ABSTRACT Quantifying crop evapotranspiration (ET c ) dynamics and their partitioning into soil evaporation (E) and plant transpiration (T) is crucial for improving water productivity and developing precise irrigation strategies. However, the spatiotemporal distribution of soil moisture and its influence on ET c partitioning in drip‐irrigated maize fields are poorly understood. This study investigated soil water dynamics, leaf area index (LAI), ET c and its components under varying irrigation lower limits (W1: 50%–60% FC, W2: 65%–75% FC, W3: 80%–90% FC, where FC was the soil field capacity) during different maize growth stages in 2023 and 2024. The results indicated that as the irrigation amount increased, the vertical advance depth of the soil wetting front increased more significantly than the surface wetting radius Maize growth was suppressed at the tasselling stage under W1. T/ET c showed a quadratic relationship with ET c ( R 2 = 0.50) when reference evapotranspiration (ET 0 ) exceeded 1.9 mm d −1 , with an inflexion point at ET c = 6.1 mm d −1 . T/ET c correlated strongly with LAI through a logarithmic function ( R 2 = 0.95), especially at early growth stages. Soil water content (SWC) demand peaked at the tasselling stage. An irrigation strategy that maintains higher soil moisture (e.g., W3: 80%–90% FC) during the water‐sensitive tasselling and seedling stages, while applying mild deficit irrigation (e.g., W2: 65%–75% FC) during the jointing and filling‐to‐maturity stages, can optimize the T/ET c ratio and achieve synergistic improvements in grain yield (GY) and water productivity (WP). This study enhanced the understanding of soil water's role in ET c partitioning in drip‐irrigated maize, providing a quantitative basis for optimizing irrigation scheduling to enhance both GY and WP.
Wang et al. (Sun,) studied this question.