional multi-rotor UAV(CUAV).Coverage under different canopy sections and on both sides of leaves was evaluated using Polyvinyl Chloride card samplers.The results indicate that coverage of the BUAV was 0.98%and 1.41%on the abaxial of the lower leaves interior of the canopy,which was 2.38 and 3.14 times higher than that of the CUAV.The BUAV tended to increase coverage in the course-parallel direction,while both the course-parallel and vertical directions increased the deposition coverage on the abaxial side of the interior canopy leaves by 1.8 times and 2.1 times compared to the CUAV,respectively.Simultaneously,the BUAV increased the proportion of droplets deposited on the canopy and reduced ground loss.The BUAV can improve the distribution of the wind field within the canopy effectively and improve the droplet deposition on the reverse side of the interior bore blade.