Sustainable nitrogen management in fodder oats: Performance of foliar nano-urea on yield, quality and soil health optimization

Efficient nitrogen management in fodder oats is critical for optimizing productivity and forage quality while minimizing environmental losses. Nano-urea offers potential to enhance nitrogen-use efficiency under reduced basal nitrogen (N) regimes. A two-year field study (2022-23, 2023-24) at Central Agricultural University, Imphal, India, evaluated ten N management strategies combining basal N levels (0-100% RDN) with foliar sprays of nano-urea and conventional urea in single-cut fodder oats (Avena sativa L.). Foliar nano-urea @ 6 ml L^-1with 75% RDN (T₇) produced the highest green fodder (379.5 q ha^-1) and dry matter yield (82.6 q ha^-1), exceeding full conventional N (100% RDN) by 2.8% and 1.5%, respectively. Crude protein yield (8.99 q ha^-1) and economic returns (B:C = 2.09) were also maximized in T₇. Soil residual N (261 kg ha⁻¹) and P-K levels were significantly higher under nano-urea treatments compared with conventional fertilization. Principal component analysis revealed T₇ and T₂ as the most productive and profitable treatments, explaining 72.6% of total trait variability. Foliar nano-urea allows a 25% reduction in soil-applied N without compromising yield, forage quality, or profitability while improving soil nutrient status. Nano-urea thus represents a sustainable and cost-effective N management strategy for fodder oat production systems.