Effect of nitrogen and bio-fertilizer on yield and quality of Rabi onion (Aluum cepa L) cv. Puna red

A field experiment was conducted on sandy loam soil during rabi season of 1999–2000 to study the effect of four levels of nitrogen (25, 50, 75 and 100 kg ha⁻¹) and two sources of biofertilizer viz., Azotobacter (A₁) and Azospirillum (A₂) on yield and quality of onion bulb (Allium cepa L). Results indicated that the application of nitrogen @100 Kg N ha⁻¹ significantly increased bulb yield and quality attributes. The treatment combination N₄A₁S₂ (100 kg N ha⁻¹ + Azotobacter with seedling dipping) gave highest bulb yield and fresh weight of bulb, followed at par by N:AIS₂ (75 Kg N ha⁻¹ + Azotobacter with seedling dipping). In economics, the maximum B:C ratio (2.26:1) was recorded with the treatment combination of N:AIS₂ as compared to N₄A₁S₂ with a lower B:C ratio (2.24:1) due to additional cost of urea and non significant difference between these two treatments regarding yield of bulbs. Thus, the treatment combination N₃A₁S₂ was the best.