Effect of Nitrogen Fertilizer Rates and Intra Row Spacing on Bulb Yield of Onion (Allium cepa L.) at Shire, Northern Ethiopia

A field experiment was conducted to study the effect of nitrogen (N) fertilizer rates and intra row spacing on yield of onion (Allium cepa L. ) cultivar Bombay Red. Treatments consisted of a factorial combination of four rates of N (0, 50, 100 and 150 kg N ha-1) and four intra row spacing (4, 6, 8, and 10 cm) with inter row spacing of 20 cm. The experiment was laid out as a Randomized Complete Block Design with three replications. The analysis of variance revealed that the main effects of N and intra row spacing significantly affected average fresh bulb weight, bulb diameter, marketable yield, and total bulb yield.100 kg N ha. -1 was found the best rate of N to get optimum marketable bulb yield (31.455 t ha-1), total bulb yield (32.84 t ha-1) and average bulb weight (86.50 g). The results also revealed that intra row spacing of 6 cm was optimum. Combined Spacing of 6 cm x 20 cm with 100 kg N ha-1 is most favourable for onion cultivar Bombay Red production at Shire, northern Ethiopia.