Abstract

An offseason field experiment was conducted in 2015-2016 at Werer Agricultural Research Center Middle Awash, Afar regional state to determine N-uptake and use efficiency of irrigated bread wheat (Triticum aestivum L.) as influenced by seed and nitrogen fertilizer rates. The experiment was laid down in a randomized complete block design (RCBD) with three replications. The treatments were factorial combination of five nitrogen levels (0, 23, 46, 69, and 92 kgNha^-1) with four seed rates (75, 100, 125, and 150 kgha^-1). The results of the study showed that both main and interaction effect of nitrogen and seed rates significantly affect N concentrations of the grain and straw, N-uptake, apparent nitrogen recovery, agronomic and physiological efficiencies, nitrogen use efficiency, grain protein content, and N harvest index. The apparent recovery, agronomic and physiological efficiencies and nitrogen use efficiencies decreased with increasing N-rate. Concentration of N and total nitrogen uptake in straw and grain, grain protein and NHI were increased as the N rate increased, while decreased with the increment of seed rate. In conclusion, rate of nitrogen fertilizer applied and seed rate affect the N-uptake and N-use efficiencies.

Keywords: Seed rate; Nitrogen rate; Nitrogen uptake; Nitrogen use efficiency; Wheat