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1.
黄河下游防洪工程的生态环境影响分析   总被引:13,自引:1,他引:13       下载免费PDF全文
区域土壤侵蚀受到多种因素的影响和制约,在综合分析了影响福建省土壤侵蚀的主要因子:降水、地形起伏、土壤质地、植被因子和人为活动因子的基础上,根据国内外对土壤侵蚀敏感性评价的研究成果以及福建省的自然环境特征,确定了影响福建省土壤侵蚀的主要因子和敏感性等级。在GIS软件支持下,完成了评价指标数据的提取和集成,并按照敏感性等级标准进行土壤侵蚀敏感性评价。  相似文献   

2.
通过对衡山地貌和侵蚀过程分析,发现地貌是影响土壤侵蚀的基本因素,古代侵蚀地貌是现代地貌过程的基础,也决定着现代土壤侵蚀发展的规律。人类活动不能改变这种规律,却可影响土壤侵蚀的进程,土壤侵蚀加速了现代地貌过程,现代地貌过程的加速又强烈地影响土壤侵蚀程度和方式。用长时间尺度,区分古代侵蚀与现代侵蚀、正常侵蚀与加速侵蚀,将更有利于监控现代地貌过程,实施合理的水土保持措施,防止加速侵蚀,减缓现代侵蚀进程,从而保护环境和风景名胜区。  相似文献   

3.
岩溶峰丛洼地不同地貌部位土壤分布及其侵蚀特点   总被引:8,自引:1,他引:7  
以广西平果县龙何屯龙何上峰丛洼地系统为单元,通过对不同地貌部位土壤分布、土壤侵蚀和地表径流泥沙的调查监测,分析了不同地貌部位土壤剖面构型、土壤层平均厚度、土被覆盖率以及土壤分布的特点。在此基础上,着重探讨了岩溶峰丛山区不同地貌部位的土壤侵蚀强度、地表地下土壤侵蚀强度、水土流失的主要方式、地表地下土壤侵蚀的相对贡献率等特点,并对不同地貌部位土壤侵蚀的主要影响因素进行了分析。  相似文献   

4.
闽北山区土壤侵蚀演变与影响因素分析   总被引:2,自引:0,他引:2  
闽北山区地质、地貌复杂 ,降雨量多 ,经过 3次森林破坏 ,土壤侵蚀面积曾达 2 3 2 0km2 ,成为福建省土壤侵蚀的新的典型区域。区内暴雨多与降雨侵蚀力R值大、炼山全垦整地造林以及不合理的开发建设活动 ,是造成土壤侵蚀加剧的主要原因。介绍了新中国建立后区内土壤侵蚀演变的过程。  相似文献   

5.
GIS支持下的土壤侵蚀敏感性评价研究   总被引:5,自引:4,他引:5  
区域土壤侵蚀受到多种因素的影响和制约,在综合分析了影响福建省土壤侵蚀的主要因子:降水、地形起伏、土壤质地、植被因子和人为活动因子的基础上,根据国内外对土壤侵蚀敏感性评价的研究成果以及福建省的自然环境特征,确定了影响福建省土壤侵蚀的主要因子和敏感性等级。在GIS软件支持下,完成了评价指标数据的提取和集成,并按照敏感性等级标准进行土壤侵蚀敏感性评价。  相似文献   

6.
对地貌空间结构特征进行分析,可以揭示土壤侵蚀的机制、强度和空间分异,预测土壤侵蚀的发展趋势。研究表明,地形相对高差、坡度、沟壑密度与年土壤侵蚀量之间均有良好的相关关系,据此可建立地表形态各要素与年土壤侵蚀模数之间的数学模型。从地貌空间结构特征预测土壤侵蚀发展趋势具有一定的可行性。  相似文献   

7.
DEM在研究黄土丘陵沟壑区土壤侵蚀类型和过程中的应用   总被引:29,自引:1,他引:29  
DEM是通过计算机系统产生的数字高程模型,它是进行地形分析的有力工具,它能模拟地貌形态,直观显示地貌特征和地形部位,在IDRISI地理信息系统的支持下,通过数字化地形等高线图,产生数字高程模型,并通过DEM,计算派生出坡度图和坡向图,以其作为基本图件,结合土地利用图和相关资料,用地理信息系统进行综合分析,研究黄土丘陵沟壑区的土壤侵蚀类型和过程,指出了小流域土壤侵蚀类型和过程垂直分布的规律性。  相似文献   

