NFT with supplementary light as a technique to extend the production period of 'Scopatizzo' (Cucumis melo L.), even through the use of brackish water

‘Scopatizzo’, belonging to the Cucumis melo L., is a local variety grown in Apulia region, which is consumed as unripe melon. This local variety is characterized by its relatively small-sized fruits, which have a light and sparse fuzziness. At the greenhouse of the experimental farm ‘La Noria’ of the National Research Council, Institute of Sciences of Food Production (Mola di Bari, Bari) two experimental trials were conducted between September and November 2023 and between March and June 2024. In these trials, 'Scopatizzo’ plants were cultivated in the presence/absence of supplemental radiation provided by light-emitting diode (LED) technology and with the addition of NaCl in the nutrient solution (NS). In both trials, the cultivation technique used was closed-cycle NFT, aimed at increasing the efficiency of water (WUE) and nutrient use and proposing a cultivation system that reduces the production of waste from agricultural activities (substrate-free). In the first experimental trial the plants grown under LEDs showed an increase in productivity of about 300 g of fruits·plant-1 and a WUE approximately 4 L of NS·kg of fruit-1 better than the control. Instead, in the second experimental trial, the addition of 15 mM of NaCl in the NS resulted in a significant reduction in productivity compared to the control (more than 50%) as well as a reduction in WUE (almost 2.5 L of NS· kg of fruit -1). Even in this second cycle, the application of LEDs led to an increase of about 700 g of fruits·plant-1 in productivity and an increase in WUE of about 3 L of NS· kg of fruit -1. The research activity demonstrated that NFT is a valid cultivation technique for enhancing 'Scopatizzo' and that the application of LEDs provides advantages for the out of season production. Additionally, it was shown that the use of saline waters allows for acceptable fruit production, but with high NS consumption, as periodic renewals are necessary.