The effect of solar radiation on the growth and development of hydroponically grown lettuce in two areas with different climates

Authors : Jonathan KUMMER, Demet ÇEKİN, Hani SEWİLAM

Pages : 92-100

View : 29 | Download : 20

Publication Date : 2022-09-30

Article Type : Research Paper

Abstract :Leafy vegetable production under a controlled environment by regulating lighting has many advantages. However, the high initial start-up and operation costs are limiting factors. In order to design an optimal lighting environment for plant growth, quality and quantity of the provided light energy must match each crop’s demand. For lettuce, this demand is established as a daily light integral insert ignore into journalissuearticles values(DLI); of 17 mol/m²/day within the photosynthetic active radiation insert ignore into journalissuearticles values(PAR); spectra. Sunshine data from the two considered locations Aachen and Cairo have been collected and edited. With that data, the available PAR-fraction was calculated with the Angstrom-Prescott equation and compared to the plants’ demand. The available sunlight energy exceeds the crops’ demand all year round in Cairo insert ignore into journalissuearticles values(maximum in June, five times higher than demand); and in the summer months in Aachen. In the winter months in Aachen the sunlight energy is lacking insert ignore into journalissuearticles values(only 14 % of the required DLI in December);. The results reveal that light balance tools like artificial light and shading nets provide promotion of lettuce growth and enhance hydroponic cultivation in semi-controlled environments. They also provide data for scaling advanced hydroponic cultivation.
Keywords : solar radiation, photoperiod, hydroponic, lettuce, daily light integral, photosynthetic active radiation