Inadequate water and nitrogen (N) supplies can limit the productivity of maize. Climate change will likely increase drought in many regions on a global scale. The determination of N fertilizer rates under field drought conditions will be critical toward the reduction of agricultural risk. For this study, drought-resistant/sensitive cultivars were selected as experimental samples. Our results revealed that drought stress reduced the relative water content (RWC) of leaves, which resulted in leaf curling, while decreasing photosynthesis levels and N accumulation. In contrast to those without N treatments, the application of N significantly increased grain yields by 26.8% during the wet year but increased only by 5.4% during the dry year. Under the same N levels, the reduction in yield caused by drought increased with the increased application of N. This was because the application of the N fertilizer translated to increase the leaf area and transpiration, exacerbated the soil water loss and induced a leaf curling state in maize, which had deleterious effects on photosynthesis and N absorption. During the dry year, the yields of drought-sensitive cultivars were even less than those without the application of N. Compared with those of drought-sensitive cultivars, the RWCs of drought-resistant cultivars decreased more rapidly, and they entered the state of leaf curling earlier. Thus, N fertilizer inputs should be reduced, and the extent of N fertilization for drought-sensitive cultivars should be reduced even further.

The stay-green leaf phenotype is typically associated with increased yields and improved stress resistance in maize breeding, due to higher nitrogen (N) nutrient levels that prolong greenness. The application of N fertilizer can regulate the N status of plants, and furthermore, impact the photosynthetic rates of leaves at the productive stage; however, N deficiencies and N excesses will reduce maize yields. Consequently, it is necessary to develop N fertilizer management strategies for different types of stay-green maize. For this study, the senescent cultivar Lianchuang 808 (LC808), moderate-stay-green cultivar Zhengdan 958 (ZD958), and over stay-green cultivar Denghai 685 (DH685) were selected as experimental models. Our results revealed that yields of ZD958 were slightly higher than DH685 and notably improved over than LC808. Compared with a non-stay-green cultivar LC808, ZD958 and DH685 still maintained higher chlorophyll contents and cell activities following the silking stage, while efficiently slowing the senescence rate. The supply of N fertilizer significantly prolonged leaf greenness and delayed senescence for ZD958 and DH685; however, the effect was not obvious for LC808. The stem remobilization efficiency of N was higher in the moderate-stay-green cultivar ZD958, in contrast to LC808, while the transfer of leaf N was lower than LC808, which guaranteed high leaf N levels, and that sufficient N was transferred to grains in ZD958. To obtain the highest yields, the optimal N fertilizer rates were 228.1 kg hm⁻² for LC0808, 180 kg hm⁻² for ZD958, and 203.8 kg hm⁻² for DH685. In future, the selection of stay-green type crops might serve as an important agricultural strategy to reduce the quantity of N fertilizer and increase N efficiency.

The Huang–Huai–Hai Plain is a primary wheat production base in China, where lodging remains a critical constraint limiting yield improvement and quality enhancement. Both nitrogen application and wheat varieties are key factors influencing crop lodging resistance. This study aimed to comparatively analyze the differential responses of wheat varieties with distinct gluten properties to nitrogen fertilization gradients and elucidated the physiological mechanisms underlying the nitrogen-mediated regulation of lodging resistance in gluten-type wheat. A two-year field experiment was conducted in Xuchang City, Henan Province, from 2019 to 2021. The experimental design incorporated four varieties of wheat (two medium-gluten wheat varieties, YM49-198 and JM325, and two strong-gluten wheat varieties, XN979 and JM44) and five nitrogen (N) fertilizer levels: 0 kg·ha⁻¹ (N₀), 120 kg·ha⁻¹ (N₁₂₀), 180 kg·ha⁻¹ (N₁₈₀), 240 kg·ha⁻¹ (N₂₄₀), and 360 kg·ha⁻¹ (N₃₆₀). Each treatment was repeated three times, and each plot was completely randomly arranged in the field. An appropriate amount of nitrogen fertilizer significantly increased the wheat yield, with the 240 kg ha⁻¹ treatment achieving maximum yields for YM49-198, JM325, and JM44 from 2020 to 2021, but not for XN979. Quality parameters were significantly affected by varieties and nitrogen fertilizer levels. The results showed that the crude protein contents of XN979 and JM44 were 15.13% and 18.06%, respectively, under the N₂₄₀ treatment; the lodging resistance index of the medium-gluten wheat was higher than that of the strong-gluten wheat. Under the N₂₄₀ treatment in 2020–2021, the lodging resistance indexes of YM49-198, JM325, XN979, and JM44 were 12.2, 13.9, 7.9, and 11.7, respectively. Nitrogen fertilizer can increase wheat yield and ensure quality, but excessive application can decrease these factors and intensify lodging risk. The lodging index of the medium-gluten wheat was more sensitive to the amount of nitrogen fertilizer. When the nitrogen application is 240 kg·ha⁻¹, the quality indicators of medium- and strong-gluten wheat should meet standards, and the yield will be stable in the Huang–Huai–Hai Plain. These findings highlight the importance of adopting precision nitrogen management strategies and gluten-type-specific cultivation practices in wheat production systems. This could effectively balance yield stability, quality optimization, and lodging risk mitigation to ensure the sustainable intensification of wheat cultivation in the Huang–Huai–Hai Plain and similar agro-ecological regions.