Abstract: A field experiment was carried out in order to identify the effect of rates and time of nitrogen application on grain yield of winter wheat and soil NO³_--N content of 2 m profile during growing stage. The experiment was conducted at the Wuqiao Experiment Station of China Agriculture University, Cangzhou city, Hebei province, China. The mean rainfall was 562 mm for past 10 years, and it was 69.5 mm (2004/2005) during the growth period of winter wheat. The results showed that: the grain yield ranged from 7350 to 7815 kg/ha, yield of application N treatment were higher than N0. The nitrogen physiological efficiency significantly decrease at 0.05 level with the rates of nitrogen application increasing. The soil NO³_--N content of application N treatments at anthesis and harvest were significantly higher than N0. At the same time, soil NO³_--N content in 0-60 cm profile increase with the rates of nitrogen application at jointing, anthesis and harvest, respectively. The soil NO³_--N content at anthesis were highest during growing stages. The soil NO³_--N content in 20-60 cm profile of two split N application was higher than basal N application of 157.5 and 226.5 kg/ha at harvest (N88.5+69>N157.5, N123+103.5>N226.5), respectively. The accumulation of soil NO³_--N residue of 2 m profile at harvest significantly increase with the rates of nitrogen application, and the accumulation of soil NO³_--N of two split application were higher than of basal application under same nitrogen rates.

Key words: Nitrogen application rate, Winter wheat, Yield, NO³_--N

CLC Number: 

• S143.1