Influence of nano Zn formulations on rice cultivars under salt affected calcareous soils of Bihar

The field experiment, conducted at RPCAU, Pusa, Bihar, during Kharif 2022, to assess the effects of zinc treatments—control (no zinc), ZnSO4 foliar spray @ 0.5% (Zn1), nano zinc @ 20 ppm (Zn2), nano zinc @ 50 ppm (Zn3), and soil-applied ZnSO4 @ 50 kg ha–¹ (Zn4) on rice cultivars CSR 23 and DRR Dhan 48, in a split-plot design with recommended fertilizers, showed significantly enhanced tiller numbers, filled grains per panicle, and yields with Zn4 and Zn3 achieving the highest grain yields (3490 and 3430 kg ha–¹), respectively. DRR Dhan 48 outperformed CSR 23 in yield and nutrient uptake. Nitrogen content was highest with Zn4 (1.30% in grain, 0.50% in straw). Zinc content in grain and straw was significantly increased by Zn4 and Zn3, demonstrating nano zinc’s superior efficacy. Nano zinc, particularly at 50 ppm, is a sustainable alternative to conventional ZnSO4, enhancing rice productivity and nutritional quality in subtropical humid climates.