Abstract: A field experiment was conducted to investigate the effects of fertilization methods, i.e., drip (DF) and furrow fertilization (GF), and nitrogen (N) application rates (25, 50, 75 g N·plant^-1·time^-1) on the dynamics of soil N vertical migration in a Populus ×euramericana cv. ‘Guariento’ plantation. The results showed that soil NH₄⁺-N and NO₃^--N contents decreased with the increasing soil depth under different fertilization methods and N application rates. In the DF treatment, soil NH₄⁺-N and NO₃^--N were mainly concentrated in the 0-40 cm soil layer, and their contents ascended firstly and then descended, reaching their maximum values at the 5th day (211.1 mg·kg^-1) and 10th day (128.8 mg·kg^-1) after fertilization, respectively. In the GF treatment, soil NH₄⁺-N and NO₃^--N were mainly concentrated in the 0-20 cm layer, and the content of soil NO₃^--N rose gradually and reached its maximum at the 20th day (175.7 mg·kg^-1) after fertilization, while the NH₄⁺-N content did not change significantly after fertilization. Overall, N fertilizer had an effect within 20 days in the DF treatment, and more than 20 days in the GF treatment. In the DF treatment, the content and migration depth of soil NH₄⁺-N and NO₃^--N increased with the N application rate. In the GF treatment, the NO₃^--N content increased with the N application rate, but the NH₄⁺-N content was not influenced. Under the DF treatment, the hydrolysis rate, nitrification rate and migration depth of urea were higher or larger than that under the GF treatment, and more N accumulated in deep soil as the N application rate increased. Considering the distribution characteristics of fine roots and soil N, DF would be a better fertilization method in P. ×euramericana cv. ‘Guariento’ plantation, since it could supply N to larger distribution area of fine roots. When the N application rate was 50 g·tree^-1each time,  nitrogen  mainly distributed in the zone of fine roots and had no   risk of deep leaching, consequently improving the fertilizer utilization efficiency.