8.
影响福建土壤侵蚀的景观因子分析   总被引:3,自引:1,他引:3  
应用福建省5类因子分布图和福建省土壤侵蚀强度图,以地理信息系统为依托,建立了全省各因子图形数据库,在此基础上,采用3种不同的数值方式计算出各因子类型的侵蚀强度系数,多样化指和集中化指数,分析了它们的因子分异,得出各因子类型的土壤蚀强度特征分异,为进行福建省土壤侵蚀景观系统分类提供依据。  相似文献   

9.
为了研究激光扫描技术应用于土壤侵蚀监测的可靠性,利用3D激光地貌分析仪对黑龙江省水土保持科技示范园内坡耕地径流小区土壤侵蚀进行监测.采用恒定降雨强度(20、40、60、80、100和120 mm/h)对径流小区进行连续6次等历时(30 min)人工降雨,每场降雨前后使用3D激光地貌分析仪对小区内不同位置的坡面形态进行扫描,并与集流桶收集土壤侵蚀量进行对比分析.结果表明:3D激光扫描分析法与集流桶测量法得到的土壤侵蚀量之间具有良好的线性相关关系,3D激光地貌分析仪用于径流小区内土壤侵蚀测定具有较高的精度与可靠性.  相似文献   

10.
孙希华 《土壤通报》2005,36(3):407-410
水土流失,其实是一种主要的侵蚀地貌演化过程。本文以戴维斯提出的地貌侵蚀循环学说为基础,把高程-面积分析法运用到流域地貌发育研究之中,把济南山丘区地貌发育阶段分为壮年期和老年期。各流域土壤侵蚀危险度平均值、土壤侵蚀强度综合指数的大小次序与其地貌发育阶段呈现良好的对应关系,说明尽管人类活动是加剧土壤侵蚀的主要原因,但地貌发育过程对土壤侵蚀的影响同样不可忽视。  相似文献   

11.
城市水土流失与环境治理   总被引:5,自引:0,他引:5       下载免费PDF全文
水土流失已被国际公认为影响环境的四大公害之一,黄土高原是我国水土流失最严重的区域。该对黄土高原山区城市水土流失的自然环境、成因和特点及对城市环境的危害进行了探讨,在此基础上提出了防治对策与建议。  相似文献   

12.
《CATENA》2004,57(1):15-34
Concentrations in the soil of anthropogenic and natural radionuclides have been investigated in order to assess the applicability of the 137Cs technique in an area of typical Mediterranean steep slopes. This technique can be used to estimate net soil redistribution rates but its potential in areas with shallow and stony soils on hard rock lithology have not been evaluated so far. In this research, the validity of using this technique in stony shallow soils at very steep slopes is discussed together with the relations between radionuclide concentrations and other soil properties, lithology, slope morphology and land use in a Mediterranean environment. Both natural Potassium-40 (40K), Uranium-238 (238U), Thorium-232 (232Th) and anthropogenic Caesium-137 (137Cs) radionuclides have been determined in samples taken along slope transects on uncultivated serpentinite soils and cultivated gneiss soils. In addition to the radionuclide concentrations, parameters such as slope position, slope angle, aspect, soil depth, surface stone cover, moss, litter, vegetation cover, soil crust, stone content and bulk density have been quantified.All the natural radionuclides 40K, 238U, 232Th show significantly higher concentrations in the gneiss than in the serpentinite soils, opposed to the 137Cs concentration, which is found significantly higher in the serpentinite soils probably because of the difference in clay mineralogy. The exponential decreasing depth distribution of 137Cs and its homogeneous spatial distribution emphasise the applicability of the 137Cs technique in this ecosystem.Lithology determines the concentration of natural and anthropogenic radionuclides. Land use determines the relations between 137Cs concentration/inventory and some soil characteristics. Higher 137Cs concentration and inventory are associated with higher percentages of vegetation cover, higher percentage of stones in the soil and higher values of soil bulk density in cultivated gneiss soils. Slope morphology and land use influence the soil redistribution at slope scale. The gneiss slopes show a zonation of four to five areas of differential erosion/accumulation processes corresponding with more regular slopes and soil redistribution due to water erosion and to tillage translocation and erosion. The serpentinites, as an example of a more unstable slope type, show more erosion areas with less accumulation downslope and soil redistribution due to water erosion.  相似文献   

