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| DOI：10.13522/j.cnki.ggps.2025098 |
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| Salt leaching, water-salt transport and desalination in coastal saline-alkali soil under subsurface drain drainage |
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ZHU Yuduo, WANG Wei, HUANG Qian, WANG Jinlong, PANG Guibin
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1. School of Water Conservancy and Environment, Jinan University, Jinan 250022, China;
2. Shandong Provincial Institute of Water Conservancy Science, Jinan 250013, China;
3. Shandong Key Laboratory of Water Network Dispatching and Efficient Utilization, Jinan 250013, China
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| Abstract: |
| 【Objective】Coastal saline-alkali soils could cause severe damage to crop and reduce agricultural production. To understand the mechanisms underlying salt movement and develop mitigating strategies, we investigate water and salt movement, as well as the associated desalination in such soils under subsurface drain drainage. 【Method】 The experiment was conducted in soil columns. Saline -alkali soils taken from the Kenli District; Dongying City was used in the experiment. During the experiment, we measured the spatiotemporal dynamics of soil water, electrical conductivity (EC), ion contents, chemistry of the effluent, as well as soil desalination. 【Result】①Water infiltrated fast during initial irrigation stage. As the waterfront moved downward, soil salt migrated with the flowing water into subsoils and infiltration rate subsequently decreased. ②After irrigation stopped, water in the topsoil continued to move downward, resulting in groundwater table rise. Drainage started when groundwater table was level with the subsurface drain. ③After drainage ended, ion content and salinity in the 0-60 cm soil profile decreased significantly, with Na? and Cl- contents decreasing by 74.47%-98.69% and 94.73%-99.28%, respectively, compared with their initial values; soil desalination in this layer was 67.5%-97.3%; the overall soil desalination in the 0-80 cm soil profile was 43.31%. ④At the end of the experiment, there was a significant shift in salt redistribution in the 0-60 cm soil layer; 1 022.69 g of salt was leached out the soil via the subsurface drains, 811.62 g remained in the 60-80 cm soil layer, and 3 968.52 g moved into the aquifer below the subsurface drain.【Conclusion】Our findings demonstrates the effectiveness of the subsurface drain in redistributing water and salt in the soil profile and salt leaching out of soil through the drain. They can help design drainage system to remediate coastal saline-alkali soil and improve agricultural production. |
| Key words: soil trough leaching; subsurface drainage; water and salt transport; desalination rate |
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