Water management is critical for wheat production under extreme drought conditions, and the mechanisms by which root dynamics and soil water utilization affect wheat yield are uncertain. This study was conducted in 2023–2024 under a mesophilic semi-arid climate with a two-factor partitioned experimental design, aiming to assess the response of different irrigation amounts in winter wheat crops on root growth and development, soil water utilization, and yields in different soil horizons. The results showed that variety and irrigation volume had significant effects on the spatial and temporal distribution of root and yield components, with irrigation volume having the greatest effect on yield. Compared with CK, deficit-regulated irrigation significantly promoted root penetration to deeper layers and delayed root senescence. DRWD, RLD, RSA, and RV decreased gradually with increasing soil depth, and the peaks of RLD, RSA, and RV appeared at the tassel to flowering stage, respectively; and under deficit-regulated irrigation, the contribution of the A2W4 treatment to stable yield was greater. Therefore, A2W4 is an effective water-saving irrigation method to improve grain yield and water-use efficiency under deficit-regulated irrigation.

The present study was conducted at the Xinjiang Qitai Wheat Experiment Station from 2023 to 2024 with the objective of assessing the effects of different irrigation levels on the yield and water use efficiency of drip-irrigated winter wheat under deficit-regulated irrigation conditions. A two-factor splitzone group design was employed to evaluate the responses of New Winter 22 (A1) and New Winter 18 (A2) varieties under six distinct irrigation levels. The results demonstrated a distinctive trend in the leaf area index (LAI), relative chlorophyll content (SPAD), and soil water content within the 0-80 cm layer, exhibiting an initial increase followed by a decline throughout the crop's lifespan. As the irrigation frequency was reduced, the total volume of water consumed and the yield-related indices declined. Conversely, water use efficiency demonstrated an "N"-shaped growth trajectory, reaching its maximum value at a specific point. Notably, the highest yield of 7100.04 kg ha-1 was observed in the W5 treatment group. Accordingly, the A2 variety, irrigated by drip at a rate of 3360-4440 m³ ha-1, proved to be the optimal combination of varietal water volume under the conditions of this experiment.