| 引用本文: | 张锦华,李明思,韩 寒,等.非饱和土壤中大孔隙流的影响因素研究[J].灌溉排水学报,2022,41(7):70-77. |
| ZHANG Jinhua,LI Mingsi,HAN Han,et al.非饱和土壤中大孔隙流的影响因素研究[J].灌溉排水学报,2022,41(7):70-77. |
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| 摘要: |
| 【目的】分析非饱和土壤中大孔隙流现象的影响因素及影响特点。【方法】在装有粉砂壤土的土槽中人工造出直径4 mm的通地表和不通地表的孔隙进行滴灌试验，设置3种灌水量：50、60、70 L；3种孔隙长度：50、60、70 cm；3种土壤初始含水率：5.7%、9.9%、13.3%。通过测定孔隙不同长度处的孔壁土壤含水率及相应长度处基质流区的含水率，并计算其相应的基质吸力，分析孔隙中出现大孔隙流的概率。【结果】土壤中出现大孔隙流的现象具有一定的随机性，孔隙上部（0~30 cm）出现大孔隙流的概率在2.08%~7.14%之间，下部（40~70 cm）出现大孔隙流的概率在14.58%~19.05%之间，上部出现大孔隙流的概率小于下部出现大孔隙流的概率；通地表孔隙出现大孔隙流的概率（13.04%）小于不通地表孔隙出现大孔隙流的概率（27.54%）；3种影响因素对出现大孔隙流的影响程度为：孔隙长度最大，初始含水率次之，灌水量最小。【结论】非饱和土壤中，孔隙长度对出现大孔隙流的概率影响较大；大孔隙流现象通常出现在孔隙的下半部分。 |
| 关键词: 非饱和土壤；大孔隙流；基质吸力；农田排水；土壤水分运动 |
| DOI：10.13522/j.cnki.ggps.2022023 |
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| Factors Affecting Macropore Flow in Unsaturated Soil |
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ZHANG Jinhua, LI Mingsi, HAN Han, LIU Xingshuang, XU Qiang, LAN Mingju
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College of Water Resources and Architectural Engineering, Shihezi University, Shihezi 832000, China
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| Abstract: |
| 【Objective】Preferential flow in macropores is a common hydrological phenomenon in soil. The purpose of this paper is to elucidate the factors that could affect macropore flow.【Method】The experiment was conducted in tanks repacked with a fine sandy loam soil. Macropores with diameter of 4 mm were artificially created in the soil with their top ends either exposed to the soil surface or hidden in the soil. The length of the macropores varied from 50 cm to 70 cm, and the initial soil water content varied from 5.7% to 13.3%. The tanks were drip-irrigated by 50 L, 60 L and 70 L of water, respectively. Occurrence of macropore flow was judged by appearance of liquid water on the wall of the macropores at different depths, as well as matric potential in the soil matrix. 【Result】Macropore flow did occur but varied with soil depth. The probability of its appearance was 2.08%~7.14% in the top 0~30 cm of soil, and 14.58%~19.05% in the 40~70 cm of soil. It was also found that the probability of macropore flow occurring in the macropores which stretched to the soil surface was 13.04%, less than the 27.54% in the macropores hidden in the soil. The factors that affected macropore flow more significantly was ranked in the descending order: pore depth (length) >initial water content >irrigation amount. 【Conclusion】The vertical length of the macropores affected the occurrence of macropore flow in unsaturated soil most; macropore flow is more likely to occur in the subsoil than in the topsoil. |
| Key words: unsaturated soil; macropore flow; matrix suction; farmland drainage; soil water movement |
