Influence of Nitrogen and Phosphorus Fertilizers on Bulb Yield and Yield-Related Attributes of Onion (Allium cepa L.) in Fogera Area, Northwest Ethiopia

Abstract

Aim: Onion is one of the most important vegetable crops grown under irrigation in the Amhara Region of Ethiopia. However, its productivity is affected by sub-optimal fertilization. The present research was conducted to investigate the response and economic returns of onion to N and P fertilizers application under irrigation.
 Study Design: Randomized Complete Block Design in Factorial Arrangement with three replications.
 Place and Duration of the Study:  The research was conducted in 2020 and 2021 in the Fogera area of Northwest Ethiopia.
 Methodology: Four levels of N (0, 46, 92, and 138 kg N ha-1) and three levels of P (0, 46, and 92 kg P2O5 ha-1) were factorially combined and laid in a randomized complete block design with three replications.
 Results: The results showed that the yield and yield components of onion were significantly affected by the main effects of N. However, the main effects of P and its interaction with N did not significantly influence the growth and yield of onion. The highest plant height, number of leaves per plant, bulb girth and marketable bulb yield were recorded from the application of N138 statistically at par with N92. The maximum net economic return was obtained from the application of N138.
 Conclusion: Application of 138 kg N ha-1 was the economic optimum rate for maximum bulb yield of onion in the study area. Further investigation on the response of onion to P is recommended.