Study Reveals Impact of Salt Crust on Soil Temperature

Soil covered by a salt crust can alter the energy balance within the soil, affecting its temperature. Despite this, the specific effects of salt crust on soil temperature have remained unclear.

In a study published in Agricultural and Forest Meteorology, a research team led by Prof. HAO Xingming from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences, investigated how salt crust influences the temperature of wet sandy soils.

The researchers carried out a laboratory experiment using sandy soil with a shallow groundwater table. They saturated the soil with fresh water and saline solution ( approximately 25%, NaCl), respectively. Salt crust was formed on the soil surface by evaporation, using a halogen lamp. They measured evaporative water loss, the fraction of the surface covered by salt, and temperature changes.

To further understand the effects of the salt crust,  the researchers developed a numerical model that considers variations in cover fraction and thickness of the salt crust, as well as the exothermic enthalpy associated with it. This model simulates the salt crust using boundaries instead of full domains, which allows for a reduction in the number of mesh elements.

The findings indicate that the model effectively describes how soil temperature changes as the salt crust evolves. The study also found that the temperature in saline soil is higher than in salt-free soil. “Saline soil loses less heat than salt-free soil due to the insulating effect of the salt crust,” said LI Xinhu, first author of this study.

This study enhances understanding of energy balance in saline soils and offers new insights into quantitatively describing variations in soil temperature as salt crust develops.

Article link: https://www.sciencedirect.com/science/article/abs/pii/S0168192324004593

Contact

LONG Huaping

Xinjiang Institute of Ecology and Geography

E-mail: longhp@ms.xjb.ac.cn

Web: http://english.egi.cas.cn