Estudo de processos otimizados na agricultura em ambientes controlados

Abstract

Cultivating plants in controlled environments offers ideal conditions for their development, leading to superior growth rates, yields, and product quality. To successfully grow crops, it is essential to consider various parameters, including photoperiods, light intensity, nutrient concentration, temperature, and relative humidity. Additionally, microbiological control is crucial in hydroponic systems. These factors are vital for enhancing crop productivity and quality. The primary aim of this study was to optimize the growth of vegetables, specifically the species Lactuca sativa (lettuce), by considering specific process variables such as photonic supplementation with light-emitting diodes (LEDs), photoperiods, microbiological control, and nutrient concentration. To achieve this, four distinct chapters were developed: (II) enhancement of microbiological quality in hydroponic solutions, (III) optimization of nutrient solution concentration and light photoperiods, (IV) reduction of the time required to reach the plant's adult phase, and (V) analysis of photonic supplementation with fractional energy dose delivery and wavelength variations after parameter optimization. The study evaluation included phytochemical and qualitative analyses, where areas, masses, pigment concentrations, phenolic compounds, and antioxidant capacity were calculated, along with micronutrient and macronutrient content. The results indicated that in Chapter (II), applying an ultraviolet-C (UV-C) decontamination system in the hydroponic solution accelerated plant growth while maintaining nutritional values comparable to or superior to those of the groups without this system. In Chapter (III), the combination of low light intensity and long photoperiods, such as 18 and 20 hours, improved photosynthetic pigment content, biomass gain, area, phenolic compounds, and antioxidant capacity. Chapter (IV) enabled the development of a new growth protocol that reduced the conventional growth cycle from 8-10 weeks to just 4 weeks for the plant to reach the adult phase. Finally, in Chapter (V), the results of the study on photonic supplementation in fractionated light regimes, evenly distributed across different wavelengths, gradually increased nutrients throughout the plant's growth cycle, enhancing the area and mass of the lettuces. In conclusion, the results indicate that it is possible to cultivate lettuce in just four weeks while maintaining nutritional and physiological levels equivalent to those achieved in traditional indoor cultivation, which typically requires 50 days. This efficiency was achieved by using prolonged photoperiods of 18 hours with low light intensity. Furthermore, the spectral effect of light proved crucial for plants' functional growth, highlighting the importance of different wavelengths and their distribution throughout the plant's development cycle.