## 4 Discussion  
The study results indicate that the SSCDS configured modified irrigation micro-emitters resulted in comparable canopy deposition and coverage against that of hollow cone nozzles. The modified irrigation micro-emitter configured treatment resulted in 28.0%  
Figure 9: Mean aerial deposition observed at (**a**) 3 m and 6 m downwind and (**b**) 3.3 m, 3.6 m and 3.9 m above ground level for tested SSCDS treatments (i.e., T1 and T2). Different lowercase letters above individual bar plots indicate the differences (significant or not significant) in transformed mean at \(\alpha\) = 0.05 and associated error bars indicate standard error; presented values are non-transformed mean ground deposition (ng cm\({}^{-2}\)). \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Off-Target Loss**} & \multirow{2}{*}{**Treatment**} & **Deposition (ng cm\({}^{-2}\)) \({}^{*}\)** \\  & & **[Aerial Drift (\%)] \({}^{\#}\)** \\ \hline \multirow{3}{*}{Aerial drift} & T1 & 0.7 \(\pm\) 0.1 \({}^{\text{b}}\) \\  & & [0.02] \\ \cline{2-3}  & & 3.2 \(\pm\) 0.4 \({}^{\text{a}}\) \\ \cline{2-3}  & T2 & [0.08] \\ \hline \hline \end{tabular} \({}^{*}\)Transformed data was used for statistical analysis; presented data are non-transformed values in (mean \(\pm\) SEM) format; different lowercase and uppercase letters represent the differences (significant or not significant) in transformed mean at \(\alpha\) = 0.05; \({}^{\#}\) The values in the square bracket represent the percent of applied active ingredient drifted into the air; The lowercase and uppercase letters in superscript indicates the significant differences in transformed mean at \(\alpha\) = 0.05.  
\end{table} 
Table 8: Mean aerial drift losses evaluated for tested treatments. and 19.5% higher mean spray deposition and coverage, respectively, compared to hollow cone nozzle configured SSCDS treatment. Despite a considerable numerical difference in deposition and coverage between the modified irrigation micro-emitter and hollow cone nozzle SSCDS treatment, the corresponding difference was statistically non-significant, perhaps due to high variability in deposition and coverage data and a relatively small number of samples. Such variability is very typical in agrochemical application scenarios [20,31,32] and could be reduced by increasing the number of replicates in the experiment. The bottom zone deposition and coverage for both the tested treatments were highest compared to the other sampling zones. The spray droplets that missed the target and spray run-off from the top and mid canopy zone, settled to the bottom, would have resulted in a higher deposition in later zone. The modified irrigation micro-emitter treatment resulted in 59.4% and 33.1% higher bottom zone deposition and coverage, respectively, compared to the hollow cone nozzle treatment. Similarly, mid zone deposition and coverage was higher than the hollow cone nozzle treatment. Micro-emitter modification also improved the leaf surface deposition and coverage. The abaxial and adaxial deposition of modified irrigation micro-emitter treatment were 38% and 21.6% higher than hollow cone nozzle treatment, respectively. Likewise, the modified treatment had 38.3% and 12.4% higher abaxial and adaxial coverage compared to hollow cone nozzle treatments. Additionally, modified SSCDS treatment resulted in lower CV in spray deposition and coverage between the abaxial and adaxial leaf surfaces. Results indicate that the micro-emitter modification also augmented the leaf level spray uniformity. Previous SSCDS configuration test studies have reported that shower down arrangement with only one nozzle/micro-emitter atop tree canopy was the simplest and the most economical SSCDS configuration [20,22]. However, poor bottom zone and abaxial leaf surface deposition were perceived as a major constraint with such configuration [33]. The presented 3-tier configured SSCDS with modified emitters indicates a substantial increase in the bottom zone and abaxial leaf surface deposition and coverage.