Optimizing nitrogen rate under single irrigation can maintained a high yield and increased economic benefits in winter wheat

Abstract

Aims Optimizing winter wheat irrigation and nitrogen fertilizer management is crucial for ensuring sustainable agricultural development in North China Plain (NCP). However, the optimal nitrogen management, especially in single irrigation in spring for winter wheat, is not clear. Methods In 2020–2022, we conducted a field experiment to explore the effects of different irrigation levels (W2, irrigated of 75 mm at the spring 3-leaf stage and anthesis stage, respectively; W1, irrigated of 75 mm at spring 4-leaf stage) and nitrogen levels (180, 240, 300 and 360 kg N ha^− 1; denoted as N1, N2, N3 and N4, respectively) on grain yield, water consumption and economic efficiency. Results The findings demonstrated that W1 reduced evapotranspiration, increased soil water consumption and enhanced water consumption from jointing to anthesis stage. However, W1 irrigation resulted 3.3–11.6% yield loss compared to W2. Adjusting nitrogen fertilizer inputs (300 kg N ha^− 1) under W1 can achieves high spike number, flag leaf photosynthetic capacity and harvest index, ultimately resulted in a highest grain yield (8351.5 kg ha^− 1). Additionally, W1N3 obtained the highest water use efficiency (20.5 kg ha^− 1 mm^− 1), irrigation water use efficiency (111.4 kg ha^− 1 mm^− 1), nitrogen agronomic efficiency (11.2 kg kg^− 1), net income and benefit-cost ratio. Based on the water and nitrogen inputs to the yield and economic efficiency model, applying N at 278.8–297.8 kg ha^− 1 under W1 conditions achieved 95–100% of the maximum yield and net income. Conclusions These results may provide a scientific foundation for optimizing irrigation and nitrogen management and enhancing local farmers’ economic efficiency.