ISWC OpenIR  > 水保所知识产出(1956---)
东北黑土区土壤侵蚀过程机理和土壤养分迁移研究
安 娟
Subtype博士
Thesis Advisor郑粉莉
2012-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword雨型 壤中流 侵蚀机理 养分迁移 东北黑土区。
Abstract

东北黑土区是我国重要的粮食产区,严重的土壤侵蚀和养分流失直接威胁我国的粮
食战略安全。因此,深入理解黑土区土壤侵蚀机理是保护黑土资源的迫切需求。本文针
对我国黑土区土壤侵蚀机理与养分流失研究相对薄弱的现状,基于模拟降雨试验、室内
分析、137Cs示踪法和GIS技术相结合的研究方法,研究了雨滴打击、壤中流+地表径流共
同作用这两种侵蚀动力下的坡面土壤侵蚀过程,评价了降雨特征(雨强和雨型)、坡度
和地表覆盖对坡面土壤侵蚀过程的影响,揭示了坡面土壤侵蚀的动力学机理,并探究了
不同侵蚀条件下氮和磷的迁移机制,阐明了流域土壤侵蚀空间分布特征。主要研究结论
如下:
( 1 ) 研究了雨滴打击对坡面土壤侵蚀的作用。雨滴侵蚀占总侵蚀量的
72.29%~96.21%。消除雨滴打击作用后径流深、流速、雷诺数和弗汝德数分别减少了
3.85%~39.34%、20.9%~67.5%、25.82%~70.29%和18.75%~62.50%,而阻力系数增加了
39.90%~430.91%。相关分析和通径分析的结果表明,流速是影响雨滴侵蚀的关键水力学
参数。与无雨滴打击处理下相比,雨滴打击可使临界径流剪切力、水流功率和单位水流
功率增加2倍以上。
(2)分析了壤中流与地表径流共同作用下的坡面土壤侵蚀过程和机理。与无壤中
流条件下相比,壤中流与地表径流共同作用下侵蚀量增加50.84%~74.34%,相应的坡面
水流流速、雷诺数和弗汝德数分别增加2.74%~50.11%、4.03%~77.22%和2.08%~37.51%,
而阻力系数减少4.52%~60.44%,侵蚀水动力参数径流剪切力、水流功率和单位水流功率
分别增加1.42%~24.64%、4.04%~77.22%和2.74%~50.49%。
(3)阐明了不同雨型下的坡面侵蚀过程和机理。变雨强雨型下的侵蚀量显著高于
均匀雨型下的侵蚀量,其中增加型雨型下的侵蚀量最大。增加型、减弱型和减弱-增加
型雨型下的侵蚀量分别是均匀型雨型下的1.83~5.17、1.62~3.79 和1.13~3.79 倍。同一
雨强不同发生时序对坡面土壤侵蚀有显著影响。与均匀型雨型下相比,变雨强雨型下
的流速、雷诺数和弗汝德数均显著增加,其中增加型雨型下水力学参数的增加幅度最
大。变雨强雨型下的径流剪切力、水流功率和单位水流功率较均匀型雨型下分别增加了10.28%~101.46%、8.89%~173.33%和6.75%~88.40%。
(4)建立了试验条件下的坡面土壤侵蚀量的估算方程。通过相关分析、通径分析和
因子分析发现雨滴打击与径流共同作用下,单位水流功率(ψ)和弗汝德数(Fr)是影
响坡面侵蚀量(Dr)的主控因子,其拟合方程为Dr=4.787 Fr3.547ψ-0.008;径流侵蚀下,影
响坡面侵蚀量的主控因子则为单位水流功率和雷诺数(Re),其拟合方程为Dr=0.002
Re0.76ψ0.53,且方程具有较高的预报精度。
(5)揭示了不同近地表水文条件下的土壤养分迁移机制。壤中流条件下,径流中
NO3-N、NH4-N 和 PO4-P 的浓度分别是自由入渗条件下的228.7~294.0,38.4~42.9 和
7.3~10.2 倍。径流和泥沙中养分流失量均表现为:壤中流+降雨>土壤水分饱和>自由入
渗。土壤水分饱和与壤中流+降雨条件下径流中NO3-N 的浓度分别是自由入渗条件下
的4.06~5.75 和14.8~20.96 倍,NH4-N 分别为1.26~1.36 和1.74~2.09 倍,PO4-P 分别
为1.29~1.90 和1.57~2.20 倍。计算了不同近地表水文条件下NO3-N 的等效径流迁移深
度,发现自由入渗条件下,NO3-N 的等效径流迁移深度小于3 mm;土壤水分饱和与
壤中流+降雨条件下,NO3-N 的等效径流迁移深度均大于10 mm。
(6)基于137Cs 示踪法和GIS 技术分析了黑土区小流域的土壤侵蚀空间分布特
征。流域上游以侵蚀为主,中游侵蚀与沉积交替出现,下游主要发生沉积。在坡长方
向上表现为坡上部侵蚀强度较弱,坡中部侵蚀较为严重,而坡脚发生沉积。流域土壤
侵蚀以坡面侵蚀为主,其侵蚀量占流域总侵蚀量的95.7%。全流域平均侵蚀模数为
571.5 t km-2 a-1。
关键词:雨型;壤中流;侵蚀机理;养分迁移;东北黑土区。

Other Abstract

Black soil region is a major food production area in China, while serious soil erosion and
nutrient loss directly threaten grain security strategy of our country. Therefore, deep
understanding mechanisms of soil erosion are an urgent demand to protect black soil
resources. In view of the insufficiency research of soil erosion processes and nutrient loss in
