Response of nitrogen use efficiency and agronomic characteristics of winter wheat to rate, time and method of nitrogen application

In order to evaluate of nitrogen use efficiency and agronomic characteristics of winter wheat to rate, time and method of nitrogen application, this study was carried out in the field of Payaam Nour Arak University in Markazi province in 2011. A factorial arrangement of treatment in a randomized complete block design with three replications was used. Factors were included 1- time of nitrogen application (T1= 50% of nitrogen in sowing date + 50% of nitrogen in tillering stage, T2= 50% of nitrogen in tillering stage + 50% of nitrogen in stem elongation, T3= 50% of nitrogen in stem elongation + 50% of nitrogen in heading stage), 2- rate of nitrogen application (R1= 150 kg ha-1 urea, R2= 300 kg ha-1 urea) and 3- method of nitrogen application (M1= mix with soil, M2= using by irrigation, M3= foliar application). Each plot consisted of 4 rows, 5 m long. Results indicated that the using time affected on the characteristics such as: stem height, peduncle and spike length, number of spike per m-2, number of grain per m-2, spike biological yield, economical yield of spike, and nitrogen use efficiency significantly. The effect of nitrogen rate was significant on stem height, peduncle and spike length, number of grain per m-2, spike biological yield and nitrogen use efficiency, too. Results indicated that the nitrogen use efficiency was significantly higher than of other treatments in foliar application of urea fertilizer (150.4 %) and using nitrogen by irrigation (14.07 %).