Abstract:【Objective】Wuchang and Changshu are the representative production areas of high-quality japonica single-cropping rice in Northeast and East of China, respectively. However, the amount of nitrogen (N) fertilizer required to maintain a high yield in Wuchang is usually much lower than that in Changshu, but the agronomic use efficiency of fertilizer N (AE) is higher than that in Changshu. Different hydrothermal conditions, crop varieties, farmland managements and soil types in these two places make it difficult to identify what causes such regional differences. To explore soil factors' influence on NUE, black paddy soil (BS) and gleyed paddy soil (WS) were collected from the two rice fields. 【Method】There were three N treatments as follows: no N treatment (CK), low N rate and high N rate (N 150 and 300 kg·hm–2 with 15N urea). A rice pot experiment was carried out in Changshu National Agro-Ecosystem Observation and Research Station to compare the rice yield, NUE, and total N loss between the two soils. The characteristics of N mineralization in the two paddy soils were also studied through a three-week indoor anaerobic incubation experiment. 【Result】The results suggested that the rice yield, agronomic fertilizer N use efficiency and above-ground N uptake of BS were better than that of WS among these N treatments under the same climate, rice variety and management levels. The NUE of BS was higher than that of WS by about 20.0%-28.7%. However, the 15N recovery efficiency of BS was only higher than that of WS by about 5.56%-8.01%. Although the above-ground N uptake by rice increased after N addition in two soils, the N increment of BS from the soil source was 95%-215% higher than that of WS. Also, the increment of N taken up from the priming effect (difference of above-ground plant N uptake derived from the soil between CK and the corresponding N application treatments) of BS was 173-354 mg·pot–1 and 88-113 mg·pot–1for WS. This observation was consistent with the results that the soil N mineralization amount of BS was 0.95-2.49 times higher than that of WS after N application in the anaerobic incubation experiment. Thus, this result indicated that the N application had a greater priming effect on the increase of N supply in BS soil. Also, the total loss of 15N fertilizer in WS soil was significantly higher than that of BS with the increase of N application rate in the pot experiment. 【Conclusion】Overall, the high yield and NUE of BS may be related to the fact that N fertilizer could provide a greater priming effect and maintain a higher soil N retention level. However, the rice yield of WS depended more on the N fertilizer input due to its lower priming effect of N fertilizer and had a weaker ability to retain fertilizer N. Thus, the soil is an important factor influencing the difference in agronomic use efficiency of fertilizer N and N use efficiency in paddy fields.