the black soil region of Northeast China, this study took the black soil as the research object
to study processes and mechanisms of soil erosion, and nutrient migration mechanisms based
on rainfall simulation experiments, the137Cs tracer technology, GIS technology and laboratory
analysis. Mechanisms of soil erosion were studied under two kinds of erosion dynamics that
were raindrop impact, and the combining action of seepage flow and surface flow. Then the
study evaluated the effects of rainfall characteristic (rainfall intensity and storm patterns),
slope gradient, and soil surface cover on soil erosion processes, and illustrated hydro-dynamic
mechanism of soil erosion from the perspective of flow hydraulics and hydrodynamic
mechanism of sediment yielding. Migration mechanisms of nitrogen and phosphorus were
explored under different soil erosion conditions. Finally, this study clarified spatial
distribution of soil erosion at the watershed scale. Main conclusions of this study were as
follows:
(1) The role of raindrop impact on hillslope soil erosion processes was investigated.
Sediment yield induced by raindrop impact occupied 72.29%-96.20% of the total sediment
yield. When raindrop impact was eliminated, runoff depth, flow velocity, Reynolds number,
and Froude number decreased 3.85%-39.34%, 20.9%-67.5%, 25.82%-70.29%,
and18.75%-62.50%, respectively; whereas Darcy-Weisbach coefficient increased
39.90%-430.91%. Flow velocity was the key hydraulic parameters of affecting raindrop
erosion according to the correlation analysis and path analysis. Further, raindrop impact
resulted in the critical shear stress, the critical stream power, and the critical unit stream  power increased above 2 times, compared with the condition without raindrop impact.
(2) Effects of the interaction of seepage flow and surface flow on hillslope soil
erosion processes were analyzed. Compared with the treatment without seepage flow,
sediment yield from the treatment with seepage flow and surface flow increased
50.84%-74.34%, these corresponding hydraulic parameters of flow velocity, Reynolds
number, and Froude number increased 2.74%-50.11%, 4.03%-77.22%, and 2.08%-37.51%,
respectively, while Darcy-Weisbach coefficient decreased 4.52%-60.44%, and shear stress,
stream power, and unit stream power increased 1.42%-24.64%, 4.04%-77.22%,
respectively.
