INTEGRATED ZINC MANAGEMENT WITH ZINC FERTILIZERS AND ZINC-SOLUBILIZING BACTERIA FOR IMPROVED GROWTH, PHYSIOLOGY, AND YIELD OF RICE (ORYZA SATIVA L.)

Abstract

Zinc (Zn) deficiency is an important nutritional constraint affecting rice productivity and plant physiological performance. Field experiments were conducted at the Anbil Dharmalingam Agricultural College and Research Institute, Tiruchirappalli, Tamil Nadu, India, during 2024 and 2025 to evaluate the effect of integrated Zn nutrition involving zinc sulfate (ZnSO₄), zinc-solubilizing bacteria (ZSB) and foliar Zn application on rice. Rice variety TRY 5 was evaluated under eight Zn nutrition treatments in a randomized block design with three replications. The treatments consisted of farmers' practice, ZnSO₄ at 25 and 37.5 kg ha⁻¹, ZSB at 2 kg ha⁻¹, combinations of ZnSO₄ and ZSB, and combinations of ZnSO₄, ZSB and 0.5% foliar ZnSO₄. The experimental soil was clay loam with pH 8.26, electrical conductivity 2.029 dS m⁻¹, organic carbon 0.32% and available Zn 0.48 mg kg⁻¹. Biometric observations were recorded at active tillering, panicle initiation and harvest stages, whereas physiological observations were recorded at the vegetative stage. Integrated Zn nutrition substantially improved rice growth, physiological characteristics and yield. The highest plant height (137.6 cm), tiller number (412 m⁻²), dry matter production (11841 kg ha⁻¹), SPAD value (49), chlorophyll content (4.12 mg g⁻¹), panicle number (344 m⁻²), grain yield (5434 kg ha⁻¹) and straw yield (6943 kg ha⁻¹) were recorded with ZnSO₄ @ 37.5 kg ha⁻¹ + ZSB @ 2 kg ha⁻¹ + foliar ZnSO₄ @ 0.5%. The same treatment recorded the lowest Na⁺/K⁺ ratio (1.8). Grain yield under T8 was 27.2% higher than farmers' practice. The findings indicated that integration of soil-applied ZnSO₄ with ZSB and foliar ZnSO₄ was an effective strategy for improving growth, physiological performance and productivity of rice under the experimental conditions.