Micronutrient-Doped Carbon Nanofibers Granulated with Secondary Nutrients: A Novel Approach to Improve Zn Translocation in Tomato (Solanum Lycopersicum L.)

Aim Zinc deficiency in soils severely limits crop productivity, mainly in Indian soils, particularly in Zn-sensitive crops like tomato. To address this challenge, a novel micronutrient-enriched carbon nanofiber granulated with secondary nutrients (M-CNF GSN) was developed to improve zinc delivery and evaluate its effects on Zn uptake and translocation in tomato. The M-CNF GSN system was designed based on the high surface area and functionalized surfaces of carbon nanofibers, which are expected to facilitate Zn delivery.Methods A pot culture experiment was conducted using acidic and zinc-deficient soil (pH 5.87; DTPA-extractable Zn: 0.79 ppm), comprising 14 treatments including a control, recommended dose of fertilizers (RDF), four zinc sulfate (ZnSO4) treatments, four M-CNF GSN treatments and four granulated secondary nutrient (GSN) treatments.Results Among them M-CNF GSN outperformed conventional ZnSO4, particularly at 1.25 kg Zn ha−1, achieving: 46.53 ppm Zn in shoots vs. 38.38 ppm in ZnSO4‑treated plants at 60 DAT, MCNF-GSN produced a significantly (p < .05) higher shoot-to-root Zn ratio (2.7-fold) than ZnSO4, indicating efficient systemic translocation, enhanced vegetative growth (111.70 cm plant height, 23 branches/plant) and accelerated flowering (20.7 days to first bloom). Hierarchical clustering revealed distinct Zn distribution patterns: M-CNF GSN treatments was associated with greater Zn accumulation in aerial tissues, while ZnSO4 led to root-bound accumulation (67.9 ppm in roots).Conclusion MCNF-GSN appeared to alleviate the negative effects associated with high calcium availability by stabilizing Zn2+ solubility and reducing fixation. This study indicates M-CNF GSN may become a sustainable technique for improving Zn use efficiency in Zn-deficient soils. Its dual function nutrient delivery and soil conditioning aligns with precision agriculture goals, offering a scalable solution to enhance crop resilience and yield.