共查询到20条相似文献，搜索用时 125 毫秒
1.
Relationships between the soil organic carbon density of surface soils and the influencing factors in differing land uses in Inner Mongolia 总被引：1，自引：0，他引：1
Binyong Li Haiping Tang Liheng Wu Qinghuan Li Chunrong Zhou 《Environmental Earth Sciences》2012,65(1):195-202
Land use patterns are changing and the environment has become more vulnerable in an agro-pastoral ecotone in Inner Mongolia.
Modeling studies can be done through studying the relationships between the soil organic carbon density (SOCD) and the influencing
factors in differing land uses such as cropland, forest and grassland. Such studies can provide the basis for predicting soil
organic carbon (SOC) stocks and using land resources efficiently. Therefore, the relationships between the SOCD of surface
soils and the influencing factors, such as soil type, slope and elevation, were selected for a study in differing land uses
of Duolun County, Inner Mongolia. The results showed that: (1) The variation in SOCD among the soil types followed the same
order in the three land uses: chernozems > meadow soils > bog soils > castanozems > gray-cinnamon soils > eolian soils. The
sensitivity of SOCD to land use change was different for the six soil types. Both the degradation of grassland and the application
of the government policy of returning forest from cropland induced the greatest variation in SOCD. (2) SOCD correlated significantly
with soil type and elevation in each land use. There was a significant correlation between SOCD and slope in the forest. (3)
Statistical models showing SOCD and the influencing factors were developed and provided the basis for predicting SOC stocks
in Duolun County, Inner Mongolia. 相似文献
2.
Xi Wang Zhang Bing Fang Wu Xiao Song Li Shan Long Lu 《Environmental Earth Sciences》2012,65(1):221-229
The spatial pattern of soil erosion can provide valuable insights into the soil erosion processes that require a rapid assessment
in practical applications. Generally, quantitative technique is expensive and time-consuming. The objective of this paper
is to reveal the spatial pattern of erosion with a rapid assessment method. The affecting factors such as land cover, vegetation
fraction and slope gradient are integrated into this method using a qualitative means. Beijing-1 images in 2006 were used
to produce land-cover and vegetation fraction, and 1:50,000 topographic maps were used to calculate slope gradient. The study
area was classified into six grades. Results show that the upstream area of Guanting Reservoir, in general, is exposed to
a moderate risk; there are 17,740.33 km2 of land that suffered from water soil erosion in 2006, occupied 40.69% of the total area, and most of the soil erosion area
is on the light and moderate risk, which occupied 25.05 and 62.83% of the eroded area, respectively. Eight elevation zones
and six slope gradient zones were overlaid with the assessed risk. The analyzed results show that: (1) the areas above 2,000 m
have the lowest erosion risk, which is only 0.75% of the eroded area; 1,250–1,500 m elevation zone has the highest erosion
risk, which is 34.72% of the eroded area. (2) The slope gradient zone less than 5 degrees and greater than 35 degrees have
the lowest erosion risk, which is 0.02 and 0.75% of the eroded area, respectively; the slope gradient zone with 8–15 degrees
has the highest erosion risk, which is 36.40% of the eroded area. These results will be useful for water and soil conservation
management and the planning of mitigation measures. 相似文献
3.
The main objective of this study is to assess the land degradation risk of cultivated land in El Fayoum depression. The physiographic map of the depression was produced by using remote sensing and land surveying data. The depression comprises lacustrine plain, alluvial–lacustrine plain, and alluvial plain representing 12.22%, 53.58%, and 34.20% of the total area, respectively. The soil, climate, and topographic characteristics of the depression were extracted from land surveying, laboratory analyses, digital elevation model, and available reports. A simple model was designed to employ these data for assessing the chemical and physical risk of land degradation using Arc-GIS 9.2 software. The obtained results indicate that severe risk to chemical and physical degradation affect 54.15% and 29.23% of the depression, respectively. The current status of soil salinity, sodicity, and water table indicate that most of lacustrine and alluvial–lacustrine soils are actually degraded by salinization, sodification, and waterlogging. The results of degradation risk and the actual hazard indicate that the human activities are not sufficient to overcome the degradation processes in the most of the depression (80. 22%). Moreover, a negative human impact affects 26.29% of the area mostly in the alluvial plain. Great efforts related to the land management are required to achieve the agriculture sustainability. 相似文献
4.
