Abstract:The 15N-label technique was employed in the maize field to quantify the nitrogen fertilizer utilization and its fate.The experiment was designed with three nitrogen fertilizer application rates (0, 120, 240 kg/hm2), and three replications were set up in each treatment. Results showed that soil residual 15N increased significantly with the increasing of nitrogen fertilizer application (P<0.05). For the spatial distribution, soil residual 15N showed a trend of decreasing first and then rising, and the accumulation of 15N in 40-60 cm and 60-80 cm soil layers were the maximum in both high nitrogen treatment (240 kg/hm2) and low nitrogen treatment (120 kg/hm2), and the residual 15N in these two soil layers accounted for 37.55% and 18.99% of the total input amount, respectively. Compared with the control, application of nitrogen fertilizer significantly improved the dry matter, grain yield and total nitrogen uptake rate of different parts of maize. Although the nitrogen application rate of high nitrogen treatment increased by 1 times compared with the low nitrogen treatment, the grain yield increased only 0.14 times. The agronomic efficiency and the apparent utilization rate of nitrogen fertilizer decreased significantly with the increasing of nitrogen application rate. The utilization rates of nitrogen fertilizer labeled by 15N, the soil nitrogen residual rates, the proportion of leaching loss into groundwater and the other loss rates were 28.86%, 50.42%, 4.27% and 16.45% in the high nitrogen treatment, respectively, while these values of low nitrogen treatment were 31.15%, 36.52%, 0.68% and 32.33%, respectively. All these results showed that the nitrogen application of 120 kg/hm2 would be favorable to improve grain yield and nitrogen use efficiency, and reduce residual nitrogen rate in soil. Therefore, this nitrogen application rate was suggested to lighten the environment pollution risk.