Improving Essential Oil, Pigments, and Mineral Accumulation in Basil Through Integrated Silicon and Nano‐Fertilizer Treatments in Aquaponics

Innovative agricultural production systems and effective nutrient management approaches are essential to meet an escalating global demand for sustainable food. The influence of three delivery systems: silicon (Si), a nano‐fertilizer (Nanogreen), and a chelated micronutrient fertilizer (Disper Complex GS) was evaluated on Ocimum basilicum L. growth (height and fresh weight), physiological characteristics (photosynthetic pigments), the amount of macro and micronutrients absorbed, and essential oil yield in a closed aquaponic growing system. A completely randomized design (CRD) based on a Taguchi L9 orthogonal array was used, and utilized three replications within each treatment. The treatments consisted of three levels of Si (0, 0.1, and 0.2 mM), three levels of the nano‐fertilizer (0, 1, and 2 g L −1 ), and three levels of Disper (0, 2, and 4 g L −1 ). All fertilizers were applied as foliar sprays so as to avoid disruption of the fish's aquaponic water and to maintain fish safety. Overall, each of the treatment combinations produced statistically significant improvements over the controls in plant growth, total biomass production, photosynthetic pigment accumulation, essential oil yields, and macro‐ and micronutrient content. In addition, the maximum improvements in plant height, fresh weight, chlorophyll content, essential oil yield, and macro‐ and micronutrient accumulation occurred when 0.2 mM Si, 2 g L −1 of the nano‐fertilizer, and 4 g L −1 Disper were applied. However, antioxidant activity decreased with high input treatments, suggesting lower levels of oxidative stress due to a higher level of nutrition. Correlation and regression analysis indicated significant positive correlations between growth, mineral nutrient uptake, and pigment accumulation, with zinc being a critical mineral. These findings provide an effective strategy for sustainable basil production in aquaponic systems through optimized nutrient management.