This research selected water soil erosion indicators (land cover, vegetation cover, slope) to assess the risk of soil erosion,
ARCMAP GIS ver.9.0 environments and ERDAS ver.9.0 were used to manage and process satellite images and thematic tabular data.
Landsat TM images in 2003 were used to produce land/cover maps of the study area based on visual interpreting method and derived
vegetation cover maps, and the relief map at the scale of 1:50,000 to calculate the slope gradient maps. The area of water
soil erosion was classified into six grades by an integration of slope gradients, land cover types, and vegetation cover fraction.
All the data were integrated into a cross-tabular format to carry out the grid-based analysis of soil erosion risk. Results
showed that the upper basin of Miyun Reservoir, in general, is exposed to a moderate risk of soil erosion, there is 715,848 ha
of land suffered from water soil erosion in 2003, occupied 46.62% of total area, and most of the soil erosion area is on the
slight and moderate risk, occupied 45.60 and 47.58% of soil erosion area, respectively. 相似文献
5.
Not only the nutritional status and biological activity but also the soil ecological functioning or soil health has been impacted profoundly by land degradation in the karst area of southwest China where the karst ecosystems are generally considered as extremely vulnerable to land degradation under intensified land-use changes. The objectives of this study are to elucidate the changes in overall soil quality by a holistic approach of soil nutritional, biological activity, and soil health indicators in the karst area as impacted by intense cultivation and vegetation degradation. Topsoil samples were collected on selected eco-tesserae in a sequence of land degradation in a karst area of southwest Guizhou in 2004. The soil nutrient pools of organic carbon (Corg), extractable extracellular carbon (Cext), total soil nitrogen (Nt), alkali-hydrolyzable nitrogen (Nah), total phosphorus (Pt), available phosphorus (Pa) were analyzed by wet soil chemistry. The soil biological properties were studied by means of measurements of microbial biomass carbon (both by fumigation–extraction, FE-Cmic, and by calculation from substrate-incubation respiration, SIR-Cmic) of respiration [respiration without addition of substrates, basal respiration (BR), and potential respiration (PR) with substrate-incubation] and of soil enzyme activities (invertase, urease, and alkaline phosphatase). Soil health status was assessed by simple indices of Cmic/Corg and BR/Cmic in conjunction with bacterial community structures determined by polymerase chain reaction and denaturing gradient gel electrophoresis. While the nutritional pool parameters, such as Corg and Cext, described basically the changes in soil life-supporting capacity with cultivation interference and vegetation declined, those parameters of biological activity such as FE-Cmic, SIR, and SIR-Cmic as well as bacterial community structures measured by molecular method evidenced well the changes in soil functioning for ecosystem health with the land degradation. 相似文献
6.
Spatio-temporal evolution of rocky desertification and its driving forces in karst areas of Northwestern Guangxi, China 总被引：6，自引：1，他引：5
Qing-qing Yang Ke-lin Wang Chunhua Zhang Yue-min Yue Ri-chang Tian Fei-de Fan 《Environmental Earth Sciences》2011,64(2):383-393
Rocky desertification (RD) is a process of land degradation that often results in extensive soil erosion, bedrock exposure and considerable decrease of land productivity. The spatio-temporal evolution of RD not only reflects regional ecological environmental changes but also directly impacts regional economic and social development. The study area, Hechi, is a typical karst peak cluster depression area in southwest China. Remote sensing, geographic information systems (GIS) and statistical techniques were employed to examine the evolution, including the identification of driving forces, of karst RD in the Northwestern Guangxi. The results indicate that RD became most apparent between 1990 and 2005 when areas of various types of RD increased. Within the karst RD landscape, slight RD was identified as the matrix of the landscape while potential RD had the largest patch sizes. Extremely strong RD, with the simplest shape, was the most influenced by human activities. Overall the landscape evolved from fragmented to agglomerate within the 15-year timeframe. Land condition changes were categorized as five types; desertified, recovered, unchanged, worsened, and alleviated land. The largest turnover within the RD landscape was between slight and moderate RD. With regards to the driving forces all RD had been increasingly influenced by human activities (i.e., the stronger the RD, the stronger the intensity of human disturbances). Dominant impact factors of the RD landscape had shifted from town influence and bare rock land in 1990 to bare rock and grassland in 2005. Moreover, the impacts of stony soil, mountainous proportion and river density on RD increased over time, while that of others decreased. The significant factors included human activities, land use, soil types, environmental geology, and topography. However, only anthropogenic factors (human activities and land use) were reported as leading factors whereas the others acted simply as constraining factors. 相似文献
7.
