Arid Zone Research ›› 2022, Vol. 39 ›› Issue (3): 916-923.doi: 10.13866/j.azr.2022.03.25

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Differentiation characteristics and main influencing factors of soil salinization in the West of Hetao Irrigation Area

SU Chunli1,2(),JI Qiannan1,2,TAO Yanzhen1,2,XIE Xianjun1,2,PAN Hongjie3   

  1. 1. School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
    2. National Key Laboratory of Water Pollution Traceability and Control, Wuhan 430074, Hubei, China
    3. Geological Survey Institute of Inner Mongolia, Hohhot 010020, Inner Mongolia, China
  • Received:2021-06-10 Revised:2021-08-07 Online:2022-05-15 Published:2022-05-30

Abstract:

As a result of long-term irrigation from the Yellow River, the Hetao Irrigation Area has experienced extensive soil secondary salinization, which seriously affects the development of the regional economy and ecology. The degree, type, and distribution characteristics of soil salinization in the western Hetao Irrigation Area, and the main factors affecting soil salinization are investigated. Results show that more than 50% of the soil samples in the study area were salinized to varying degrees, which is distributed in patches and blocks. The degree of soil salinization in the north and southeast was serious than that of other parts of the study area, especially in the depressions along the Main canal and Huangji canal. The main types of soil salinity were SO4-Na and SO4·Cl-Na. The average total dissolved solids (TDS) of groundwater in the study area was 2.13 g∙L-1, which is classified as brackish water. The average buried depth of groundwater level is 4.65 m, and 65% of the sampled wells were less than 3 m. High TDS groundwater, which is resulted from long-term flood irrigation and strong evaporation, is the direct cause of soil salinization. The main factors affecting soil salinization in alluvial plains include the elevated salinity of groundwater, shallow groundwater levels caused by agricultural irrigation, and strong evaporation of phreatic water.

Key words: soil salinization, groundwater level, salt content, formation mechanism, flood irrigation, Hetao Irrigation Area