Effect of nitrogen fertilizer on grain yield,quality and water use efficiency of corn in dryland of Loess Plateau

Nitrogen fertilizers of plastic-film corn were conducted at Zhenyuan Dryland Experiment Base during 2002─2003.The results showed that the impact of nitrogen fertilizer on corn yield presented a highly significantly difference between different years,but there was no stataistically difference in grain yield difference between various types of corn in same year or same cultivated corn in different years.The yield increased with nitrogen application rates,and grain yield increase from one per kg N,water use efficiency and photosynthetic rate(Pn) were obtained when N was applied at a rate of 180 kg/ha.However,fat,protein and starch content in corn were improved with nitrogen application rate increase till 180 kg/ha.In addition,water stress was in favor of volume weight increase and the accumulation of protein and starch.