13.
区域水土流失快速调查研究初报   总被引:15,自引:4,他引:11  
现代空间技术和基于GIS的土壤侵蚀定量评价预报技术,使区域土流失快速调查成为可能。建立水充失基础数据库,利用遥感技术快速调查和定期更新评价因子,开发空间型土壤流失评价模型系统,  相似文献   

14.
本文根据地质地貌特征,对正宁县的水土流失的形式、类型以及成因作了较详细的论述和分析。认为该县水土流失的形式主要有水力侵蚀和重力侵蚀,其中以水力侵蚀为主。侵蚀类型与山坡坡度、植被密度、侵蚀模数的高低以及地形的变化有关,得出本县侵蚀强度和水流输沙量自东向西有规律地递增,年侵蚀模数由东部林区的低于500吨/平方公里向西部的6,000吨/平方公里增加。由此推断了水土流失的原因是:支离破碎、千沟万壑和梁峁起伏的特殊地形;软硬相间的地层结构和集中的降水;活跃的新构造运动以及人类不合理的开发利用等。  相似文献   

15.
北京山区石灰性褐土草地雀麦播种后第2a,研究了其主要生物学特性对土壤物理性质及坡地水土流失的影响.结果表明,草地雀麦种植1a后,4月份返青,7月份地表覆盖度可达85%以上,8月份植株密度最大,地上、地下生物量为2322.6 kg/hm2和5623.0 kg/hm2,且0-10 cm地下生物量是草地雀麦地下水土保持功能发挥的主要部分.北京地区石灰性褐土土壤侵蚀的主要形式是坡面地表径流流失,降雨与植物生物学特性是坡地土壤侵蚀的主要影响因素,且不同因素作用大小表现为:地表径流量>降雨量>降雨强度>坡度>植被盖度>植被高度>植株密度.草地雀麦种植第2a,可以明显改善石灰性褐土土壤物理性质,减小土壤容重2.4%~9.8%,降低土壤紧实度,提高土壤入渗率,坡地地表年径流损失量与土壤侵蚀模数仅为13.5 mm和105.2 t/(km2·a),保水固土能力达到65.4%和98.1%,水土保持效果显著.  相似文献   

16.
Although much of the recent attention on the environmental problems has focused on climatic change, there is also increasing concern that accelerated soil erosion and associated land degradation represent a major problem for sustainable development and environmental protection. There is an urgent need to obtain reliable quantitative data on the extent and rates of soil erosion worldwide to provide a more comprehensive assessment of the magnitude of the problems and to underpin the selection of effective soil conservation measures. The use of environmental radionuclides, in particular 137Cs, affords an effective and valuable means for studying erosion and deposition within the landscape. The key advantage of this approach is that it can provide retrospective information on medium-term (30–40 years) erosion/deposition rates and spatial patterns of soil redistribution, without the need for long-term monitoring programmes. Advantages and limitations of the technique are highlighted. The launching of two closely linked International Atomic Energy Agency (IAEA) research networked projects in 1996 involving some 25 research groups worldwide has made a major contribution to co-ordinating efforts to refine and to standardise the 137Cs technique. The efficacy and value of the approach has been demonstrated by investigations in a number of environments. Significant developments that have been made to exploit its application in a wide range of studies are reported in this review paper. Other environmental radionuclides, such as unsupported 210Pb and 7Be offer considerable potential for use in soil erosion investigations, both individually and complementary to 137Cs. The IAEA through research networks and other mechanisms is promoting further development and applications of these radionuclides in soil erosion and sedimentation studies for a sustainable resource use and environmental protection.  相似文献   

