| Cite this article: | 庄旭东,冯绍元,于昊,等.暗管排水条件下土壤水盐运移SWAP模型模拟[J].灌溉排水学报,0,():-. |
| ZHUANG Xudong,FENG Shaoyuan,YU Hao,et al.暗管排水条件下土壤水盐运移SWAP模型模拟[J].灌溉排水学报,0,():-. |
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| Simulation of soil water-salt transport in subsurface drainage field with SWAP model |
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ZHUANG Xudong, FENG Shaoyuan, YU Hao, YUAN Chengfu, QIAN Zheng
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College of Hydraulic Science and Engineering,Yangzhou University
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| Abstract: |
| Abstract:【Background】Hetao Irrigation District in Inner Mongolia, the largest gravity irrigation district in Asia, is an important commodity grain base in China. The irrigation water from the Yellow River plays an important role in the agricultural production of Hetao Irrigation District. The agricultural irrigation water accounts for about 90% of the total water consumption in Hetao Irrigation District. It's a typical irrigation district where there is no agriculture without irrigation. Facing serious water resources shortage, our country limited the amount of water drawn from the Yellow River in Hetao Irrigation District, which aggravated the contradiction of water use in various industries. Meanwhile, the soil salinization is very serious in Hetao Irrigation District. With the application of water-saving irrigation technology and subsurface drainage technology, the original transport rule and balance conditions of soil water and salt have been broken. Therefore, it is of great significance to study soil water-salt transport in subsurface drainage field and optimize the depth and spacing of buried pipes in Hetao Irrigation District for ensuring agricultural production, improving local ecological environment and sustainable development of local national economy.【Objective】The changes of soil water flux and salinity flux in the root layer in subsurface drainage field was studied in Hetao Irrigation District in this research.【Method】The SWAP (Soil-water-atmosphere-plant) model was calibrated and validated with the field experiment data in 2018 and 2019, such as water content, salinity, leaf area index, plant height and soil texture. And the model was used to simulate soil water and salt fluxes of 40cm soil profile under different buried depth (1.5 m, 2.0 m) and spacing (30 m, 45 m). 【Result】(1) The results showed that SWAP model could better reflect the change tendency of the measured values at the process of soil water-salt calibration and validation. When there were irrigation and rainfall, the soil water flux was downward in soil profile with 40 cm in depth. For the whole growing period in 2019, the initial distance between the underground pipes was 45m and the initial buried depth was 1.5m. When the distance between the underground pipes decreased by 15 m, and the downward water flux cumulant increased by 5.2% and when the buried depth of the underground pipes increased by 0.5 m, the downward water flux cumulant increased by 83.9%. When there were no irrigation and rainfall, the soil water flux was mainly upward in soil profile with 40 cm in depth, and the change of buried depth and spacing of the underground pipe had little effect on the upward soil water flux, and the simulation results vary from 0 to 0.14 cm/d. (2) The change trend of soil salt flux was consistent with the soil water flux. For the whole growing period in 2019, the initial distance between the underground pipes was 45 m and the initial buried depth was 1.5 m. When the distance between the underground pipes decreased by 15m, and the downward salt flux cumulant increased by 5.1% and when the buried depth of the dark pipes increased by 0.5m, the downward salt flux cumulant increased by 82.6%. In addition, the change of the buried depth has obvious effect on the downward salt flux. Without the irrigation and rainfall, the soil salt flux at 40 cm profile was mainly upward, and the change of buried depth and spacing of the underground pipe also had little effect on the upward soil salt flux. 【Conclusion】The SWAP model can be used to simulate the changes of water and salt in local farmland. Increasing the depth and distance of the underground pipes were helpful to desalt the soil root layer and increase the crop yield. Considering the effect of water drainage and salt drainage and crop yield under different buried depths and spacing of underground pipes, the depth of underground pipes is 2.0m and the spacing of underground pipes is 45m. |
| Key words: SWAP model; Subsurface pipe drainage; Helianthus; Soil water-salt dynamics |
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