To understand the status of soil water and salt and its migration laws during the freezing and thawing period in the farmland shelter forest in the Hetao Irrigation District of Inner Mongolia

the soil moisture

salinity

temperature and related meteorological data were measured and analyzed from October 2020 to April 2021. The results showed that the surface soil temperature changed significantly

and leveled off as the increasing soil depths. The rate of temperature decrease during the freezing period was greater than the rate of temperature rise during the thawing period. Considering the hysteresis of soil temperature changes

the freezing period was about 10 days shorter than the thawing period. Seasonal freezing caused the increased water content in the surface soil

and the dereased soil water content in the deep layer. During the thawing period

the soil water content gradually decreased. The surface soil water content in the farmland edges (0.3 H

4 H) of the forest belts on both sides was smaller than that of farmland (1 H

2 H

3 H). The phenomenon of low soil water content in forest belts gradually disappeared with the deepening of soil layers. There was almost no difference in soil water content at different distances from the forest belt in 100 cm soil layer. During the freezing and thawing period

the salt content in soil increased. Soil freezing caused salt to accumulate in various soil layers. During the thawing

soil salt accumulated to the surface layer

and salt reduced in the deep soil. The degree of soil salt accumulation in farmland near forest belt was stronger than that in far forest belt. The transports of water and salt in soil basically showed a significant correlations

and the variability of salt was greater than that of water

indicating that the process of salt transport was more complicated. The results of this study revealed the law of soil water and salt movement in the farmland within the protection forest during the freezing and thawing period

and could provide a basic theoretical basis for agriculture in the irrigation area.