A two-year field experiment was conducted to investigate the effects of traditional fertilization (T1) and optimized fertilization (T2, T3) on summer maize yield and nitrogen use efficiency (NUE). A no-nitrogen application treatment (CK) was used as the control. The results showed that optimized fertilization (T2, T3) increased yield by 8.5% and 12.1% and enhanced nitrogen fertilizer utilization efficiency by 58.8% and 64.7%, respectively, when compared to traditional fertilization. However, no significant differences in yield were observed between the the T2 and T3 fertilization methods. Summer maize growth was constrained by limited accumulated temperature during the growing season. However, sufficient light and heat resources were available in the early growth stage, leading to rapid development. Conversely, the later growth stage was characterized by low temperatures, reduced sunlight, and frequent rainfall, resulting in slower development. Therefore, production management should prioritize early growth by enhancing water and nutrient supply to ensure robust seedlings and a high-yield population. The T2 fertilization scheme is recommended for general farmland, while T3 fertilization scheme is more suitable for achieving ultra-high-yield fields. |