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Arid Land Geography ›› 2024, Vol. 47 ›› Issue (11): 1899-1914.doi: 10.12118/j.issn.1000-6060.2023.667

• Climatology and Hydrology • Previous Articles     Next Articles

Water infiltration and maize root water uptake patterns in the Qingtongxia Yellow River irrigation district

MA Guorong1(), ZHUANG Haoran1, XU Dehao1, MA Yongcheng1, ZHAO Mengyang1, FENG Kepeng1,2,3()   

  1. 1. School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, Ningxia, China
    2. Key Laboratory of the Internet of Water and Digital Water Governance of the Yellow River in Ningxia, Yinchuan 750021, Ningxia, China
    3. Ningxia Engineering Research Center for Water-Saving Irrigation and Water Resources Control, Yinchuan 750021, Ningxia, China
  • Received:2023-11-24 Revised:2024-03-11 Online:2024-11-25 Published:2024-12-03
  • Contact: FENG Kepeng E-mail:mgr1005@163.com;fengkp@nxu.edu.cn

Abstract:

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.

Key words: stable isotope, irrigation water infiltration, direct contrast method, MixSIAR model, root water absorption changes, atmospheric precipitation line