Optimizing iron and zinc nutrition in deep-water culture and nutrient film technique enhances growth performance and nutritional Quality of Tomato

This study evaluated the effect of two hydroponic techniques namely Deep-Water Culture (DWC) and Nutrient Film Technique (NFT) in combination with varying concentrations of Fe and Zn (5, 10, 15, and 20 ppm) on the growth and biochemical composition of the tomato cultivar Reo Grande. Growth parameters including plant height, number of leaves, branches, and fruits were maximized at 10 ppm (59.8 cm, 129.0, 37.0, and 29.0 per plant, respectively), while the number of buds per plant (27.0) was highest at 15 ppm of Fe and Zn in the DWC system compared to NFT. Proximate composition of plant parts (green leaves, diseased leaves, and fruits) showed higher values in DWC, with notable increases in moisture (18.96%), crude protein (9.4%), crude fiber (8.24%), crude fat (4.31%), ash (4.89%), and nitrogen-free extract (84.62%). Similarly, mineral analysis revealed that Na (109 mg/kg), K (668.25 mg/kg), Ca (186 mg/kg), Mg (217.24 mg/kg), P (385.21 mg/kg), Ni (0.49 mg/kg), Fe (5.58 mg/kg), Zn (3.75 mg/kg), Co (21.45 mg/kg), Cu (1.41 mg/kg), and Mn (1.41 mg/kg) were generally higher in fruits, followed by diseased leaves and green leaves, in the DWC system. The effects of nutrient concentration, plant part, and their interaction were significant in most cases (P<0.05). Overall, the results demonstrated that the DWC system, particularly at 10 and 15 ppm concentrations of Fe and Zn, had a profound influence on the growth and biochemical composition of Reo Grande tomatoes, highlighting its potential for optimizing hydroponic cultivation practices.