Influence of nitrogen levels, organic amendments and foliar nutrition on growth and yield performance of rice (Oryza sativa L.)

Nitrogen (N) is an essential macronutrient for crop growth and its efficient management is crucial for sustainable rice production and the prevention of soil nutrient depletion. Despite extensive research, knowledge gaps remain regarding root-soil interactions for efficient N uptake, root-shoot coordination for N utilization and integrated nutrient management strategies to enhance nitrogen use efficiency and yield in rice. A field experiment was conducted at the Experimental Farm, Department of Agronomy, Annamalai University in 2024, using a randomized block design with nine treatments replicated thrice. Among the treatments, T₁ (100 % recommended dose of fertilizer: 120:40:40 kg ha-1) recorded the highest plant height (102.67 cm), no. of tillers (402 m-2), leaf area index (5.41), dry matter production (10,985 kg ha-1), crop growth rate (5.74 g m-2 day-1), absolute growth rate (0.0861 g plant-1 day-1), grain yield (4,978 kg ha-1) and straw yield (7,126 kg ha-1). This was followed by T6 (75 % RDN through urea + 25 % RDN through urban compost + 100 % P and K with foliar application of ZnSO₄ at 0.5 % and boron at 0.3 % at 25 and 50 DAT), which was on par with T4 involving biochar-based N substitution. The results demonstrate that partial replacement of chemical nitrogen with organic amendments, coupled with targeted foliar Zn and B application, improved nutrient uptake efficiency, reduced nitrogen losses and sustained crop productivity. Such integrated nutrient management practices offer a viable pathway to reduce urea dependency, enhance soil health and ensure long-term sustainability of rice agroecosystems.