Effect of Different Nitrogen Sources on Growth, Yield and Seed Quality Parameters in Onion under Mid-Hill Conditions of Himachal Pradesh, India

Selecting the appropriate nitrogen source for onion cultivation requires alignment with specific production objectives. To improve seed yield and quality of onion, a study was conducted in 2020-2021 at Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), using nine treatments with varying nitrogen sources (CAN, urea and calcium nitrate) in RCBD with three replications. Treatment Trt1 in which 100% N (147.5 g/plot)was applied as CAN showed superior vegetative growth, early bolting (91.33 days), highest umbel size (7.43 cm), seeds per umbel (1143.80), and seed quality traits such as germination (91.50%), seedling vigour and lowest electrical conductivity (0.109 dS m⁻¹). However, Treatment Trt5 (75% CAN + 25% calcium nitrate) excelled in leaf length and seed yield (766.52 kg ha⁻¹). Both Trt1 and Trt5 showed high nitrogen use efficiency and residual soil nitrogen. Moreover, T1 recorded the highest benefit-cost ratio (3.53), making it the most effective nitrogen source for enhancing onion seed yield and quality under mid-hill conditions of Himachal Pradesh.