Response of Onion (Allium cepa L.) Varieties to Blended NPS Fertilizer at Haramaya, eastern Ethiopia

Abstract Onion (Allium cepa L.) is one of the most predominantly produced bulb crops in East Hararghe.The productivity of onion in the study area is mainly below the national average due to a number of production constraints, lack of site specific fertilizer recommendations and improved onion varieties are among others.Therefore, this research was conducted to determine the effect of blended NPS fertilizer rates on yield components, yield and bulb quality of onion varieties at Haramaya, East Hararghe. The experiment was arranged in factorial combination of six rates of NPS fertilizer (0, 50, 100, 150,200, 250 kg ha-1) and three onion varieties (Nasik Red, Sirius F1 and Red coach F1) in a Randomized Complete Block Design with three replications. The analysis of variance revealed that variety and NPS fertilizer had significant effect on onion yield components and bulb yield. The interaction of variety and blended NPS fertilizer showed significant differences on bulb weight, total dry biomass yield, marketable, unmarketable and total bulb yield, TSS and percentage bulb dry matter. The highest bulb weight (219.93 g), bulb dry matter percentage (16.42% ), marketable bulb yield (57.23 t ha-1) and total bulb yield (58.35 t ha-1) were obtained from Red coach F1 at rate of 200 kg ha-1 NPS fertilizer. Thus, production of Red Coach F1 with application of 200 kg ha-1NPS fertilizer could be recommend for onion growers at Haramaya as well as other areas having similar agro-ecologies.