Multi-objective optimization identifies cultivation strategies for balancing yield, quality, and resource efficiency in hydroponic netted melon

Managing the trade-offs between yield maximization and fruit quality is a critical challenge in hydroponic melon production. To identify optimal cultivation strategies, we evaluated three netted melon cultivars (‘Dalgona’, ‘Hero’, and ‘Kingstar’) under restricted (10 L) versus standard (20 L) substrate volumes and two planting densities (3 vs. 4 plants/slab). We utilized Pareto frontier analysis to visualize the balance among fruit quality, resource use efficiency, and economic performance. The analysis revealed three distinct optimal strategies targeting specific market segments: profit-maximization (‘Hero’, 10 L, 4 plants/slab, 268% return on investment [ROI]), premium-quality focus (‘Dalgona’, 10 L, 3 plants/slab, 100% premium-grade), and resource-efficiency (‘Kingstar’, 10 L, 3 plants/slab, water productivity of 5.7 kg m⁻³). While increasing planting density enhanced total yield by 20.7%, it compromised internal fruit quality. The 10 L substrate volume achieved superior economic performance (ROI 42.9%–268.0%) across all cultivars by inducing a root restriction effect that improved sugar content and water productivity compared to the 20 L standard. These findings provide a quantitative decision-support framework enabling producers to select optimal parameter combinations tailored to their specific management objectives.