The effects of soil freeze–thaw processes on water and salt migrations in the western Songnen Plain, China

Abstract

Seasonally freeze-thaw (FT) processes affect soil salinisation in cold and arid regions. Therefore, understanding the mechanisms behind soil salinisation during winter and spring is crucial for management strategies effectively alleviating this. This study aimed to explore the soil FT characteristics and their influences on soil water and salt migrations to clarify the underlying mechanism of the springtime soil salinisation in the western Songnen Plain, China. The spatiotemporal distributions of soil water and salt, frozen depths and soil temperatures were examined at depths of 0–200 cm in three typical landscapes (farmland, Leymus chinensis (Trin.) Tzvel (LT) grassland and alkali-spot (AS) land) from October 2015 to June 2016. Results indicated that the strongest freezing process occurred in AS land, which was characterised by the deepest frost depth (165 cm) and highest freezing rate (3.58 cm/d), followed by LT grassland, and then farmland. The freeze-induced upward redistribution and enrichment of soil water and salt caused the rise and expansion of the soil salification layer, which was the main source of explosive accumulations of surface salt in springtime. Therefore, the FT processes contributed to the surface soil salinisation and alkalisation. Landscapes also affected soil water and salt migrations during FT processes, with the trend being AS land > LT grassland > farmland.

Study on the factors affecting cracking of earthen soil under dry shrinkage and freeze–thaw conditions

“…Under the dry shrinkage condition, the water in the earthen site continuously migrates to the surface and evaporates into the atmosphere. Under the conditions of freezing and thawing, the earthen site’s surface water crystallizes in the intergranular pores 29 , forming a frozen surface. When the water migrates to a certain extent, it forms ice rimming.…”

Investigation of Water and Soil Migration and Mud Pumping of Subgrades under Traffic Load

“…Meanwhile, due to the infiltration of atmospheric precipitation and the difficulty of drainage for fine soils, the water content in the subgrade increases. The subgrade is subjected to frequent dynamic traffic loading and erosion by rising groundwater levels, the soil in the subgrade is prone to dispersion, and problems such as mud pumping of the existing railway subgrade occur frequently [8][9][10][11][12][13][14]. Therefore, indepth research is urgently needed on the relationship between water migration and fine soil migration under traffic load [15,16], and to clarify the process of water and soil migration.…”

On the extinction depth of freezing-induced groundwater migration

“…Freezinginduced groundwater migration and the resulting water table recession have been observed in many countries like the US (Daniel and Staricka, 2000;Drescher, 1955;Meyer, 1960;Schneider, 1961), Canada (Ireson et al, 2013;Pan et al, 2017;van der Kamp et al, 2003), Sweden (Stähli et al, 1999), Russia (Vinnikov et al, 1996) and China (Lyu et al, 2022;Yi et al, 2014;Wu et al, 2016;Zhang et al, 2019). Moreover, by transporting water and dissolved ions from groundwater to seasonally frozen soils, freezing-induced groundwater migration would strengthen the possibilities of frost heave (Chamberlain, 1981;Bronfenbrener and Bronfenbrener, 2010;Rui et al, 2019) and soil salinization (Qin et al, 2021;Wang et al, 2022). Nevertheless, there is still limited quantitative understanding of the conditions that groundwater can be migrated to seasonally frozen soils.…”