Spatio-temporal patterns of agricultural expansion and its effect on watershed degradation: a case from the mountains of Nepal 总被引：1，自引：1，他引：0
K. C. Krishna Bahadur 《Environmental Earth Sciences》2012,65(7):2063-2077
Expansion of agricultural at the cost of forested land is a common cause of watershed degradation in the mountain zones of
developing countries. Many studies have been conducted to demonstrate land use changes in such regions. However, current knowledge
regarding the changes, driving forces and implications of such change within the context of watershed development is limited.
This study analyses changes in spatial patterns of agricultural land use and their consequences for watershed degradation
during the 1976–2000 period along an altitude gradient in a watershed in Nepal, by means of remote sensing, GIS and the universal
soil loss equation. Estimated soil loss ranged from 589 to 620 t ha−1 y−1, while areas of extreme hazard severity (>100 t ha−1) increased from 9 to 14.5% from 1990 to 2000. Spatial distribution of soil loss in 2000 was characterized by 88% of total
soil losses being from upland agricultural areas. The study determined that without considering other forms of land degradation,
only water erosion was responsible for erosion of a substantial area in a short timeframe. Areas under upland cultivation
are in an extremely vulnerable state, with these areas potentially no longer cultivable within a period of 6 years. As sustainability
of the watershed is dependent on forests, continued depletion of forest resources will result in poor economic returns from
agriculture for local people, together with loss of ecosystem services. Thus, in order to achieve the goal of watershed development,
remaining forest lands must be kept under strict protection. 相似文献
8.
基于遥感影像的决策树分类,结合土地利用图,将北京市农业地表覆盖划分为春玉米、冬小麦、果园、林木苗圃、牧草地、设施农业和畜禽饲养地。考虑海拔、坡度和土壤质地三个因子将北京市分成10个景观区,在景观分区和不同农业用地基础上划分出39类农业景观单元。利用基于遥感影像计算的归一化差异植被指数,结合实地调查验证,分类出北京市冬春季裸露农田。结合景观分类,分析了不同景观单元冬春季地表裸露情况。结果表明：2007—2008年冬春季裸露农田共8.05×104 hm2,主要分布在延庆盆地、密云水库北岸和城区边缘的近郊农业区;海拔和土地利用方式对裸露情况影响较大,其中山区春玉米和平原果园裸露情况绝对面积较大,分别占到总裸露农田面积的40%和17%,牧草地、林木苗圃与设施农业地裸露程度较高。基于不同景观单元裸露程度,结合绿肥种植、保护性耕作、生草覆盖等裸露农田治理方法,探讨了北京市农业产业和景观一体化建设策略。 相似文献
9.
云南小江流域不同土地利用类型土壤微量元素的对比分析 总被引：1，自引：0，他引：1
文章对云南小江流域不同土地利用类型（耕地、林地、园地、建设用地、裸地）土壤的微量元素进行空间插值、方差分析和相关性研究,旨在探讨云南小江流域不同土地利用类型微量元素的分布和迁移规律。结果表明:除Mo的含量较低外,小江流域土壤中Cu、Mn、Ni和Zn的含量普遍较高。各微量元素含量在不同土地利用类型中具有明显的差异性,园地土壤微量元素含量最高。微量元素的变异程度均属于中等变异。Cu、Mn、Mo、Ni、Zn的空间分布具有一定的相似性,高值区主要集中在海拔较低的岩溶河谷区右侧和盆底沉积平坝区,主要土壤类型为碳酸盐岩红壤;低值区集中在海拔较高的河谷区左侧和中山区,主要土壤类型为碎屑岩。地貌、土壤母岩和人为活动是影响微量元素分布和迁移的重要因素。 相似文献
10.
