## 3 Results and Discussion
### Cumulative Sprayed Volume Curves and Their Classification According to ASAE S572.1  
The cumulative sprayed volume curves, obtained with cannon (Figure 8) and hand-type (Figure 9) nozzles by testing all configurations (combination of HP, LFR and AS), compared with the American Society of Agricultural and Biological Engineers (ASABE) nozzles classifications (ASABE S572.1) [63], showed that an appropriate selection of pneumatic sprayer operational parameters, namely LFR and AS, led to a limited change in the spray quality generated, varying from very fine (VF) to fine (F) in the best cases. On the contrary, changing HP deeply affected the spray quality and reached the coarse (C) (Figure 8) and very coarse (VC) (Figure 9) spray quality when the liquid hose was tested in the extreme position (XP) combined with reduced AS, irrespective of LFR. Even if [PERSON] et al. [53] recognize the importance of a proper selection of LFR and AS parameters in order to vary the spray quality in conventional pneumatic sprayers, likewise it was clear that the spray quality extent change from VF to F was not enough to guarantee environmental safeguard, despite the increased droplet size dimension. For this reason, according to the preliminary tests performed by [PERSON] et al. [55], the HP change along the pneumatic spouts is proven as the driving factor for changing the spray quality. This strategy allows to achieve a range of different spray qualities comparable to that reachable with hydraulic nozzles, which can be varied in type (conventional vs air induction) and size [43]. Thus, at the time of application, in both pneumatic nozzle types the selection of HP allowed to vary the spray quality in a wide range without changing the other operational parameters selected for the application (LFR and AS). In detail, the cumulative sprayed volume curves derived from the tested configurations using the liquid hose in conventional position (CP) showed a droplet spectrum similar to the hydraulic nozzles Albuz(r) ATR lilac used at 0.7 MPa (Figures 8 and 9) and selected as reference. Only the hand-type nozzle tested in CP position with AS of 59.7 and 64.6 m s\({}^{-1}\) showed a coarser spray quality, namely fine (F), irrespective of LFR (Figure 9). On the contrary, none of the tested configurations with both cannon- and hand-type pneumatic nozzles in XP position achieved the extra coarse (XC) spray quality, likewise that generated by the air-induction Albuz(r) TVI8001 nozzles (0.7 MPa pressure) used as reference nozzle for the coarse spray quality (Figures 8 and 9). In general, the liquid hose position in AP and OP allowed intermediate spray quality, varying from F to M according to the LFR and AS selected. Even when the hand-type nozzle generated averagely larger droplets than the cannon-type did, the spray quality produced by both of them, for the same tested configuration, was very similar (Figures 8 and 9). In practice, no substantial difference in prospective coverage of the leaves and fruits could be noticed between the two nozzle types. In any case, the possibility to vary in a wide range the droplet size by simply adjusting the liquid hose position gives, for the first time, the opportunity to both farmers and technicians to match the environmental requirements, balancing at the same time the treatment specifications for every spray application while using pneumatic spraying in vineyards. Recently, [PERSON] et al. [58] demonstrated through field trials that the variation in the spray quality over the range investigated (from CP to XP) did not affect the canopy coverage, while coarser sprays (liquid hose in AP and XP) produced greater deposits on the target. Concurrently, the use of cannon spout in XP position significantly reduced the off-field ground losses in the downwind area. Figure 8: Cumulate sprayed volume (%) curves as a function of droplet size (\(\upmu\)m) per liquid flow rate (LFR), airflow speed (AS) and liquid hose position (HP) for the cannon-type nozzle.