Cascade hydroponics enhanced water and nutrients use efficiency in a greenhouse cucumber-melon crop combination

• Cucumber as donor and melon as receiver crop were tested in a cascade soilless system. • Compared to monoculture the cascade system increased the water use efficiency by 22%. • Compared to monoculture the cascade system increased nutrients use efficiency by 20%. • Compared to monoculture the cascade system reduced about 80% nutrients leaching. Enhancing the sustainability of horticultural crops in the Mediterranean region is of great importance, with a particular focus on the simultaneous reduction of water and fertiliser consumption and the improvement in crop productivity. In the current study, the efficacy of a cascade soilless system was assessed, which utilised the drainage of a cucumber (donor) cultivation to meet the nutritional and water needs of a melon (receiver) crop, both grown in perlite slabs. Melon crop irrigated with standard nutrient solution, served as control treatment. The cascade system was assessed in terms of water (WUE), nitrogen (NUE), phosphorus (PUE), and potassium (KUE) use efficiency. In addition, the total consumption and the mineral composition of the supplied nutrient solution during cropping were monitored and the N and P emissions to the environment were estimated. The effects of the treatments on plant growth and yield as well as the nutrient absorption of the melon crop, was also examined. The results showed that the WUE of the cascade system demonstrated a 22% increase compared to the cucumber monoculture system. The NUE and PUE increased substantially by 21.7% and 21.8% compared to the monoculture system respectively, while the KUE increased by 9%. Notably, plant growth and yield of the receiver crop were not affected when fertigated with the drainage solution derived from a cucumber crop. Finally, the implementation of the cascade system contributed to a remarkable reduction in N and P leaching into the environment by 70% and 86%, respectively. These results underscore the potential of cascade soilless systems as a sustainable and resource-efficient approach in Mediterranean horticulture.