Response of Maize Varieties with Different Nitrogen Efficiencies to Nitrogen Fertilizer

While pursuing high yields, China’s maize industry is facing a series of complex challenges that not only affect production efficiency but also relate to the sustainable development of the industry. Maize varieties with different nitrogen use efficiencies (NUEs) significantly influence yield. Therefore, investigating the response mechanisms of maize varieties with varying NUEs to nitrogen fertilization can provide theoretical foundations and technical support for achieving high and stable yields, as well as for the breeding of new varieties. Based on previous research findings, this experiment selected three maize varieties with different NUE levels. A field trial was conducted with eight nitrogen fertilization gradient levels to analyze their responses to varying nitrogen inputs, thereby further evaluating the performance of maize varieties with different nitrogen use efficiencies. The results indicated that increasing nitrogen application significantly enhanced maize yield; however, with continued nitrogen application, the yield exhibited a trend of initial increase followed by a decrease or stabilization. The highest yields for Jingpin 450 (JP450), Xianyu 335 (XY335), and Qiule 368 (QL368) were achieved under the N250, N300, and N250 treatments, respectively, reaching 8.9 t·ha−1, 9.2 t·ha−1, and 10.1 t·ha−1. Across all nitrogen treatments, QL368 > XY335 > JP450. Maize varieties with high nitrogen efficiency maintained higher post-anthesis nitrogen accumulation throughout the growth period, thereby promoting the translocation of post-anthesis nitrogen to the grains, increasing grain nitrogen content at maturity, and ultimately improving yield. The dual-high-efficiency maize variety QL 368 (QiuLe 368) achieved high yields under both low- and high-nitrogen conditions, primarily due to its high pre-anthesis nitrogen translocation rate and substantial post-anthesis nitrogen accumulation. This enhanced nitrogen translocation to the grains, improved nitrogen use efficiency, further strengthened the plant’s dry matter production capacity, and ultimately led to high yield and efficiency in maize production.