LAUSR

Water scarcity poses a critical challenge in arid regions of northwest China, where suboptimal irrigation practices have led to significant water resource depletion. This study examines soil water transport mechanisms in maize fields under different irrigation regimes in a representative farming‐pastoral ecotone through field monitoring and HYDRUS‐1D modelling during the 2023 growing season (June–September). The results revealed that, compared with conventional flood irrigation, drip irrigation substantially reduced water loss. The total infiltration amount under drip irrigation was 358 mm, of which 196 mm contributed to deep percolation. The total infiltration amount and deep percolation amount under flood irrigation were 588 and 288 mm, respectively. In contrast, drip irrigation significantly reduced these losses, cutting deep percolation by 39% and improving irrigation water use efficiency by 12%. Furthermore, we identified the optimal groundwater depth for maximizing recharge efficiency. Specifically, the optimal groundwater depths were identified as 1.5 m for drip irrigation and 2.0 m for flood irrigation, yielding irrigation infiltration coefficients of 0.46 and 0.65, respectively. These findings provide a scientific basis for developing efficient irrigation strategies and sustainable groundwater management practices in the water‐limited farming–pastoral ecotones of northern China.