17.
中国土壤侵蚀环境背景数据库的设计与建立   总被引:13,自引:5,他引:8       下载免费PDF全文
综合分析影响土壤流失和保持的环境因子将是土壤侵蚀机理,土壤侵蚀定量评价及其时空特征研究的重要手段和途径,也是土壤侵蚀的水土保持基础信息工程建设的重要内容。做为区域土壤侵蚀快速调查的一部分,本研究对中国土壤侵蚀环境数据库的设计和建立进行了初步的讨论。并提出了今后研究中的几个问题。  相似文献   

18.
Caesium-137 (137Cs) has been widely used for the determination of soil erosion and sediment transport rate. However, depth distribution patterns of 137Cs in the soil profile have not been considered. As a result, the erosion rates may be over-estimated or underestimated. This paper presents the depth distribution of 137Cs fallout in different soil profiles using published data. Three types of depth distribution functions of 137Cs are given by using statistical regression methods, the exponential type, the peak type and the decreasing type (including uniform distribution). Relationships between 137Cs loss and soil erosion rate are given by introducing the regression functions. The influence of depth distribution of 137Cs on the estimation of the soil erosion rate was simulated. Simulation results showed that very different soil erosion rates could be deduced for different depth distributions when 137Cs loss is the same, which indicates that the depth distribution pattern should be considered when soil erosion is estimated by using 137Cs. Simulation results also suggested that it is most important to determine the depth distribution of 137Cs near the soil surface and the annual relative loss of 137Cs by using the depth distribution of 137Cs as a criterion to estimate the soil erosion rate.  相似文献   

19.
为揭示季节性冻融区土壤侵蚀阻力的变化机制,确定影响土壤侵蚀阻力主控因子,通过室内冻融模拟、水槽冲刷和土壤抗剪试验,对黄绵土(SM粉质壤土)、风沙土(WS砂壤土)和黑土(KS黏壤土)侵蚀阻力影响因素进行研究。结果表明:(1)随着冻融循环次数增加,细沟可蚀性值逐渐升高,而临界剪切力降低。经历10次冻融循环后,SM粉质壤土、WS砂壤土和KS黏壤土的细沟可蚀性分别增加76%,63%,11%,临界剪切力分别减小37%,13%,91%。(2)细沟可蚀性随土壤抗剪强度、黏聚力和内摩擦角增大而减小,临界剪切力则呈相反趋势。与内摩擦角相比,黏聚力更适合用来表征土壤侵蚀阻力。采用黏聚力对SM粉质壤土、WS砂壤土和KS黏壤土的细沟可蚀性进行预测,决定系数(R2)分别为0.42,0.78,0.50,平均为0.57;对临界剪切力的预测效果较差,决定系数(R2)分别为0.16,0.14,0.18,平均仅为0.16。(3)根据皮尔逊相关分析结果,基于土壤的初始含水率、冻融循环次数、力学特性以及土壤参数等分别建立细沟可蚀性(R2=0.85)和临界剪切力...  相似文献   

20.
《CATENA》1998,32(1):23-35
Several studies have documented the severity of recent soil erosion on the Canadian prairies where cultivation started about a century ago. Little quantitative information is available on erosion before 1960. This study attempts to quantify post- and pre-1960 soil erosion in a small cultivated basin near Saskatoon, Saskatchewan, Canada, by measuring 137Cs and magnetic susceptibility (χ) distribution with depth. Soil cores were collected along six transects (three across closed depressions and three across the drainage channel) in the cultivated field, and one transect across an uncultivated depression. The cores were sliced into 3-cm layers and the soil analyzed for 137Cs, χ, and organic and inorganic C. High variability in χ with depth in eroding areas (as indicated by 137Cs) made it impossible to use χ to quantify past soil losses in these locations. However, these eroding upper and middle slope positions have a much higher χ than lower slope areas where soil deposition occurs and where the variability in χ with depth could be used to estimate soil deposition. Estimating soil deposition from the χ vs. depth profiles was more successful in the closed depressions than in the drainage channel, where the χ profiles may reflect the variable source areas of the materials rather than the pedological conditions. The data indicated that soil deposition since 1960 has been about 30 to 50% of that prior to 1960. This suggests that soil deposition rates, and by implication, soil erosion rates, have been relatively steady since cultivation of these soils started, although there are clear indications that the spatial pattern of deposition has varied.  相似文献   

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