| Cite this article: | 毛 俊,伍靖伟,刘雅文,等.盐分对季节性冻融土壤蒸发影响的试验及数值模拟研究[J].灌溉排水学报,0,():-. |
| Mao Jun,Wu Jingwei,Liu Yawen,et al.盐分对季节性冻融土壤蒸发影响的试验及数值模拟研究[J].灌溉排水学报,0,():-. |
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| Experimental and numerical simulation study on the salt effects on the evaporation from freezing/thawing soil |
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Mao Jun1, Wu Jingwei1, Liu Yawen1, Wu Mousong2
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1.State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University;2.International Institute for Earth System Science
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| Abstract: |
| Abstract: 【Background】Seasonal frozen soil is widely distributed in our country as an important land resource. With the growth of population, it’s necessary to develop and utilize the seasonal frozen soil. Hetao Irrigation District is one of the three major irrigation areas and a typical seasonal frozen area, which is located in an arid and semi-arid region in Inner Mongolia, China. However, it is often threatened by soil salinization and water shortage, which are the main factors that constrain the sustainable development of agriculture in China. Soil evaporation as a significant part of surface energy and water balance in seasonal frozen regions, it plays an important role in water management and formulation. In order to control soil salinization and save water resource, it is of great significance to calculate soil evaporation from freezing/thawing soil accurately. However, soil evaporation is affected by salt content. Therefore, it’s necessary to calculate soil evaporation considering salt effects.【Objective】The purpose of this paper is to evaluate the impacts to evaporation from freezing/thawing soil with different salt contents.【Method】The soil columns with different salt contents of B1 and B2（B1：7.80 g/kg；B2：41.16 g/kg） experiments were conducted in Inner Mongolia, China, and its process of soil evaporation with various salt contents was observed and analyzed during different freezing/thawing period. Based on that, a numerical evaporation model considering the salt effects reflected by salt impedance and soil surface impedance was developed, and it was calibrated/validated by the experimental observations and compared with SHAW model. Then, the numerical model was used to simulate the evaporation processes from freezing/thawing soil under 9 various salt contents（S1-S9：0, 2.5, 5, 7.5, 10, 15, 20, 35, 50 g/kg）.【Result】The difference in evaporation rate with various salt contents is notable, especially in the beginning freezing period and thawed period, the average evaporation rate of B1 soil column with low salt content is 1.5 times and 1.8 times of that of B2 soil column, respectively. Compared with SHAW model, the established numerical model in this study is able to simulate evaporation process reasonably well and more suitable for seasonal frozen soil affected by salinization. The evaporation from freezing/thawing soil increases first and then decreases with the increase of salt content, and when the salt content is S6（15 g/kg）, the soil evaporation is the largest reaching 136.3 mm; Compared with S1 of salt free, soil evaporation of S2-S6 increase by 1.09%、13.68%、56.22%、73.73% and 86.46%, respectively, while compared with S6, that of S7-S9 decrease by 10.20%、26.34% and 42.55%, respectively.【Conclusion】Salt has a great significant impact on the evaporation of seasonal freezing/thawing soil, and its effect is to promote evaporation first and the inhibit. The established numerical evaporation model considering salt effects can improve the accuracy of evaporation from saline farmland. This study helps to understand the mechanism of soil evaporation under salt effects in seasonal freezing regions and provide a useful tool for simulating soil and water movement in such region. |
| Key words: Salt; Freezing-thawing soil; Evaporation rate; Numerical simulation. |
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