Hydroponic cultivation offers a promising solution to water scarcity by using less water than traditional soil-based agriculture. Although the integration of silicon (Si) in hydroponic systems is still limited, its foliar application is crucial for optimizing plant growth, enhancing resilience, and improving productivity. Therefore, this study aims to explore the effects of silicon foliar application on growth, yield parameters, and photosynthetic activity of one of the most important fruit vegetables worldwide—tomatoes (Solanum lycopersicum L.)—cultivated in a closed hydroponic system. Tomato plants were subjected to a weekly silicon foliar spray (1 mM Na₂SiO₃) over a period of 10 weeks. Our results demonstrate that silicon foliar spray in hydroponically grown tomatoes significantly improved photosynthetic pigment concentration and enhanced the photochemical efficiency of the photosystems, particularly the quantum yields Y(I) and Y(II). Moreover, silicon treatment resulted in reduced energy dissipation within the photosystems, as indicated by decreases in Y(NPQ), Y(NO), and Y(ND), along with enhanced oxidation of PSI (P700ox). These physiological improvements were directly linked to increased stem width and length, and a substantial boost in plant dry weight compared with untreated controls. Consequently, the silicon foliar spray resulted in a significant increase in the number of racemes, flowers, and fruits. Ultimately, these enhancements culminated in a 69% increase in fruit biomass yield (r² = 0.70; p < 0.01), highlighting the positive impact of silicon on tomato productivity in hydroponic systems. These findings suggest that silicon foliar application optimizes growth and photosynthetic efficiency while reducing energy dissipation. Consequently, silicon supplementation enhances tomato productivity in hydroponic systems, offering a promising solution for increasing yields in water-efficient agriculture.

The greenhouse serves as an enclosed structure designed to create a conducive environment for agricultural productivity, irrespective of the challenges posed by seasonal variations. Recognizing the contemporary complexities in agricultural management, our research endeavors involve the development of a comprehensive numerical model and the establishment of an experimental setup to delve into the nuanced impact of mechanical ventilation. Specifically, the study investigates the influence of four different entrance velocity values on airflow dynamics within agricultural greenhouses. The results illuminate the direct correlation between inlet velocity and various crucial variables, including temperature distribution, velocity field distribution, DO irradiation distribution, and static pressure distribution. Notably, at Vint = 12 m.s-1, the maximum temperature remains below Tmax = 307 K, while at Vint = 3 m.s-1, it reaches Tmax = 327 K. This underscores the pivotal role of accurate modeling and control for the optimal management of agriculture in the central region of Tunisia, particularly in Sfax.