Studies were conducted during the 2013 and 2014 cropping seasons at the research field of the University for Development Studies, Nyankpala in the Northern Region of Ghana to determine the effects of bulb size at planting and NPK 15:15:15 application rate on growth and yield of onion. The NPK 15:15:15 was applied at the rate of 0 (control), 80, 165 and 250 kg ha1. Three different bulb sizes: small (2.5-3.5 cm), medium (4.5-5.5 cm) and large (6.5-8.5 cm) were used. The treatment combinations were laid out in a randomized complete block design with three replications. Leaf length, number of sprouts and leaf number were measured from 1-7 weeks after planting. Also individual bulb fresh weight, cluster bulb fresh weight and number of bulbs were measured at harvest. Results indicated that the plants produced from large bulbs produced the highest vegetative growth whilst those from small bulbs recorded the least growth. The application of 80 kg ha1 of NPK 15:15:15 produced the highest number and fresh weight of bulbs at harvest whilst plants produced from small bulbs fertilized with 250 kg ha1 recorded the least bulb yield at harvest.
I.K. Addai and D.K. Anning, 2015. Response of Onion (Allium cepa L.) to Bulb Size at Planting and NPK 15:15:15 Fertilizer Application Rate in the Guinea Savannah Agroecology of Ghana. Journal of Agronomy, 14: 304-309.