玉米是干旱区灌溉农业的主要作物之一，研究灌溉水入渗与玉米分层吸水规律对理解玉米农田系统中土壤-植被-大气连续体（SPAC）输水过程尤为重要。以地处干旱气候带的宁夏青铜峡引黄灌区为研究区域，采集了玉米生育期内降水、灌溉水、地下水、玉米茎秆以及1 m内不同深度的7层土壤样品，分析了其δ²H、δ¹⁸O的变化特征，并在氢氧稳定同位素的指示下，结合土壤体积含水率研究了灌溉水进入田间后的入渗过程，进而分别运用直接对比法和贝叶斯混合模型研究了玉米对各层土壤水分的吸收比例和规律。结果表明：（1）青铜峡引黄灌区历次降水、灌溉水、地下水的氢氧同位素呈富集趋势，玉米茎秆水氢氧同位素逐渐贫化；土壤水氢氧同位素在浅层（0~30 cm）富集，浅层以下趋于稳定。（2）灌区大气降水线为δ²H=6.67δ¹⁸O-9，降水受云下二次蒸发作用影响显著，降水和灌溉水进入田间后在土壤表面进行了强烈的蒸发，地下水受降水和灌溉水补给。（3）灌溉水在进入田间后的5 d内迅速下渗，活塞流是灌区内土壤水的主要入渗形式。（4）灌区玉米主要吸收0~30 cm浅层土壤水，整个生育期吸收比例达到44.70%；灌水后玉米的主要吸水层位没有发生变化，浅层贡献比例最大。（5）玉米对土壤水的分层吸收利用与土壤温度、土壤体积含水率密切相关，浅层土壤温度的升高以及由于蒸腾和蒸发作用导致的土壤体积含水率降低，促使玉米增加对中深层土壤水的利用；浅层土壤水分对玉米生长至关重要，干旱情况下需要通过及时灌溉补充玉米主要吸水土壤层水分以保证其正常的生长发育。

Maize is a key crop in irrigated agriculture in arid regions, and understanding the infiltration of irrigation water and stratified water uptake patterns of maize is crucial for studying the soil-plant-atmosphere continuum water transfer processes within maize field systems. This study was conducted in the Qingtongxia Yellow River irrigation district in the arid climatic conditions of Ningxia, China. During the maize growing season, samples of precipitation, irrigation water, groundwater, maize stems, and soil from seven depths within 1 meter were collected. The isotopic variations of δ²H and δ¹⁸O were analyzed. Using the guidance of hydrogen and oxygen stable isotopes combined with soil moisture content analysis, the infiltration process of irrigation water into the field was investigated. The absorption proportions and patterns of maize water uptake from various soil layers were examined using both the direct comparison method and Bayesian mixture models. The results indicate that: (1) The hydrogen and oxygen isotopes of successive precipitation, irrigation water, and groundwater in the Qingtongxia Yellow River irrigation district show an enrichment trend, while those of maize stem water gradually deplete; isotopes of soil water are enriched in the shallow layers (0-30 cm) and stabilize below this depth. (2) The atmospheric precipitation line in the irrigation district is represented by δ²H=6.67δ¹⁸O-9, with precipitation significantly influenced by secondary evaporation under clouds. After entering the field, both precipitation and irrigation water undergo intense surface evaporation, while groundwater is replenished by both. (3) Irrigation water rapidly infiltrates into the field within five days of application, with piston flow as the primary infiltration mechanism in the irrigation district. (4) Maize predominantly absorbs water from the shallow soil layer (0-30 cm), with the absorption proportion reaching 44.70% over the entire growth period; following irrigation, there is no significant change in the main water absorption layer of maize, with the shallow layer contributing the most. (5) The stratified absorption and utilization of soil water by maize are closely correlated with soil temperature and moisture content. The increase in shallow soil temperature and the decrease in soil moisture content due to transpiration and evaporation promote enhanced utilization of water from the middle and deep soil layers. Adequate moisture in the shallow soil layer is crucial for maize growth, and under arid conditions, timely irrigation is necessary to replenish water in the main soil layer to ensure normal growth and development.