荒漠化是指人类历史时期以来,由于人类不合理的经济活动和脆弱生态环境相互作用造成土地生产力下降,土地资源丧失,地表呈现类似荒漠景观的土地退化过程。在中国北方荒漠化形成因素中过度放牧占30．1％,过度农垦占26．9％,过度樵采占32．7％,水资源利用不当占96％,工矿交通建设中不注意环境保护占0．7％,在地区上以北方农牧交错及旱农地区荒漠化最为严重。要采取因地制宜措施和建立健全而完善的治理实施系统以达到生态、经济和社会三个效益的目的。 相似文献
11.
Shallow-landslide susceptibility in the Costa Viola mountain ridge (southern Calabria,Italy) with considerations on the role of causal factors 总被引：2，自引：1，他引：1
Giulio G. R. Iovine Roberto Greco Stefano L. Gariano Annamaria D. Pellegrino Oreste G. Terranova 《Natural Hazards》2014,73(1):111-136
The “Costa Viola” mountain ridge (southern Calabria), in the sector between Bagnara Calabra and Scilla, is particularly exposed to geo-hydrological risk conditions. The study area has repeatedly been affected by slope instability events in the last decades, mainly related to debris slides, rock falls and debris flows. These types of slope movements are among the most destructive and dangerous for people and infrastructures, and are characterized by abrupt onset and extremely rapid movements. Susceptibility evaluations to shallow landslides have been performed by only focusing on source activation. A logistic regression approach has been applied to estimating the presence/absence of sources in terms of probability, on the basis of linear statistical relationships with a set of territorial variables. An inventory map of 181 sources, obtained from interpretation of air photographs taken in 1954–1955, has been used as training set, and another map of 81 sources, extracted from 1990 to 1991 photographs, has been adopted for validation purposes. An initial set of 12 territorial variables (i.e. lithology, land use, soil sand percentage, elevation, slope angle, aspect, across-slope and down-slope curvatures, topographic wetness index, distance to road, distance to fault and index of daily rainfall) has been considered. The adopted regression procedure consists of the following steps: (1) parameterization of the independent variables, (2) sampling, (3) calibration, (4) application and (5) evaluation of the forecasting capability. The “best set” of variables could be identified by iteratively excluding one variable at a time, and comparing the ROC results. Through a sensitivity analysis, the role of the considered factors in predisposing shallow slope failures in the study area has been evaluated. The results obtained for the Costa Viola mountain ridge can be considered acceptable, as 98.1 % of the cells are correctly classified. According to the susceptibility map, the village of Scilla and its surroundings fall in the highest susceptibility class. 相似文献
12.
石漠化景观生态优化途径初探——以贵州清镇王家寨小流域为例 总被引：1，自引：1，他引：0
以治理石漠化、维护喀斯特景观生态安全和土地资源的可持续利用为目标,以景观生态学理论为指导,选择西南典型喀斯特石漠化地区— — 贵州清镇王家寨流域为研究区,并建立了源于最小累计阻力模型的生态恢复耗费表面模型,其步骤如下: 首先以2005年SPOT影像为基础,依托遥感和地理信息系统软件,对研究区土地类型进行分类,同时从数字高程模型中提取两种地形因子(坡度和坡向) ,并按其对生态的影响进行分级;其次对土地利用类型、坡度、坡向进行综合优先级评价;最后在IDRI SI软件中建立生态恢复耗费表面模型。随后通过景观功能分区和生态廊道(这些廊道可组成一个生态网络)的构建,探讨了本小流域土地利用空间格局优化的途径和生态恢复模式。 相似文献
13.