(3) Processes and hydro-dynamic mechanism of soil erosion under different storm
patterns were revealed. Sediment yield from the storms of varying rainfall intensity was
significantly greater than that from the storms of stable rainfall intensity. Among, the rising
storm pattern gave a consistently higher sediment yield relative to other storm patterns.
Sediment yield from the rising, falling, and falling-rising storm patterns was 1.83-5.17,
1.62-3.79, and 1.13-3.79 times, respectively, greater than that from the even storm pattern.
Also, significant difference in sediment yield was observed between different steps of
rainfall intensity occurrence in different storm patterns. Compared with even-intensity
storms, flow velocity, Reynolds number, and Froude number from varying-intensity storms
increased significantly and hydraulic parameters from the rising storm pattern showed the
largest increasing amplitude. Shear stress, stream power, and unit stream power from
varying-intensity storms increased by 10.28%-101.46%, 8.89%-173.33%, and
6.75%-88.40%, compared with those from even-intensity storm.
(4) The estimation equations of soil erosion were established under experimental
conditions. Based on the sensitivity analysis, path analysis, and factor analysis, it was found
that unit stream power (ψ) and Froude number (Fr) were the main-control factors of soil
erosion for the treatment with raindrop impact, and the relationship between sediment yield
per unit width (Dr) and these main-control factors was expressed by: Dr=4.787 Fr3.547ψ-0.008;
unit stream power and Reynolds number (Re) became the key factors of soil erosion for the
treatment only with runoff erosion, and the relationship between Dr and these key factors took
the following form: Dr =0.002 Re0.76ψ0.53. Verified by the information of actual measurement,
the two equations showed higher precision.
(5) Nutrient migration mechanisms under different soil surface water regimes were
revealed. NO3-N, NH4-N, and PO4-P concentrations from the seepage treatment were
228.7-294.0, 38.4-42.9, and 7.3-10.2 times greater than those from the free drainage treatment,  respectively. Both nutrient losses in runoff and sediment yield ranked in order: the seepage
with rainfall treatment>the saturation treatment>the free drainage treatment. NO3-N, NH4-N
and PO4-P concentrations in runoff from the saturation and seepage with rainfall treatments
were significantly greater than those from the free drainage treatment, with magnitudes of
4.06-5.75 and 14.8-20.96 times greater for NO3-N, 1.26-1.36 and 1.74-2.09 times greater for
NH4-N, and 1.29-1.90 and 1.57-2.20 times greater for PO4-P, respectively. Further, it was
found that the effective erosion transport depth by runoff of NO3-N was less than 3 mm for
the free drainage treatment, while it was more than 10 mm for the saturation and seepage with
rainfall treatments.
(6) The spatial distribution of soil erosion and deposition in a small catchment of black
soil region was revealed using 137Cs tracer technique and GIS technology. Soil erosion
played a dominated role in the upstream of the catchment, and erosion and deposition
appeared alternately in the middle reach of the catchment, while deposition took a leading
position in the downstream of the catchment. Along the slope length, soil erosion was
slightly at the top of slope, and erosion became more serious at the middle of slope, while
deposition occurred at the toe of slope. Slope erosion occupied 95.7% of the catchment
erosion. The mean erosion modulus was 571.5 t km-2 a-1for this catchment.
Key Words: storm pattern; seepage; mechanisms of soil erosion; nutrient transportation; the
black soil region of Northeast China.

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8931
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
安 娟. 东北黑土区土壤侵蚀过程机理和土壤养分迁移研究[D]. 北京. 中国科学院研究生院,2012.
Files in This Item:
File Name/Size DocType Version Access License
东北黑土区土壤侵蚀过程机理和土壤养分迁移(3105KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[安 娟]'s Articles
Baidu academic
Similar articles in Baidu academic
[安 娟]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[安 娟]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.