Work

Single spring irrigation with optimized nitrogen sustains winter wheat yield and improves water productivity and profitability in the North China Plain

Year: 2026

Type: article

Abstract: Optimizing irrigation and nitrogen (N) management is critical for sustainable winter wheat production in the North China Plain (NCP). To clarify the optimal N rate under a single spring irrigation regime, a split-plot field experiment (2020–2023) compared two irrigation schedules—W2: 75 mm at the spring 3-leaf stage and again at anthesis; W1: a single 75 mm irrigation at the spring 4-leaf stage—crossed with four N rates (N1–N4: 180, 240, 300, 360 kg N ha -1 ). Relative to W2, W1 reduced evapotranspiration, increased soil water consumption, and redistributed water use toward the jointing–anthesis stage. However, W1 incurred a 3.3–11.6% yield penalty compared with W2. Under W1, applying 300 kg N ha -1 (N3) maximized spike number and flag-leaf area, lowered canopy temperature, maintained flag-leaf photosynthetic capacity, increased dry matter accumulation and harvest index, and consequently produced the highest grain yield (8,351.5 kg ha -1 ). The W1N3 combination achieved the greatest crop water productivity (2.1 kg m -3 ), irrigation water productivity (11.1 kg m -3 ), agronomic N efficiency (11.2 kg kg -1 ), net income, and benefit-cost ratio. Quadratic response modeling indicated that, under W1, an N range of ≈279–298 kg ha -1 attains 95–100% of the maximum yield and net income. These results provide actionable guidance for water-saving wheat cultivation in the NCP: single spring irrigation at the 4-leaf stage paired with ∼280–300 kg N ha -1 can largely offset yield penalties while improving resource-use efficiency and farm profitability.

Source: Journal of Agriculture and Food Research

DOI: 10.1016/j.jafr.2026.102738