MushtakTalibJabbar 《中国地质大学学报(英文版)》2003,14(4):356-362
Satellite image data and thematic map data were used to provide comprehensive views of surface-bound conditions such as soil and vegetation degradation. The current work applies a computerized parametric methodology, developed by FAO, UNEP and UNESCO to assess and evaluate soil degradation at 1 : 250 000 mapping scale. The study area is located in the arid and semi-arid zone of the northern part of Shaanxi Province in China, a region with considerable agricultural potential; Landsat TM images were utilized to provide recent data on land cover and use of the area. ARC/INFO and Arc-View softwares were used to manage and manipulate thematic data, to process satellite images, and tabular data source. ER mapper software is utilized to derive the normalized difference vegetation index (ND VI) values while field data to estimate soil erodibility (SE) factor. A system is established for rating soil parameters, slope, climate factor and human factor activity. The rating values serve as inputs into a modified universal soil loss equation (USLE) to calculate the present state and risk for soil degradation processes, namely soil wind erosion. The produced maps and tabular data show the risk and the present status of different soil degradation processes. The study area, in general, is exposed to high risk of wind erosion and high hazards of water erosion. Several desertification maps were produced, which reflect the desertification types persisting in the study area. Wind erosion, water erosion, vegetation degradation,physical degradation and salinization are the basic desertification maps, and others are combinations of these basic maps. In terms of statistic analysis, 33.75 % of the total land area (120. 330 0 ha) is considered as sand or sand dune, and not included in our analysis of desertification. About 29. 41% of the total land area has slight or moderate desertification and 37. 465 % is facing severe desertification. 相似文献
14.
Comprehensive evaluation and indicator system of land desertification in the Heihe River Basin 总被引：1，自引：0，他引：1
Two landscape evaluation approaches, an integrated model and an ecological analysis method, based on landscape elements and environmental quality, respectively, were used to describe land desertification in the Heihe River Basin of northwestern China, by evaluating the current state of the local ecosystems and environment. Based on national water-quality criteria and fuzzy cluster analysis methods, surface water quality was divided into 5 grades with corresponding evaluation scores (evaluation rating threshold of water pollution), while groundwater quality was divided into 5 grades based on salinity and solute chemistry. For grassland ecosystems, grass yield (biomass) and types were the main indicators used. The soil component was described according to factors including its nutrient content, thickness, texture and degree of desertification, for a total of 11 evaluation indicators. Total vegetation cover is one of the 5 indicators chosen to describe the plant ecosystem. Based on conditions currently prevailing in the study region, evaluation factors such as total output value of agricultural, industrial, forestry and animal husbandry activities, the ratio of irrigation area to farmland area, the mean output return per unit area farmland, the level of education and per capital income were selected among others to characterize the social and economic situation. In total, 32 typical environment evaluation factors were selected, classifying land desertification in the region into four zones. 相似文献
15.
基于福建省地质灾害调查成果数据库,对福建省内滑坡的致滑地质环境背景因子分别进行描述统计分析和CF概率模型计算,筛选出滑坡致滑关键地质环境背景因子,按敏感程度从高到低分别为滑坡所在位置高程、斜坡坡度、土层厚度和基岩岩性。 相似文献
16.
土地石漠化概念与分级问题再探讨 总被引：8，自引：1，他引：7
针对前人研究中将石漠化发生的地域限定在亚热带,将发生的时间限定在人类历史时期,将发生的原因均归结为人为不合理的经济活动,而忽视了石漠化可能发生的其它地域、其它时期和其它成因等问题,对土地石漠化概念作了修正。认为土地石漠化是在湿润、半湿润气候环境和岩溶环境中,由于人类活动和/或气候变化等因素作用,造成地表植被退化、土壤侵蚀、地表水流失、基岩裸露,形成类似石质荒漠景观的土地退化过程,并对其内涵作出释义。在此基础上依据生态基准面的理论,以坡面形态、溶蚀岩溶地貌形态、基岩出露率、土壤厚度和土被覆盖度、土壤侵蚀程度、植被覆盖率和植物种群、土地利用类型等为景观指征,将石漠化土地分为轻度、中度、重度和极重度4个等级,并以粤北岩溶山区为例,拟定了区域性石漠化土地分级及其综合景观指征。 相似文献
17.
