Agronomic efficiency, yield and yield components of food barley response to nitrogen rates after fababean in Emba Alaje, Northern Ethiopia

This study was initiated to investigate the effect of nitrogen fertilizer on agronomic efficiency, yield and yield components of barley after faba bean precursor crop.  A field experiment was carried out in 2015 main cropping season at district at Ayba and Tek’a kebeles in Tigray Regional State, Ethiopia. The experiments were arranged in a randomized complete block design with three replications. Treatments were six levels of nitrogen (0, 11.5, 23, 34.5, 46 and 69 kg N ha-1). Soil samples were collected before planting and analyzed for selected physicochemical properties. Pre-planting soil analysis results revealed that total N was low at Tek’a kebelle (0.09%) and medium at Ayba (0.186%). The organic carbon content of experimental fields was medium at Ayba and low at Tek'a. Application of nitrogen had significantly influenced yield and yield components of barley at Tek'a site but not at Ayba after fababean precursor crop. This is consistent with the initial soil nitrogen and contribution of the precursor crop for nitrogen fixation. The highest agronomic efficiency was recorded from the addition of 23 kg N ha-1 (31.52 kg kg-1) and 34.5 kg N ha-1 (31.44 kg kg-1) at Ayba kebelle and Tek’a, respectively. Both biological and partial budget analysis depicted that application of 34.5 kg N ha-1 was found to be economical. Therefore, application of nitrogen after legume crop should consider initial soil result.. Key words: Barley, Fababean, nitrogen, crop rotation, agronomic efficiency.