Response of onion (Allium cepa L.) to crop geometry and nitrogen levels

A field experiment was conducted during rabi 2006–07 on loamy sand soils of Semi-Arid Tracts of Rajasthan at research farm of ATC, Ajmer (Rajasthan). The experiment comprising three levels of crop geometry, viz. 10x10,15x10 and 15x15 cm and four levels of nitrogen viz. 0, 50,100 and 150 kg/ha was conducted in factorial randomized block design with three replications. Application of 100 kg nitrogen being at par with 150 kg nitrogen/ha exhibited significantly higher, number of leaves, bulb weight, diameter and yield of bulb over lower levels of N. However application of 150 kg nitrogen resulted in significantly higher plant height and nutrient uptake over its lower levels. The closer crop geometry (10x10 cm) producedsignificantlyhigher bulb yield (308.33qjha) as compared to wider crop geometry (15x15 cm) but it was at par with intermediate spacing. However, wider crop geometry (15x15 cm) gave significantly higher growth and yield attributes viz, plant height (64.87 cm), number of leaves/plant (11.8), fresh bulb weight/plant (63.45 g) and diameter (5.08 cm). Wider spacing brought significant improvement in nitrogen uptake, though remained at par in phosphorus and potash uptake with intermediate spacing. Thus it is inferred that application of 100 kg N/ha with crop geometry of 10 x10 cm is better for realizing higher yield in onion production.