新疆焉耆盆地绿洲水盐双梯度下天然植被多样性分异特征 总被引：2，自引：1，他引：1
通过对焉耆盆地河畔带、荒漠带、湖畔带土壤水盐及地下水位和天然植被关系的分析,研究了干旱绿洲水盐过程与分异天然植被生长和绿洲生态的影响.结果表明:绿洲天然植被生物多样性取决水盐双梯度影响,盐分不断向湖畔积聚是引起焉耆盆地湖畔生态系统生境恶化的主导因子.绿洲内部河畔带物种多样性与地下水埋深关系表明,在埋深1.5m区域,随着地下水埋深的加大,物种多样性减少;在埋深1.5～3m区域内,随着地下水埋深加大,其物种多样性在增加;而当埋深在3～4m之间时,随着地下水埋深的加大,植物多样性呈明显减少趋势;而在埋深4m区域内,多样性指数波动不大.调查表明,随着埋深的变化,地表的天然植被草本、灌木、乔木也呈现明显的分异,地下水水盐条件制约植被分布、生存和演替,各种植被类型适应不同的地下水位和盐分特征. 相似文献
18.
岩溶土壤的生态地球化学特征及其指示意义——以贵州贞丰—关岭岩溶石山地区为例 总被引：18，自引：0，他引：18
岩溶石山地区土壤退化与恢复的成因和机理一直是近年来土壤学和生态学研究的热点。以贵州西南部贞丰—关岭岩溶石山区为对象，选择了区内退化地、农用地、恢复地等生态样块以及与未退化地为对照，采集了其中的表层和亚表层土壤，分别进行了土壤的养分库量、微生物活性与功能和土壤酶活性等化学分析。研究表明土壤养分库是土壤中微生物活性基础，微生物量碳随土壤养分库容的退化或恢复而相应变化，退化岩溶地植被恢复3~6年后，主要养分总库容得到明显恢复(恢复程度55%~65%)，因而带动了微生物量碳的恢复（平均恢复程度60%以上），但养分的活性（有效磷）、微生物的功能（呼吸熵及土壤脲酶和磷酸酶活性）并没有得到相应程度的恢复（平均恢复程度仅在25%~40%）。这些结果提示，限制性养分活性和微生物功能的恢复是植被恢复下生态系统健康水平的重要指示。因此，在分析岩溶土壤和生态系统退化过程的本质以及评价生态恢复的效应时，不仅应将微生物量碳和总养分库指标作为岩溶土壤退化恢复的指标，更应将微生物区系的质量和功能指标纳入关键评价内容。 相似文献
19.
Ian A. Simpson Garar Gumundsson Amanda M. Thomson Jonathan Cluett 《Geoarchaeology》2004,19(5):471-502
This paper assesses the contribution of historical and traditional winter grazing to long‐term land degradation in northeast Iceland. To do so, indicators of soil erosion from two contrasting historical winter grazing areas, set in a tephrochronological framework, are compared against their temporal and regional land degradation contexts. The observations made indicate distinctive and different landscape responses to historical winter grazing depending on location. In both study areas, there is an accelerated level of wind and water erosion with settlement at ca. A.D. 874 through to A.D. 1477. One of these areas had a subsequent reduction in erosion rates to considerably below the regional average, possibly as a result of adaptive land management; the second, more inherently sensitive area, is now subarctic desert. These findings confirm early land management practices as a major factor in Icelandic land degradation, they contribute to explanations of early settlement success and failure, and highlight the significance of historical approaches in addressing contemporary issues of land degradation and conservation responses. © 2004 Wiley Periodicals, Inc. 相似文献
20.
曾昭德 《沉积与特提斯地质》1995,(2):154-161
雅克拉构造位于中国新疆塔里木盆地东北部，沙雅隆起的中段，为一高断块，地处南北侧两个生油拗陷油气运移指向的聚集地带。布于构造上的沙参２井于奥陶系获高产工业油气流。在油气化探工作中，土壤气体测量法属多指标找矿法。在数学地质领域内，因子分析（Ｒ型或Ｑ型）是一种多元统计方法，是用以进行系统分类和成因分类的重要手段。本文通过对雅克拉工区１９５个土壤样品、１３个气测指标（烃类气体１２个，稀有气体１个）进行Ｒ型因子分析，根据因子图解特征，划分因子得分异常区带。以预测该区含油气性。随着地质资料的日益丰富，为进一步对比研究地表异常划分和异常分布特征，作者于１９９３年再次对图形数据进行处理，采用电子计算机成图，对工区异常区带的划分作了修改。 相似文献