Influence of two different types of fertilizer on baby leaf lettuce (Lactuca sativa L.) in a hydroponic system

Abstract

Lettuce (Lactuca sativa L.) is one of the most popular leafy vegetables used in human nutrition. Owing to its nutrient and mineral content, and high concentrations of vitamins and fibers, lettuce is considered as beneficial for human health. The short growing season makes lettuce convenient for growth in hydroponic systems. This paper aimed to study the effects of different mineral fertilizers on development and chlorophyll content in lettuce cultivated in controlled hydroponic systems. The research was carried out during January-February 2024 at the Institute for Vegetable Crops Smederevska Palanka, Serbia. The commercial lettuce cultivar ''Jukebox'' was cultivated for 30 days in a peat substrate, in a hydroponic system with artificial illumination. For lighting, light-emitting diodes (LEDs) were used. Plants were illuminated with multispectral white light (350-700 nm) at the temperature of 23 ± 2ºC and photoperiod of 8/16h (day/night). The experiment was set up in three replicates. The treatments were: Commercial fertilizer (CHF) intended for hydroponic production and soluble mineral fertilizer (SMF), applied in two different EC rates (1.5 and 2.5 mS/cm). For the first 15 days, the experiment was watered every day for 15 minutes, later watering was done twice a day for 15 minutes at intervals of ten hours. After 30 days of cultivation in a hydroponic system, growth parameters (fresh plant mass, above ground biomass and number of leaves) and chlorophyll content were measured. The CHF treatment significantly (p≤0.01) increased the mass of the plant (13.94g) comparing to SMF treatment (9.79g) The values of leaf chlorophyll content was significantly higher on the CHF treatment (26.43 SPAD) comparing to SMF treatment (22.18 SPAD) on the lower level of probability (p≤0.05). Nevertheless, the differences in mass and chlorophyll content indicate that the nutrients in CHF are better used compared to the SMF treatment especially at the 1.5 mS/cm EC level.