OptiDose: An optimal control for macronutrient dosing in hydroponics
Year: 2026
Type: article
Abstract: Achieving closed-loop hydroponic systems necessitates precise adjustment of individual macro- and micronutrients. However, nutrient management in hydroponics remains largely constrained to electrical conductivity (EC) and pH-based approaches, due to the complexity of steering individual ions and the coupling inherent in multi-element fertilizer formulations. In this study, an optimal control framework, OptiDose, is implemented to optimize daily fertigation strategies for hydroponically grown lettuce. The system integrates six fertilizer sources—calcium nitrate, magnesium sulfate, monopotassium phosphate, potassium nitrate, magnesium nitrate, and potassium sulfate—to maintain the concentrations of the macronutrients nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S) within crop-specific adequacy ranges. Five scenarios are tested in the simulator to evaluate system performance under varying operational constraints. Results indicate that OptiDose maintained nutrient concentrations across the entire growth cycle—without any nutrient deficiencies or toxicities—while markedly improving resource-use efficiency. Relative to a single-shot nutrient preparation (baseline), the strategy using properly sized solution tanks with daily recipe adjustment (Scenario 1) increased water-use efficiency sixfold and doubled fertilizer-use efficiency, achieving 34 g/L and 12.5 g/g, respectively. The results underscore the promise of element-specific fertigation for precision nutrient management in controlled environment agriculture.
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: hybrid
Estimated APC paid: $3,870
Funder: Salaojituksen Tukisäätiö sr
OpenAlex ID: W7123945999