## 4 Discussion  
The study area is situated in a Mediterranean climate zone, primarily falling into the Warm Mediterranean Climate 'Cas' classification. In this region, the seasons are marked by hot and dry summers followed by mild and wet winters. Precipitation is concentrated during the winter season, while it remains relatively low throughout the summer months [37]. Our investigation was carried out during summer 2023, characterized by persistent and unusually hot climate conditions. This summer ranked among the hottest recorded in recent years, deviating significantly from the typical climate patterns of this geographic area [38, 39, 40]. Against this backdrop, the total tomato production was greater for plants grown in full sunlight exposure and under both watering regimes, compared to that obtained from plants grown under the PV panels. Specifically, a 55.3% and a 32% increase in the number of tomatoes was observed between HW-Control and HW-PV panel groups, and between the LW-Control and LW-PV panel plots, respectively. The size of tomato fruits was greater in plants cultivated under shaded conditions compared to those grown in the open field under full sunlight. Specifically, the tomato fruit size in the HW-PV panel group was 37% larger than those produced in the HW-Control group, while the tomato fruit size in the LW-PV panel group was 28% higher than in the LW-Control group. Anyway, the weight of LW-PV panel tomatoes surpassed that of the HW-Control fruits by more than 17%. Thus, the higher quantity of tomato fruits produced in the control plot, characterized by sunlight exposure, is partially compensated by the reduced size of the fruits. This aligns with the SAS adaptation of the plant in the shade, as previous studies have demonstrated that under shaded conditions, plants tend to develop fewer flowers [27, 41]. Indeed, similar findings regarding tomato fruit production have been reported in other studies [42, 43]. However, this study highlights the importance of shade to guarantee tomato production, particularly in situations of water scarcity. Notably, the difference in tomato size was substantial. Thus, the difference in the total fruit fw harvested in the LW-PV panel group was only 6% lower than in the LW-Control group. On the other hand, in the case of higher watering, the difference was more pronounced at 29% (HW-Control vs. HW-PV panel). Several studies have suggested a potential correlation between high productivity under PV panels and elevated soil humidity compared to the soil humidity under full sunlight conditions [42, 43]. However, our study did not find a consistent correlation. Under the  
Figure 8: Average soil temperature (**a**) and humidity (**b**) resulting from measurements in each pot within both the control and PV panel groups. In the tables, the colored boxes denote statistically significant differences (light orange, \(p<0.01\); dark orange, \(p<0.001\)). Colorless boxes indicate the absence of statistically significant differences. HW-Control conditions, characterized by lower soil humidity, we harvested a higher number of fruits. Moreover, there were no significant differences in soil humidity between LW-Control, HW-PV panel and LW-PV panel plots, despite variations in the total fruit weight harvested. Hence, we may infer that higher soil humidity under PV panels could affect the size of tomato fruits, which was greater in the shaded plots. Furthermore, our study revealed substantial differences in the soil temperature. There was a difference of up to 7.7 \({}^{\circ}\)C between the soil temperature under PV panels and the soil temperature in the control plots. Such discrepancy, also recorded in the air temperature, could have influenced the stress responses of the plants in terms of survival, flowering, and fruit setting [44]. Delayed flowering in plants exposed to full sunlight plots might be linked to the higher maximum air temperature recorded in the first part of the air temperature profile, potentially inducing stress in tomato plants.