Morphological Characteristics of Macropores and the Distribution of Preferential Flow Pathways in a Forested Slope Segment
Morphological Characteristics of Macropores and the Distribution of Preferential Flow Pathways in a Forested Slope Segment
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DOI：
10.2136/sssaj1999.6351413x
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发表时间：
1999-09
影响因子：
2.9
通讯作者：
S. Noguchi;Y. Tsuboyama;R. Sidle;I. Hosoda
中科院分区：
文献类型：
--
作者：
S. Noguchi;Y. Tsuboyama;R. Sidle;I. Hosoda
通过土壤大孔隙的水流对于确定森林流域的水文响应非常重要。使用染色剂组合评估森林山坡段的大孔形态特征和优先流动路径的分布。几乎 80% 的大孔大致呈椭圆形，偏心率范围为 0.256 至 0.998（平均值为 0.652），长度范围为 2.0 至 61.8 cm（平均值为 11.6 cm）。大孔的曲折度随着长度的增加而增加，直至30 cm左右，平均值为1.14。大孔在土壤剖面内聚集成大团块。活根和腐烂的根以及松散土壤和腐殖质的相关垂直区域促成了该土壤中的优先流动路径。通过上坡注入稀白漆溶液检测到的地下流动模式显示土壤基质和大孔之间存在强烈的相互作用。地下水流沿着基岩和 A 层和 B 层之间横向流动，两者的部分都出现了栖息地下水位。染料测试还表明，流动发生在地表基岩裂缝内。这种裂缝流有时通过局部湿润区域与大孔隙相连。因此，我们得出结论，基岩地形和裂缝特征可能对山坡尺度的优先流动路径有重大贡献。尽管单个大孔隙相当短，但这些流动路径与土壤基质、基岩裂缝、活根和腐烂根以及栖息地下水位的耦合产生了相互连接的优先流动路径的复杂网络，所有这些都有助于解释在流域中观察到的风暴流响应。通过土壤大孔隙的水流对于确定森林流域的水文响应非常重要。使用染色剂组合评估森林山坡段的大孔形态特征和优先流动路径的分布。几乎 80% 的大孔大致呈椭圆形，偏心率范围为 0.256 至 0.998（平均值为 0.652），长度范围为 2.0 至 61.8 cm（平均值为 11.6 cm）。大孔的曲折度随着长度的增加而增加，直至30 cm左右，平均值为1.14。大孔在土壤剖面内聚集成大团块。活根和腐烂的根以及松散土壤和腐殖质的相关垂直区域促成了该土壤中的优先流动路径。通过上坡注入稀白漆溶液检测到的地下流动模式显示土壤基质和大孔之间存在强烈的相互作用。地下水流沿着基岩和 A 层和 B 层之间横向流动，两者的部分都出现了栖息地下水位。染料测试还表明，流动发生在地表基岩裂缝内。这种裂缝流有时通过局部湿润区域与大孔隙相连。因此，我们得出结论，基岩地形和裂缝特征可能对山坡尺度的优先流动路径有重大贡献。尽管单个大孔隙相当短，但这些流动路径与土壤基质、基岩裂缝、活根和腐烂根以及栖息地下水位的耦合产生了相互连接的优先流动路径的复杂网络，所有这些都有助于解释在流域中观察到的风暴流响应。
Water flow through soil macropores is important in determining hydrologic responses in forested watersheds. Morphological characteristics of macropores and distribution of preferential flow pathways were evaluated in a forest hillslope segment using a combination of staining agents. Almost 80% of described macropores were roughly elliptical with eccentricities ranging from 0.256 to 0.998 (mean of 0.652) and lengths ranging from 2.0 to 61.8 cm (mean of 11.6 cm). Tortuosity of macropores tended to increase with increasing length up to about 30 cm, with a mean value of 1.14. Macropores were aggregated in large clumps within the soil profile. Living and decayed roots and associated vertical zones of loose soil and humus contributed to preferential flow pathways in this soil. Subsurface flow patterns, detected by upslope injection of dilute white paint solution, showed a strong interaction between the soil matrix and macropores. Subsurface flow was lateral along the bedrock and between A and B horizons, with a perched water table occurring on sections of both. Dye tests also showed that flow occurred within surface bedrock fractures. This fracture flow was sometimes connected to macropores through zones of local wetness. Thus, we conclude bedrock topography and fracture characteristics may contribute significantly to preferential flow pathways at the hillslope scale. Even though individual macropores were rather short, the coupling of these flow paths with the soil matrix, bedrock fractures, living and decayed roots, and perched water tables produced complex networks of interconnected preferential flow pathways, all of which help explain the stormflow response observed in the catchment. Water flow through soil macropores is important in determining hydrologic responses in forested watersheds. Morphological characteristics of macropores and distribution of preferential flow pathways were evaluated in a forest hillslope segment using a combination of staining agents. Almost 80% of described macropores were roughly elliptical with eccentricities ranging from 0.256 to 0.998 (mean of 0.652) and lengths ranging from 2.0 to 61.8 cm (mean of 11.6 cm). Tortuosity of macropores tended to increase with increasing length up to about 30 cm, with a mean value of 1.14. Macropores were aggregated in large clumps within the soil profile. Living and decayed roots and associated vertical zones of loose soil and humus contributed to preferential flow pathways in this soil. Subsurface flow patterns, detected by upslope injection of dilute white paint solution, showed a strong interaction between the soil matrix and macropores. Subsurface flow was lateral along the bedrock and between A and B horizons, with a perched water table occurring on sections of both. Dye tests also showed that flow occurred within surface bedrock fractures. This fracture flow was sometimes connected to macropores through zones of local wetness. Thus, we conclude bedrock topography and fracture characteristics may contribute significantly to preferential flow pathways at the hillslope scale. Even though individual macropores were rather short, the coupling of these flow paths with the soil matrix, bedrock fractures, living and decayed roots, and perched water tables produced complex networks of interconnected preferential flow pathways, all of which help explain the stormflow response observed in the catchment.