To coordinate the soil inorganic nitrogen release and the maize nitrogen requirement and to heighten nitrogen fertilizer use efficiency, field trial with the maize hybrid Zhengdan 958 (with population of 9 plants/hm\+2) and four treatments (i.e., zero N, sowing N+10 leaf N, sowing N+silking N, and sowing N+milking N, with the rate of 90 kg/hm\+2 at each application time) was carried out at Wuqiao experimental station of CAU in 2002. The results are follows: (1) The nitrate concentration (NC) at 0~200 cm so...