Cascade Hydroponics as a Means to Increase the Sustainability of Cropping Systems: Evaluation of Functional, Growth, and Fruit Quality Traits of Melons

The necessity of optimizing the nutrient and water efficiency in conventional hydroponics and enhancing their sustainability has given rise to the concept of cascade cropping systems. These achieve high water and resource use efficiencies, together with a lower environmental footprint, which is especially important for Mediterranean areas. However, scientific questions about the mechanisms that drive productivity in this system remain to be answered. This study aimed at a comprehensive evaluation of crop performance in cascade systems in terms of morphoanatomical and functional responses, also including product quality parameters, which influence the marketability of the fruit. In a three-month experiment, the dynamics of melon’s photosynthetic light use efficiency, pigment contents, growth parameters, and leaf compactness were assessed in a cascade system using drainage of tomato cultivation in comparison to classic hydroponic melon. The fruits’ chroma, hardness, total soluble solids, and pH were also measured. Comparable plant functional responses in the control and cascade melon plants resulted in similar growth and morphoanatomical traits. The fruit quality attributes were also found to be almost identical. It is proposed that the cascade system is both effective and sustainable in regions facing climatic and water scarcity pressures, such as those that are prevalent around the Mediterranean basin.