Effectivity of some Hydroponic Systems on Quality and Productivity of two Species of Lettuce Plant (Romaine and Iceberg)

The research was carried out on the Abu Jerash farm at the Faculty of Agriculture at the University of Damascus in the 2020-2021 season, and in the second season (repeating the experiment) 2021-2022 within a plastic house with a temperature of 23 degrees Celsius with the aim of studying the effect of three different methods of hydroponics (nutrient film film, irrigation system Drip and float cultivation) in some chemical and physical qualitative characteristics of romaine and iceberg lettuce varieties using three different concentrations of Hoagland nutrient solution (100%,50%,25%). The results of the analysis of variance showed that the average coefficients of hydroponic farming methods and the average coefficients of nutrient solution concentrations had a positive effect on some growth and production indicators for the two cultivated lettuce varieties, Romaine and Iceberg. The significant superiority of the average treatment of the hydroponic system with floatation over the average treatment of the hydroponic system with drip irrigation in terms of root system length was observed. Its value reached 32.2 cm, the diameter of the head reached 28.26 cm, and the wet vegetative weight of the head amounted to 440 g, And chlorophyll A and B with values reaching (16.96,11.23) mg/100ml respectively, in addition to the significant superiority of the average100% nutrient solution concentration treatment over the average 25% nutrient solution concentration treatment in head diameter of 30.6 cm, leaf area of 335.4 cm2, and weight. The total value of the plant was 573.43 g. The results of the analysis of variance indicated that the Romaine variety was superior to the Iceberg variety in the leaf content of potassium with a value of 3.2%, and the percentage of total dissolved solids with a value of 12.16%.