关键词: 西安市, 西安市

Abstract: A field experiment was carried out, for further study on the effect of nitrogen fertilization on nitrogen use efficiency by summer corn and on the accumulation of soil nitrate nitrogen to seek for reasonable amount of nitrogen fertilization to summer corn, with ‘Zhengdan 958’ as the trial material to study the effect of the amount of nitrogen fertilization on nitrogen use efficiency by summer corn and on the change of the accumulation of soil nitrate nitrogen. The results showed that, the yield of summer corn remarkably improves as nitrogen fertilization increased when the fertilizing amount ranges from 0 kg/hm2 to 260 kg/hm2. When the fertilizing amount was above 260 kg/hm2, the yield tends to reduce, and the nitrogen use efficiency by summer corn drops gradually along with the increase of nitrogen fertilization. During the whole process of growth of summer corn, the content of soil nitrate nitrogen showed a tendency of lowering first and then rising slowly. With the increase of nitrogen fertilization, the content of nitrate nitrogen in all soil layers increases correspondingly. Fertilizing appropriate amount of nitrogen could promote nitrogen absorption by summer corn and thereby raise the yield of summer corn. While too much nitrogen would lead to a large quantity of accumulation of nitrate nitrogen in the soil so that the risk of polluting the environment increased. This experiment indicated that, the appropriate amount of nitrogen fertilization into summer corn should be controlled in the range of 195-260 kg/hm2 under the condition of super-high yield cultivation with an overall consideration of corn yield, nitrogen use efficiency and the accumulation of soil nitrate nitrogen.