Short Description of the Technology

The University of Thessaly (UTH) leads the development of an innovative technology, titled “Cascade Soilless System for Reusing Effluents in Sequential Crops,” aimed at advancing the technology readiness level (TRL) from 5 to 7-8. This technology is part of Work Package 3 (WP3), which focuses on deploying novel solutions to reduce surface and groundwater pollution caused by nitrate and phosphate leaching and runoff. It forms an integral part of a holistic approach centered on nutrient recycling, precision fertilization, and nature-based solutions, all designed to improve nutrient use efficiency and reduce losses. The technology’s outcomes will include protocols for circular cropping systems in greenhouses and technologies for precision fertilization.

Within the Econutri project, UTH has implemented a cascade hydroponic system at its greenhouse facilities. In this system, the drainage nutrient solution from a primary (donor) crop is collected and reused to meet the needs of a secondary crop, typically more tolerant to salinity. As the solution is reused, it accumulates salts due to unabsorbed ions. However, the total drainage volume in this cascade system is significantly lower compared to conventional monoculture systems, leading to a more environmentally friendly discharge. This reduction in harmful effluents is achieved through the efficient removal of nitrates and phosphates, making the system’s drainage significantly less harmful to the environment than that of an open monoculture system.

Innovative Features

UTH has equipped the hydroponic system with an ion-selective electrode (ISE) installed directly within the hydroponic head, enabling real-time monitoring of nitrate and potassium concentrations. The ISE is integrated with the greenhouse’s existing programmable logic controller (PLC), allowing for automated monitoring and control of these key nutrients. This allows for continuous monitoring and optimization of nutrient management for secondary crops. The real-time data enables precise nutrient delivery, enhancing the system’s overall efficiency and reducing waste.

Type of Contribution

The combination of the cascade hydroponic system with real-time ISE maximizes water and nutrient use efficiency, while minimizing nitrogen and phosphorus leaching into the environment. This approach not only promotes sustainable and eco-friendly agricultural practices but also improves resource utilization, leading to cost savings for producers by requiring fewer inputs per unit area.

Benefits for farmers, the industry, and the environment

The cascade system, equipped with ISE offers multiple benefits: it reduces production costs per unit area, lowers the water and carbon footprints of crops, and minimizes the environmental impact by reducing groundwater pollution and fertilizer use. This technology contributes to the sustainability of greenhouse cultivation, while also enhancing producer profitability and ensuring more efficient agricultural processes.