ISWC OpenIR  > 水保所知识产出(1956---)
人为作用对土壤侵蚀环境影响的定量表征—以黄土高原典型 流域为例
庞国伟
Subtype博士
Thesis Advisor李锐
2012-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword土壤侵蚀环境 Gis 定量表征 人为作用 黄土高原
Abstract

在近代人类发展的历史过程中,人类活动对客观世界的影响日益重要和深刻。土壤
侵蚀作为一种自然过程由来已久,但由于人为活动的参与,在表现形式、侵蚀程度、空
间分布以及演变过程等均发生了根本变化。深入研究人类活动对土壤侵蚀的影响方式、
机理和过程,定量表征人类活动对土壤侵蚀的影响,对适应自然规律、合理调控人类活
动及有效开展水土流失治理具有极其重要的意义。
本研究以延河流域和纸坊沟流域为例,依据水土保持学的基本理论、运用遥感、统
计学方法,通过GIS 空间分析和数理统计,以水土保持工程措施因子(PE)和植被覆盖
与管理措施因子(C)表征地表形态和植被覆盖状况,通过分析不同时期人为作用对地
表形态、植被覆盖等的影响程度和方式,实现人为作用对土壤侵蚀环境影响的定量表征,
并基于景观生态学原理,分析了研究区植被因子景观格局的变化特征。同时以纸坊沟流
域为例,运用Hc-DEM 方法重构了不同时间序列的人工地形DEM,并在此基础上分析
了坡度、坡长等地形因子的演变特征及其影响因素,定量评价了纸坊沟流域70 多年来
土壤侵蚀演变过程及人为作用对其的影响,取得了以下主要研究结论:
(1)以水土保持工程措施因子值描述地表形态,通过构建地形人为影响指数来表
征人为作用对地形的影响程度和方式,定量分析了纸坊沟流域和延河流域人为作用对地
表形态演变的影响。纸坊沟流域、延河流域的工程措施因子值均随时间呈线性递减趋势,
地表形态的变化有利于控制土壤侵蚀。分析不同时期人类活动地形指数Ht 的变化趋势
表明:纸坊沟流域1938—1987 年人为作用对地表形态的影响程度和范围持续增加,随
后除1999—2003 年略有增加外,基本呈减小趋势,延河流域1986—2006 年人为作用对
地表形态的影响程度与范围先增加后减弱,其中1997—2000 年的人为作用对地表形态
的影响最为明显。对纸坊沟流域人工地形DEM 的分析表明,随着人类活动对地形改造
的程度不断加大,坡度、坡长、坡度因子、坡长因子、坡度坡长因子均呈减小趋势,其
中坡度变化程度最小,坡长变化程度最大,年均减小率分别为3.58%、11.94%,地形因
子值随着基本农田及居民地面积的增加而减小。
(2)以植被覆盖与管理措施因子值描述地面覆盖(植被)的状态,通过构建植被
人为影响指数来表征人为作用对地面覆盖(植被)的影响程度和作用方式,定量分析了
纸坊沟流域和延河流域人为作用对地面覆盖(植被)变化影响。纸坊沟流域的植被因子
值随时间呈4 次抛物线变化,延河流域的植被覆盖与管理措施因子值呈先增加后减小的趋势。分析植被人为影响指数Hc 的变化特征表明,纸坊沟流域1938—1958 年人类活动
对植被的影响以破坏为主,此后以恢复作用为主,人类活动对植被的恢复作用在
1987—1999 年达到最大,随后不断减小,延河流域在1986—2006 年间,人类活动对植
被破坏作用呈下降趋势,人类活动对植被的恢复作用先减小后增加。纸坊沟流域、延河
流域不同植被因子的景观格局发生了巨大变化,纸坊沟流域林地和耕地变化明显,而草
地变化不大,景观多样性指数与均匀度指数先减小后增加,而延河流域的林地、草地和
耕地均发生了较大变化,景观多样性指数与均匀度指数逐年增加。
(3)在1938—2010年70多年间,纸坊沟流域的土壤侵蚀经历了一个先增强后减弱
的过程,侵蚀模数随时间呈4次抛物线变化,1958年侵蚀模数达到最大,随后总体呈递
减趋势。1938年以中度以下侵蚀为主,1958—1978年以剧烈侵蚀为主,1978年以来,侵
蚀强度不断下降,1999—2010年微度侵蚀面积达到3.85km2,剧烈侵蚀面积仅占流域总
面积的8.96%。流域侵蚀强度受地形影响显著,随着坡度的增加,侵蚀强度与侵蚀量均
显著增加,侵蚀量主要来源于25°以上坡度带,侵蚀来源随时间有向35°以上坡度带集中
的趋势,阳坡侵蚀强度高于阴坡。在不同的土地利用类型中,林地的侵蚀强度最低,而
未利用地侵蚀强度最高,1958—1998年耕地是侵蚀产沙的主要来源,1999年以来,草地
成为流域的主要侵蚀产沙来源。经过30多年的综合治理,纸坊沟流域生态环境明显改善,
但沟谷陡荒坡侵蚀依然严重,属强烈以上侵蚀,是今后水土保持治理的重点区域。
(4)将1938 年作为人类活动加剧土壤侵蚀的基期,通过对比1958 年实际土壤侵
蚀与1938 年人类活动水平下土壤侵蚀的差异,分析了人类活动对加剧土壤侵蚀的作用;
将1958 年作为人类活动减弱土壤侵蚀的基期,通过比较1978—2010 年实际土壤侵蚀与
1958 年人类活动水平下土壤侵蚀的差异,定量分析了不同时期人类活动的减蚀作用。与
1938 年人类活动水平下的土壤侵蚀相比,1958 年在人类活动作用下增加土壤侵蚀量
24.91 万t,其中因植被覆盖变化而增加土壤侵蚀量31.09 万t,因地表形态变化而减少
土壤侵蚀量6.18 万t。与1958 年人类活动水平下的土壤侵蚀相比,1978—2010 年在人
类活动作用下减少土壤侵蚀量逐年增加,侵蚀量减少1.19~14.01 万t,其中因植被覆盖
变化而减少土壤侵蚀量0.71~11.48 万t,因地表形态变化而减少土壤侵蚀量0.48~2.53 万
t,与地表形态变化相比,植被覆盖变化对减少土壤侵蚀的作用更为明显。
关键词:土壤侵蚀环境,GIS,定量表征,人为作用,黄土高原

Other Abstract

With the progress of human history, the human being has changed the world so widely that
human being has touched every corner of the world. Soil erosion is a natural process, however,
due to human activities, great changes has taken place in erosion forms, the degree of loss, the
spatial distribution and evolution processes. Understanding how human beings influence the
