水蚀作用下土壤抗蚀能力的表征

doi:10.13826/j.cnki.cn65-1103/x.2003.01.003

摘要/Abstract

摘要： 研究区为黄土高原南部淳化县泥河沟流域, 在未经翻耕的自然或人工(耕地)坡面上, 选择56个1m²样地, (土壤为黄土, 体积含水率7.1%～20.1%, 干容重1.01g/cm³～1.29g/cm³), 采用南京土工仪器厂出产的WI-3型便携式直剪仪, 对表层0～5cm土层进行现场取样剪切, 3次重复剪切的结果表明, 表层土壤抗剪强度与土壤含水率及容重均密切相关。抗剪强度起初随含水率增加而缓缓增大, 在含水率12%～14%时达最大, 然后较迅速减弱。容重的影响表现为:随容重增大, 土壤抗剪强度呈直线趋势较快增大。通过室内降雨侵蚀实验(坡面面积为0.3m×1.0m, 雨强分别为1.39、1.49、1.88和2.66mm/min), 经对收集的溅蚀物及冲刷物称重分析发现, 无论击溅侵蚀还是径流击溅共同作用, 在土壤干容重不变(1.2 g/cm³)情况下, 试验土壤含水率达16%时, 其抗蚀能力最强。考虑到容重的影响, 把抗剪强度作为抗蚀力指标还是较为合理的。对于表层为松散状态的坡面, 将分别采自农耕地、荒地、草地、灌木地表层的原状土块(25cm×6cm×2.5cm)用水饱和后, 置于长100cm、宽6.2cm、高6.0cm的冲刷槽中, 在坡度15°, 流量5L/min条件下进行等时冲刷。用冲刷前后同一土样重量之差除以流量, 即可求出冲刷模数值。经对。

关键词: 土壤侵蚀, 抗蚀力, 指标

Abstract: Fifty-six 1 m² samples land (volume moisture of soil 7. 1%～20%, dry unit weight of 1.19～1.29 g/cm³) was selected on the sloping land in Nihegou Valley of Chunhua County in southern part of loess plateau. Using "WI-3" type Straightforward Shear Instrument made in Soil Instrument of Nanjing, 0～5 cm topsoil samples are sheared. The results of shearing showed that shear strength of topsoil was closely related to moisture and unit weight. At the initial stage, shear strength increased slowly with increasing of moisture of soil. It was maximal when the moisture was 12%～14% and then it decreased rapidly. With increasing of soil unit weight, strength of soil increased rapidly in trend of straight line. Through the experiment of sloping land of rainfall erosion in laboratory (areas of sloping land is 0.3×1.0 m 2, intensity of rainfall is 1.39, 1.49, 1.88 and 2.62 mm/min respectively), amounts of soil of splashing and scouring erosion collected showed that whether splashing erosion or scouring erosion, ant-i erosion capability is maximal when dry unit weight of soil (1.2 g/m³) was similar and moisture of soil is 16%. Therefore, considering influement of unit weight, shear strength as ant-i erosion index is reasonable. Original topsoil collected from farm land, wasteland and bush land were watered and set on scouring groove (volume 1 m×0.062 m×0.06 m). They were scoured at same time range and under the condition of 15°slope degree and 5 L/min water flow). Difference of scouring modulus soil sample weights before and after scouring divided by water flow was by contracting and analyzing clay content, dispersion coefficient, dispersion rate and organic matter. It was found that ratio of clay content of micro-aggregate and of machanical composition was closely related to scouring in unit water volume. Ant-i erosion capability of soil increased with increasing of dispersion rate. So, dispersion rate can use as indicate for ant-i erosion.

Key words: Soil erosion, an-ierosion capability, index

中图分类号:

S157.1

赵晓光, 石辉. 水蚀作用下土壤抗蚀能力的表征[J]. 干旱区地理, 2003, 26(1): 12-16.

ZHAO Xiao-guang, SHI Hui. PRESCRIPTION OF SOIL ANTI-EROSION CAPABILITY UNDER WATER EROSION[J]. Arid Land Geography, 2003, 26(1): 12-16.

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