Response of Irrigated Onion (Allium cepa L.) to Nitrogen and Phosphorus Fertilizers at Ribb and Koga Irrigation Schemes in Amhara Region, North western Ethiopia

Abstract

Nitrogen (N) and phosphorus (P) fertilizer recommendations for irrigated onion production is lacking for the different irrigation schemes in the Amhara region, North western Ethiopia. Two different experiments were conducted at Ribb and Kog irrigation schemes to determine the N and P fertilizer levels for irrigated onion. Experiments were conducted in the years 2010 and 2011. Treatments were comprised of factorial combinations of five N levels (50, 100, 150, 200 and 250 kg N ha-1) and three P levels (20, 40 and 60 kg P ha-1) with one satellite control treatment (0/0 N/P) replicated three times in RCBD. Onion variety used was Bombay Red. Results showed that application of 150 kg N ha-1 and 20 kg P ha- at Ribb and application of 100 kg N ha-1 and 60 kg P ha-1 at Koga are best recommended for onion production under irrigation.