EBB-AND-FLOW AND FLOATING SYSTEMS TO GROW LEAFY VEGETABLES: A REVIEW FOR ROCKET, CORN SALAD, GARDEN CRESS AND PURSLANE

The interest for functional foods and the consumption of fresh-cut vegetables are rising in many EU countries and in the USA. The intensive winter season cultivation of vegetable crops causes more sensitive and hence disease-prone plants. This leads to an intensified application of pesticides, increasing chemical residue risks. Vegetable crops are facing the banning of fumigant methyl bromide application for ground disinfections. Furthermore, chain quality production has become crucial in terms of food safety and environmental impact. Thus, protected cultivation is increasingly shifting from Traditional Culture System (TCS) - in soil - to Soilless Culture System (SCS). The SCS allows to control growth factors and to obtain clean raw material at harvest improving its safety and quality. Among the SCSs, Ebb-and-Flow (EF) and Floating (FL) Systems are relatively cheap and easy-to-use hydroponic systems. They are suitable to produce vegetables both with a short cultural cycle and with a high plant density, and can be considered as an efficient system to produce leafy vegetables, either baby leaves or baby bushes. Controlling the nutrient solution and managing plant growth according to environmental conditions allow decreasing nitrate content in the edible product. Nitrate accumulation, however, is very variable among species. The full control of the inputs that SCS provides should reduce the environmental impact and contribute to product quality standardization. Different irrigation systems (EF and FL), nutrient solutions (N levels and NO₃^-/NH₄⁺ ratios), culture systems (SCS and TCS) were investigated from years 2000 to 2005. Were considered species commonly cultivated (rocket and corn salad) and minor species, important for their functional content or traditional use (purslane, garden cress) and those with potentiality to be introduced in the fresh-cut supply chain.