Using the results shown in Figure 3, we changed the
citrus plant shape from a round head shape to an open
center shape and got a lower LAI. These agronomic
measures were carried out to increasing the droplet
deposition density. Figure 4 shows the comparative
analysis results of droplets deposition density by UAV
spraying on the round head shape and the open center
shape crown. As a whole, the droplet deposition density
of the 1.0 m working height reached record levels.
From the specific perspectives, under the condition of the
three working heights, the maximum droplet deposition
density of round shape trees was 54.85 droplets/cm2, with
a minimum value of 5.58 droplets/cm2 and a range of
49.27. The maximum droplet deposition density of the
open center shape was 69.28 droplets/cm2, with a
minimum value of 19.46 droplets/cm2, and a range of
49.82. This means that an open center shape canopy can
improve the droplet deposition density in each layer of
the citrus crown to some extent, but it also has a large
discrete degree.
process, and the different levels of pruning contribute to
the large discrete degree of droplet deposition density and
non-uniform distribution. Perhaps some effective
measures, such as more optimal operating parameters and
mechanical pruning, rather than human pruning, could
reduce the unfavorable influence of these uncertain
factors. Mechanical pruning easily gets the same size
tree crown, which could minimize the artificial error[31,32].
It is also an effective method to reduce cost and labor
intensity in the orchard management process