Arid Zone Research ›› 2022, Vol. 39 ›› Issue (2): 448-455.doi: 10.13866/j.azr.2022.02.12

• Soil Resources • Previous Articles     Next Articles

Variation in soil salinity and ions in a shallow groundwater area under freeze-thaw

LIU Lei1(),CHEN Junfeng1(),LYU Pengpeng1,ZHAO Dexing1,DU Qi2   

  1. 1. College of Water Resources Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
    2. Taigu Water Balance Experimental Field, Bureau of Hydrology and Water Resources Survey of Shanxi Province, Taigu 030800, Shanxi, China
  • Received:2021-09-22 Revised:2021-11-24 Online:2022-03-15 Published:2022-03-30
  • Contact: Junfeng CHEN E-mail:liulei4525@163.com;chenjunfeng@tyut.edu.cn

Abstract:

In shallow groundwater areas, freeze-thaw is one of the most important factors affecting the soil salinization process. Determining the variation in soil salinity and different soil salinity ions during the freeze-thaw process is of great significance for the prevention and control of soil salinization in seasonal freeze-thaw areas. A ground lysimeter system located on Taigu Water Balance Experimental Field was used to examine soil salinity and soil salinity ions. The ground lysimeter system had six different groundwater depths (0.5, 1.0, 1.5, 2.0, 2.5 m, and 3.0 m) and the soil water content, soluble soil salinity content, and content of soluble soil salinity irons were analyzed during the freeze-thaw period from 2020 to 2021. Correlations between the soil salt content and five salinity ions were analyzed using the Gray correlation method. The results showed that the soluble salinity ions in the soil mainly consisted of Na+, Ca2+, HCO3-, SO42-, and Cl-. The correlation analysis revealed that the soil salt content of soil was highly significantly correlated with Na+ and HCO3-, and significantly correlated with Ca2+ and SO42-. The position of the frozen layer had a strong influence on changes in Na+, HCO3-, SO42-, and soil salt content throughout the freeze-thaw process; however, Ca2+ and Cl- were less affected by the frozen layer. When the entire frozen layer was within the maximum capillary water rise height, salt accumulation in the frozen layer was obvious. However, the frozen layer acted as an obstruction when it was not within the maximum capillary water rise height. There was an inverse relationship between the groundwater depth and soil salt content. When the depth of groundwater was 3.0 m, the change in soil salt content was much lower than that at groundwater depths of 0.5-2.5 m. These results provide a theoretical basis for the prevention and control of soil salinization in shallow groundwater areas.

Key words: freeze-thaw action, groundwater depth, soil salinity, ion content