Objectives Exploring the response characteristics of spring wheat cultivars with different drought resistant capacities to deficit irrigation during the growth period, to provide technical support for optimizing water and fertilizer management of spring wheat in Xinjiang.

Methods In 2022 and 2023, pipe and field planting experiments, with the split zone design, were conducted at the Agricultural College Experimental Station of Shihezi University. The main factor was cultivar, including a drought sensitive cultivar Xinchun22 (XC22) and drought resistant cultivar Xinchun6 (XC6). The sub-factor was deficit irrigation period, including a full irrigation control (75%−80% of field water capacity) throughout the entire growth period (CK); a mild deficit irrigation (T1, 60%−65% FC), and a moderate deficit irrigation (T2, 45%−50% FC) during tillering stage, and mild and moderate deficit irrigation during jointing stage (J1, and J2), respectively. At initial and after flowering stage, plant samples were collected for the determination of dry matter and nitrogen content of various organs, and at maturing stage the yield and yield components were investigated. Then the pre-anthesis N accumulation and export, post-anthesis N accumulation, and nitrogen fertilizer use efficiency were calculated.

Results The N accumulation (166.15−238.87 kg/hm²), vegetative organ N allocation rate, pre-anthesis N export (21.76−57.66 kg/hm²) and its contribution to grain (14.15%−31.66%), pre-anthesis total nitrogen export (78.67−147.66 kg/hm²) and contribution rate (51.58%−81.11%) of the two wheat cultivars were all lower in the T2 and J2 treatments than in T1 and J1, while the grain N allocation rate, post-flowering N absorption and contribution rate of plants were higher in the T2 and J2 treatments than in T1 and J1. Under deficit irrigation treatment T1 and J1, XC6 was recorded higher pre-anthesis N accumulation, export and contribution rate in various organs, and yield and yield components than XC22. For XC6, compared with CK, T1 treatment significantly increased the pre-anthesis N export and contribution rates by 24.06% and 18.91% in stems and sheaths, and by 19.21% and 12.53% in whole plants, thereby enhanced maturing plant N accumulation by 9.98% and yield by 12.17%, and elevated N use efficiency, fertilizer N production efficiency, and N harvest index by 2.25%, 12.16%, and 3.71%.

Conclusions For drought resistant spring wheat cultivar, mild deficit irrigation at tillering stage (60%−65% FC) is suitable for the accumulation and transportation of nitrogen at pre-anthesis stage, so could improve nitrogen absorption and nitrogen harvest index, and effectively increase yield, and achieve water-saving and high-yield effects. However, deficit irrigation is not suitable for the yield and nitrogen use efficiency of drought sensitive wheat cultivar, regardless drought stress period and intensity.