soil erosion and related mechanism and processes and quantifying this influence is of great
importance to readjustment of the human activities and soil and water conservation policy
making.
This paper, took the Yanhe River watershed and Zhifanggou watershed as case study areas,
analyzed surface morphology and vegetation cover using PE-factor (soil and water
conservation engineering measures) and C-factor (vegetation and management factor) and
quantified the impact of human activities on soil erosion environment, and clarified the
variation in the vegetation pattern at the landscape scale. Meanwhile, taking a typical small
watershed of Zhifanggou watershed as an example, reconstructed artificial terrain DEM of
different time series using Hc-DEM method, and analyzed the evolution of the topographic
factors such as slope degree, and slope length and related environmental factors. After that,
a quantitative evaluation of the evolution of soil erosion in Zhifanggou in past 70 years and
the impact of human activities on this evolution was done. The main conclusions are as
follows:
(1) Delineated the surface morphology using the factor value of soil and water conservation
engineering measures, studied the extent of the impact of human activities on topography by
building an index of human activities topographic effects, and quantitatively analyzed the
human impact on the evolution of surface morphology in Zhifanggou watershed and Yanhe
River watershed The values of engineering measures factor value linearly decreased with
time in Zhifanggou watershed and Yanhe River watershed, and the changes in surface
morphology changes could help control soil erosion. The trends of topographic index Ht of  human activities in different periods showed that the extent and scope of surface morphology
resulted from human activities continued to increase in Zhifanggou watershed from 1938 to
1987, then to decrease except for a slight increasing during the period from 1999 to 2003. The
extent and scope of changes in surface morphology due to human activities increased first and
then decreased, but the most obvious impact had been observed in in period from 1997 to
2000. The analysis of man-made terrain DEM in Zhifanggou watershed showed that slope,
slope length, slope factor, slope length factor, slope of slope length factor showed a
decreasing trend as to the impact of human activities on terrain continued, which the slope
changes with minimal degree, the slope length changes with largest degree. The change in
slope length was bigger than that in slope. The average annual decreasing rate was 3.58% and
11.94% respectively, and the terrain factor valued decreased with the increase of basic
farmland and residential area.
