Enhanced Zinc Management for Improved Productivity and Post-Harvest Nutrient Availability in Maize (Zea Mays L.)

During the rabi season of 2024–2025, a field experiment was conducted at the Research Farm, School of Agricultural Sciences, Malla Reddy University, Hyderabad, to evaluate the effect of different forms of zinc fertilization on the growth, yield and post-harvest nutrient availability of maize (Zea mays L.). The experimental soil was sandy clay loam in texture, moderately alkaline in reaction, low in organic carbon, nitrogen and phosphorus, high in potassium and deficient in zinc. The maize hybrid Pioneer 3546 was sown at a spacing of 60 cm × 20 cm in a Randomized Block Design with 15 treatments, each replicated thrice. The recommended dose of fertilizers (240:80:80 kg N:P2O5:K2O ha-1) was applied as 1/3 nitrogen with full phosphorus and potassium as basal, 1/3 nitrogen at knee-height stage (34 DAS) and the remaining 1/3 nitrogen at tassel initiation stage (56 DAS). Treatments included foliar applications of Zinc Sulphate, Zinc Gluconate, Zinc Glycine, Zinc EDTA and Zinc Oxide at varying concentrations and intervals, along with a basal application of Zinc Sulphate. Significant differences were observed among the treatments for all growth and yield parameters. The application of Zinc Gluconate @ 3 ml L-1 at 15, 30 and 45 days after sowing (DAS) recorded the highest plant height (236.8 cm), leaf area (4229 cm²) and total dry matter (291.7 g plant-1). The same treatment also produced the highest kernel yield (94.07 q ha-1), cob yield (102.75 q ha-1), stover yield (147.45 q ha-1) and harvest index (38.96%), followed closely by Zinc Oxide @ 3 ml L-1. The control treatment (RDF alone) consistently recorded the lowest values across all parameters. Post-harvest analysis revealed improved soil nutrient availability under foliar Zinc Gluconate, with nitrogen, phosphorus and potassium of 312.88, 15.78 and 205.00 kg ha-1, respectively, compared to the control (only RDF). The results clearly indicate that foliar application of Zinc Gluconate at 3 ml L-1 at critical growth stages is highly effective in enhancing maize growth, yield components and post-harvest soil nutrient status. The study demonstrates that the use of efficient zinc formulations can improve nutrient utilization and productivity of maize, providing a viable approach for sustainable intensification of cereal-based cropping systems.