In the face of declining water resources and climatic variability, growth stage‐based deficit irrigation may be a feasible approach to enhance agricultural system resilience. A 3‐yr experiment was conducted to evaluate the impact of deficit irrigation on maize (Zea mays L.) in the late vegetative (Lveg) and maturation (Mat) growth stages, where phenology, dry leaf weight, aboveground biomass, yield, kernel number, 1000 kernel weight, and grain‐filling rate were evaluated. Water deficit during the Lveg stage decreased the kernel number and dry leaf weight, thus decreasing the potential grain‐filling rate (less photosynthetic tissue). In contrast with deficit during the Lveg stage, deficit during the Mat stage directly reduced the grain‐filling rate and duration and thus had the strongest effect on grain yield. A growth stage interaction was evident, such that the reduction in yield associated with water deficit applied during the Lveg stage was exacerbated by water deficit applied during the Mat stage. Yield reduction was proportional with the severity of the water deficit, in all cases. Nevertheless, water deficit applied during the Mat stage had a larger impact on maize yield compared with water deficit applied during the Lveg stage. If farmers have reduced water allocations but seasonal flexibility in the timing of irrigation water application, they will maximize yield by saving water for reproductive and maturation growth stages.Core Ideas Water deficit during the late vegetative stage decreased the kernel number and dry leaf weight. Deficit applied during the maturation stage directly reduced the grain‐filling rate. Yield reduction was proportional with the severity of the water deficit. Water deficit during the maturation stage had a larger impact on maize yield compared with that at the late vegetative stage.

Water scarcity is the most critical constraint for sustainable cotton production in Xinjiang Province, northwest China. Drip irrigation under mulch is a major water-saving irrigation method that has been widely practiced for cotton production in Xinjiang. The performance of such an irrigation system should be evaluated for proper design and management. Therefore, a field experiment and a simulation study were conducted to (1) determine a modeling approach that can be applied to manage drip irrigation under mulch for cotton production in this region; and (2) examine the effects of irrigation amount and mulch on soil water distribution and root zone water balance components. In the experiment, four irrigation treatments were used: T1, 166.5 m³; T2, 140.4 m³; T3, 115.4 m³; and T4: 102.3 m³. The HYDRUS-2D model was calibrated, validated, and applied with the data obtained in this experiment. Soil water balance in the 0–70 cm soil profile was simulated. Results indicate that the observed soil water content and the simulated results obtained with HYDRUS-2D are in good agreement. The radius of the wetting pattern, root water uptake, and evaporation decreased as the amount of irrigation was reduced from T1 to T4, while a lot of stored soil water in the root zone was utilized and a huge amount of water was recharged from the layer below 70 cm to compensate for the decrease in irrigation amount. Mulch significantly reduced evaporation by 11.7 mm and increased root water uptake by 11.2 mm. Our simulation study suggests that this model can be applied to provide assistance in designing drip irrigation systems and developing irrigation strategies.