Application of Numerical Simulations for Optimization of Soilless Culture Systems.

With the global population projected to grow to more than 8 billion by 2024, irrigated agriculture faces momentous challenges to keep up with the increasing demand for adequate food supplies, especially in the arid and semi-arid regions of the world. As a result, soilless culture is regaining increased attention as it allows a more sustainable management of production resources along with higher achievable crop yields when compared to conventional agricultural production. To aid with the design of sustainable soilless production systems, we performed comprehensive physicochemical characterization of commonly employed soilless substrates such as perlite, volcanic tuff, coconut coir, Growstones, and mixtures thereof in conjunction with numerical modeling (HYDRUS-3D) of water and nutrient transport to not only provide design guidelines for growth module geometry and irrigation management, but also to optimize substrates by mixing organic and inorganic constituents at different ratios. To simulate water transport, a realistic root water uptake model for tomatoes was implemented based on feedback from greenhouse growth experiments. Non-equilibrium solute transport considering first-order decay reactions to predict NH4+, NO3–, and H3PO4 transport was simulated to provide feedback for fertigation management. Preliminary results will be presented and the potential of obtained findings for the design of soilless systems will be discussed.