Effect of different application methods of chelated zinc on growth, yield, and grain protein content of hybrid rice (Oryza sativa L.)

Abstract

A field experiment was conducted to evaluate the effects of different methods of chelated zinc (Zn) application on the growth, yield, and grain quality of hybrid rice. The hybrid rice cultivar Fengyou-293 was grown under a fertilizer regime of 150–70–70 kg ha⁻¹ N–P–K. The experiment was conducted using a randomized complete block design (RCBD) comprising six zinc (Zn) application treatments. The treatments included an untreated control with no Zn application (T₁), seedling root dipping followed by foliar Zn application (T₂), a single soil application of Zn at 3 kg ha⁻¹ applied 10 days after transplanting (DAT) (T₃), a split soil application consisting of 2 kg Zn ha⁻¹ at 10 DAT and an additional 1 kg Zn ha⁻¹ before panicle initiation (T₄), and a combined soil and foliar application involving 2 kg Zn ha⁻¹ applied to the soil at 10 DAT followed by a 1% Zn foliar spray before panicle initiation (T₅), and two foliar sprays applied at 10 DAT and before panicle initiation (T₆). The results demonstrated that zinc application significantly affected several yield and quality parameters. The split soil application of zinc (T₄) produced the highest number of grains per panicle (242.75), biological yield (14.80 t ha⁻¹), and grain yield (4.205 t ha⁻¹). Significant treatment effects were also observed for harvest index, grain sterility, and protein content. In contrast, plant height, number of tillers per hill, panicle length, and thousand-grain weight were not significantly influenced by the different methods of chelated zinc application. The results demonstrated that the split application of chelated zinc, with 2 kg Zn ha⁻¹ applied at 10 days after transplanting followed by an additional 1 kg Zn ha⁻¹ before panicle initiation, was the most effective zinc management practice for enhancing both grain yield and quality attributes of hybrid rice. Further research should focus on evaluating split applications of chelated zinc under diverse environmental conditions and integrating this approach with nutrient management to enhance crop productivity and zinc use efficiency. © 2026 The Author(s)