AGRONOMIC AND ECONOMIC STUDIES OF LETTUCE PRODUCTION UNDER HYDROPONIC SYSTEMS.

This study was conducted at the Central Laboratory for Agricultural Climate (CLAC), Agricultural Research Center, Giza, Egypt, during two winter seasons of 2022 and 2023. To investigate the efficiency of two hydroponic systems (flat nutrient film technique "F-NFT" and deep water culture "DWC") under three nutrient solution concentrations (1.2, 1.5 and 1.8 dSm-1), three number of irrigation times: (24, 36 and 48 per day) and interaction of them on growth and yield of lettuce. Treatments were arranged in a split split plot design with three replicates. Measurements were i.e., number of leaves, plant fresh weight, total yield (Kg/m2), N, P, K and nitrate contents in leaves, chlorophyll reading, water and power use efficiency/m² and economic study. The results indicated that using F-NFT, solution concentration 1.8 dSm-1 and 48 irrigation times per day provided the highest values for all tested parameters more than other treatments. While, from the economic study illustrated that the cultivation of lettuce in the F-NFT system, using a nutrient solution concentration of 1.5 dSm-1 and 48 irrigation times per day gain the highest net profit under a greenhouse covered by netting during the winter season. [ABSTRACT FROM AUTHOR]