Response of Maize Yield Components to Growth Stage-Based Deficit Irrigation

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.