| 引用本文: | 张 丽,焦平金,董勤各,等.暗管间距和埋深对田间水盐运移变化的影响[J].灌溉排水学报,2023,42(9):92-101. |
| ZHANG Li,JIAO Pingjin,DONG Qin’ge,et al.暗管间距和埋深对田间水盐运移变化的影响[J].灌溉排水学报,2023,42(9):92-101. |
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| 摘要: |
| 【目的】研究河套灌区漫灌模式下田间尺度不同暗管间距和埋深对土壤水盐运移特征的影响。【方法】基于田间监测数据率定验证HYDRUS-2D模型，并模拟暗管埋深1.5 m下5种间距（5、15、25、50、100 m）与暗管间距25 m下5种埋深（0.6、1.0、1.5、2.0、2.5 m）下的排水排盐量和土壤剖面水盐时空分布特征。【结果】①模型模拟水盐变化的精度较高，土壤剖面水分和盐分模拟结果的决定系数R2分别为0.81和0.71，均方根误差RMSE分别为0.038和0.026，纳什系数NSE分别为0.93和0.86。②累积排水量和排盐量随暗管间距减小和暗管埋深增加而增加，埋深1.5 m下暗管间距从100 m减至5 m排水总量增长了4.96倍，排盐总量增长了5.06倍；暗管间距25 m下埋深从0.6 m增至2.5 m排水总量增长了64.24倍，排盐总量增长了60.08倍。③土壤剖面含水率在排水期随暗管间距减小和埋深增加而降低，土壤剖面含水率降幅随时间增加而减小；土壤剖面含盐量在非排水期随暗管间距减小和埋深增加而降低，土壤剖面含盐量降幅随时间增加而增大。④水平方向，土壤含盐量在非排水期随水平距离的增加而增大，增幅随暗管间距减小和埋深增大而减小。埋深1.5 m下暗管间距5 m与暗管间距100 m土壤含盐量差异从暗管处的26.67%增加到暗管中间的39.88%，暗管间距25 m下埋深0.6 m与埋深2.5 m土壤含盐量差异从暗管处的30.56%增加到暗管中间的50.39%；垂直方向，土壤含水率随土层深度增加呈先增大后减小的“镰刀”状变化；排水初期土壤含盐量随土层深度的增加而增大，非排水期随土层深度的增加而减小。【结论】减少暗管间距和增加暗管埋深可有效提高暗管排水排盐量并降低排水期的土壤剖面蓄水量和非排水期的土壤剖面积盐量，初步认为暗管间距在15~50 m，暗管埋深在1.0~2.0 m范围内作为河套灌区的暗管排水布设参数较为合适。 |
| 关键词: 暗管排水；水盐运移；暗管间距；暗管埋深；HYDRUS-2D |
| DOI：10.13522/j.cnki.ggps.2022681 |
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| 基金项目: |
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| Effects of Spacing and Depth of Subsurface Drain on Water and Salt Transport in the Field |
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ZHANG Li, JIAO Pingjin, DONG Qin’ge , TAO Yuan
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1. College of Water Resource and Architectural Engineering, Northwest A & F University, Yangling 712100, China;
2. Institute of Water Conservancy, China Institute of Water Resources and Hydropower Research, Beijing 100048, China;
3. Key Laboratory of Agricultural Soil and Water Engineering in Arid Areas, Ministry of Education, Northwest A & F University,
Yangling 712100, China; 4. Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, China
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| Abstract: |
| 【Objective】Subsurface drains are commonly used in drainage system. This paper investigates the effect of their spacing and depth on water movement and salt transport in field soil under flood irrigation in Hetao Irrigation District.【Methods】The study was based on data measured from a field, which were used to calibrate the HYDRAS-2D model. The validated model was then used to predict spatiotemporal changes in water flow and salt transport when the drain depth was 1.5m by varying the drain spacing from 5 to 100 m, and when the drain spacing was 25 m by varying the drain depth from 0.6 to 2.5 m.【Result】①The model is accurate for simulating both water flow and salt transport, with the coefficient of determination R2 for soil profile moisture and salinity being 0.81 and 0.71, the RMSE error being 0.038 and 0.026, and the Nash coefficient NSE being 0.93 and 0.86, respectively. ②The cumulative displacement and salt discharge increased with the decrease in drain spacing and the increase in drain depth. When the drain depth was 1.5 m, decreasing drain spacing from 100m to 5m increased total drainage by 4.96 times and increased the salt discharge by 5.06 times. When drain spacing was 25 m, increasing drain depth from 0.6 m to 2.5 m increased the total drainage by 64.24 times, and the total salt discharge by 60.08 times. ③The water content in the soil profile decreased with the decrease in drain spacing and drain depth during the drainage period, and the decrease decreased as time elapsed. The salt content in the soil profile decreased with the decrease in drain spacing and depth in non-drainage period, and the decrease increased as time elapsed. ④Horizontally, salt content in the soil increased with the increase in the distance from the drain in non-drainage period, and the increase decreased with an decrease in drain spacing and an increase in drain depth. When drain depth was 1.5 m, the difference in soil salinity between the drain spacing 5 m and 100 m increased from 26.67% in the region proximal to the drains to 39.88% in the middle of the drains. When the drain spacing was 25 m, the difference in soil salinity between the drain depth 0.6 m and 2.5 m increased from 30.56% in the region adjacent to the drain to 50.39% in the middle of the drains. Vertically, soil water content varied in a “sickle” shape with the increase in soil depth. The initial drainage of salt increased with the increase in drain depth, while in non-drainage period it decreased with the increase in drain depth.【Conclusion】Reducing drain spacing or increasing drain depth can improve the drainage and salt discharge, thereby reducing water storage in soil profile during drainage period and soil salt content during non-drainage period. Our results suggested that the optimal drain spacing was 15~50 m and the drain depth was 1.0~2.0 m for Hetao irrigation district. |
| Key words: subsurface pipe drainage; water and salt transport; subsurface pipe spacing; subsurface pipe buried deep; HYDRUS-2D |
