Nutrient Use Efficiency Evaluation

Fresh weight (mg) of root and leaves was measured at harvest (55 days after germination) using an analytical balance. The dry weight was measured by oven-drying at 70˚C for 72 h. The plant samples were analyzed for total N (TKN), NO₃^−, and NH₄⁺ using an EasyChem Plus analyzer (Chinchilla Scientific, Oak Brook, IL, USA). Total elemental analysis was conducted using ICP-OES (Thermo Scientific™ iCAP™ 7000 Plus Series, Waltham, MA, USA). The nitrogen use efficiency (NUE) percentage was calculated as a ratio of TKN x dry biomass (g)/N input (g) separately under HN and LN. For the rest of the minerals (Ca, Mg, K, P, Fe, Cu, Zn), nutrient utilization efficiencies (NuUtE) were calculated by taking the ratio of dry biomass per plant to mineral content using established methods (Corrado et al., 2021 (link)). Individual mineral use efficiencies were obtained by taking the ratio of individual mineral amounts recovered from plant tissue to the concentration (ppm) applied through fertilizers.