Abstract:

Legume green manure incorporation offers a potential pathway for sustainable croppingin arid irrigated areas. This study aimed to determine whether water and nitrogen inputscould be concurrently reduced without compromising maize productivity under this prac-tice. A two-year field experiment (2024-2025) was conducted using a split-plot designwith three irrigation levels (I1: 4045, I2: 3240, I3: 2430 m3.ha-1) and three nitrogen rates(N1: 360, N2: 288, N3: 216 kg ha-1). Compared with conventional management (I11N1),20% co-reduction in water and nitrogen (I2N2) maintained stable leaf area index (LAI), netphotosynthetic rate (Pn), transpiration rate (Tr), DM, and GY, while significantly increasingwater use efficiency (WUE) by 7.6% and nitrogen use efficiency for grain yield (NUtEg)by 11.7%. Excessive water reduction (13) or nitrogen reduction (N3) significantly inhibitedgrowth and reduced yield (p < 0.05). Soil water content under I2N2 did not differ signifi-cantly from I1N1 in the 0-110 cm profile, and soil total nitrogen remained higher at silking.)Structural equation model (SEM) revealed SWC and STN indirectly affected Pn and Tr viaregulating LAI and SPAD (path coefficients: 0.48-0.62), which drove DM accumulation anddetermined GY (R2 = 0.81). These short-term results suggest that moderate water-nitrogenreduction with green manure can sustain yield while improving resource efficiency, offer-ing a promising practice for arid irrigated maize systems, though longer-term validationis needed.