(2) Described the surface cover(vegetation) using the value of cover-management factor,
analyzed the extent and scope of the impact of human activities on surface cover by building
human activities vegetation effects indexes, and quantitatively analyzed the human impact on
vegetation cover in Zhifanggou watershed and Yanhe River watershed. The
cover-management factor values of Zhifanggou watershed showed a 4 times parabola
relations with time, and increased first then decreased in Yanhe River watershed. The analysis
of the variation of the vegetation index Hc suggested that human activities impacted
vegetation by destruction in Zhifanggou watershed from 1938 to 1958, then by restoring
activities, and this restoring effect was most obvious from 1987 to 1999. The disruptive
impact of vegetation due to human activities decreased, and the restoring impact increased in
Yanhe River watershed from 1986 to 2006. Big changes occurred in the landscape pattern of
various vegetation factors in Zhifanggou watershed and Yanhe River watershed, the area of
woodland and farmland changed significantly in Zhifanggou watershed, and the area of
grassland changed a little, the landscape diversity and evenness index decreased first and then
increased, while the woodland, grassland and farmland changed greatly in Yanhe River
watershed, the landscape diversity index and evenness index increased year by year.
(3) During the studying period from 1938 to 2010, soil erosion experienced a dramatic
increasing period and then a decreasing one. Soil erosion modulus was the largest, and from
then on showed a generally downward trend. In 1938, soil erosion of middle degree was the
mainly erosion type, while severe erosion was the mainly erosion type during period from
1958 to 1978. Nevertheless, soil erosion declined in years from 1978 to 1998. From 1999, the
area associated with slight erosion averaged 3.85km2, while extreme erosion accounted for
8.96% of the total area of the watershed. Erosion was significantly influenced by topography  at a watershed-scale and increased dramatically with slope increase. The soil erosion mainly
occurred in slopes above 25°. Noticeably, more soil erosion was from slopes more than 35°
and south facing slopes produced more erosion than north facing ones. Among various land
use types, the slightest erosion was associated with forestland, and the strongest one with
deserted land. Farmland was the major source of erosion during 1958-1998, while in the
following period, the key area for soil conservation switched to grassland. Though the
eco-environment of Zhifanggou watershed has been markedly improved through 30 years of
comprehensive management, severe soil erosion on steep slope of gullies and hills remained a
problem demanding attention.
(4) We took 1938 as a base period with exacerbation of soil erosion by human beings, and
analyzed the role of human activity in the increase of soil erosion by comparing the
differences of soil erosion in 1958 and 1938; we then took 1958 as a base period with the
decrease of soil erosion by human activities, quantitatively analyzed the impact of human
activity on the decease of soil erosion in different periods by comparing the differences of soil
erosion between 1978-2010 and 1958, Compared to 1938, the increased soil erosion was
249111.57t in 1958 due to the human activities, of which the increase of soil erosion due to
vegetation cover changes was 310890.84t while the changes in surface morphology reduced
soil erosion by 61779.27t. Compared to 1958, the soil erosion decreased year by year due to
the human activities from 1978 to 2010.The reduced erosion was about 11870.47-140085.99t,
of which 7078.48-14442.88t was reduced by the increase of vegetation cover, and
4971.98-25301.57t was reduced due to surface morphology change. Compared to the changes
in surface morphology, vegetation cover changes reduced more soil erosion.
Key words: soil erosion environment, GIS, quantitative characterization, human activity,
Loess Plateau

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8937
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
庞国伟. 人为作用对土壤侵蚀环境影响的定量表征—以黄土高原典型 流域为例[D]. 北京. 中国科学院研究生院,2012.
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