S06 - Session P2 - Development of a water flow and nutrients concentration simulation model for cascade hydroponic systems

Authors: Nikolaos Katsoulas *, Angeliki Elvanidi, Eleni Karatsivou, Vangelis Vassiliadis

In a cascade hydroponic system, the used nutrient solution drained from a primary crop is directed to a secondary crop, enhancing resource-use efficiency while minimizing waste. Nevertheless, the inevitably increased EC of the drainage solution requires salinity-tolerant crops. However, one of the biggest challenges in this case in recycling the drainage solution in those systems is the estimation of nutrients concentration in the drained nutrient solution at each stage of the cascade system, and the salinity management in the system. Monitoring nutrients concentration in the nutrient solution, at frequent intervals and at various positions is an option but it requires a significant number of samples to be analysed. To facilitate the practical application of drainage nutrient solution management, a simulation model of nutrients concentration in a cascade system has been developed. The system has been built to simulate the nutrient flow in a series of three crops: a primary, a secondary and a tertiary crop. The drained nutrient solution from the primary crop is used to fertigate the secondary crop while the drained solution from the secondary crop is used to fertigate the tertiary crop. After validation, the model will be used for different case studies of cascade crops. This work presents the model developed and makes also preliminary presentation of a case study with tomato used as primary crop and parsley as secondary crop. The drainage solution mixing strategy applied enabled different amount of drainage solution to be used from each crop. Based on the scenarios studied, the nutrients concentration at the different crop systems were studied. This research has been co-financed by the European Union and Greek national funds through the National Action "Bilateral and Multilateral E&T Cooperation Greece-Germany" (project code: T2DGE-0893).