Enhancing spray deposition in grape canopies through the development of new prototype air-disturbance sprayers

To address the challenge of uneven and inadequate deposition within the canopy and on the lower side of the leaves in vineyards spraying operations, the performance of new prototype air-disturbance sprayers was evaluated. Firstly, the optimal parameter combination under the swing type disturbance mode (SW) was determined through orthogonal analysis. Then, a multivariate variance analysis was employed to compare the performance indicators of SW with those found under the rotating type disturbance modes (anticlockwise rotating AR, and clockwise rotating CR), as well as with the blank control group. It has been confirmed that SW could increase the penetration of droplets within the canopy and obtain the optimal deposition uniformity (58.72%). This mode did not affect the canopy deposition, but it decreased the coverage of droplets on the lower side of the leaves (11.82%). AR achieved a deposition uniformity of 62.06% and could consistently ensure that the coverage of both sides of the leaf was over the threshold of 30%. However, it decreased the canopy deposition. Generally speaking, CR not only significantly increased the canopy deposition, but also improved the deposition uniformity to 60.94% (second only to SW). Although the coverage on the lower side of the leaf for CR (25.41%) has not yet reached the threshold requirement of 30%, it could be anticipated that the implementation of two-sided spraying could effectively solve this deficiency. Therefore, the future positioning of a clockwise rotating turbulence system at the airflow outlet of the air-assisted sprayer will be a valuable choice.