Production possibilities of some leafy vegetables in floating system

In this study conducted in a greenhouse during the winter-early spring 2016-2017, it was aimed to determine the production possibilities of some leafy vegetables (rocket, spinach, garden sorrel and purslane) in the floating water culture system, the suitability of the winter nutrient solution receipt used for lettuce to the production of these greens and the effects of different nutrient solution concentrations in the process. Cultivation was carried out in trays, in aerated nutrient solutions on strofoam multipot and seeds were sowing into peat on 24.11.2016 and 21.02.2017 for 1st and 2nd production period, respectively. Each seed is inserted to each hole (17 cc) in strofoam multipot with 210 cells (957 plant m-2). Following germination in the germination chamber (dark, 12-18ºC, 80% RH, 3-5 days), the seed multipots were moved to climate controlled greenhouse for adaptation. After emergence, the seedlings were transferred to water culture on 07.12.2016 for 1st period and on 10.03.2017 for 2nd period. Plant nutrition was applied as "full dose" (with complex element content, mg L-1: N 150, P 50, K 150, Ca 150, Mg 50, Fe 5.0, Mn 0.50, Zn 0.05, B 0.50, Cu 0.03, Mo 0.02), "half dose" (with macro elements reduced by 50%) nutrient solution and "water" (without nutrients) and as they were reduced in trays, they were replenishment, EC and pH values were recorded. On the type basis, two multipots were used for each subject and the evaluations were made over 4 repetitions (n:105). The vegetables grown as baby leaves were harvested when they were 10-17 cm in length, and the vegetables were harvested 3 times at one week intervals in both periods. Findings of the study showed that plant growth, yield, quality, and water consumption vary depending on the concentration of nutrient solution as well as the temperature during the growing season. Especially in the 2nd period when the temperatures were higher, harvests were made 4 weeks after sowing, and yield increase and earliness were achieved. It was observed that as the concentration of nutrient solution decreased, yield values decreased in all types, and there was no statistical difference between full dose and half dose applications in many measured parameters. As the nutrient solution concentration decreased, vitamin C content increased and nitrate content decreased. Leaf N, P, K and Fe element contents decreased as the nutrient solution concentration decreased, whereas those of Ca and Mg increased. Plant water consumption was higher in the 2nd period and in dose-applied subjects. The pH value of the nutrient solution decreased with increasing nutrient solution concentration in all species, while the EC value increased. When all the data obtained from the study are evaluated together; it is suggested that rocket, spinach, garden sorrel and purslane species can be grown as a baby leaf in a floating water culture with used nutrient solution receipt and that in addition to reducing nitrate content, half-dose application may be preferred in terms of yield and water consumption due to being in the same statistical group with full-dose application, and that greens production should be done during early spring season in greenhouse conditions for high yield and quality.