Growth and growth indices of rice (Oryza sativa L.) as influenced by different sources of nano urea and mulches

Enhancing nutrient use efficiency and optimizing plant growth through nano-based inputs and eco-friendly mulching strategies is a promising approach for sustainable rice production. A field experiment was conducted during the kharif 2024 at the Instructional Farm, Department of Agronomy, DBSKKV, College of Agriculture, Dapoli to study the influence of different sources of nano urea and mulches on growth indices of kharif dibbled rice (Oryza sativa L.). The experiment was laid out in a split-plot design with three main plot treatments: Nano urea (market product) @ 40 ppm (N₁), Nano urea synthesized @ 40 ppm (N₂), and Nano urea conjugate @ 40 ppm (N₃) and five subplot treatments: 100% wool mulch (M₁), 100% wool mulch with micronutrients (M₂), polythene mulch (silver-black, 30 microns) (M₃), drip HDPE mulch (M₄), and no mulch (control) (M₅). The results indicated that, nano urea conjugate (N₃) significantly improved plant height, dry matter accumulation and showed higher values for growth indices such as absolute growth rate (AGR) for plant height and dry matter accumulation and crop growth rate (CGR), similarly for treatment M₂ (100% wool mulch with micronutrient, 200GSM) and treatment N₁- nano urea (market product) @40ppm and M₅ showed higher values for relative growth rate (RGR) and net assimilation ratio (NAR) across all growth stages.