共查询到20条相似文献，搜索用时 250 毫秒
1.
多伦县为北方典型的农牧交错区。土地利用是社会与 经济的综合反映,它的变化可引起许多自然和生态过程的变 化,如土壤养分和水分的变化、地表径流与侵蚀以及生物地 球化学循环等。同时,亦可达到控制水土流失和沙漠化,提 高土壤质量的目的。因此,研究近50年来的土地利用变化 与土壤养分的相互关系,为退耕还林还草、退牧还草,合理利 用土地提供科学依据。 (1)50年来土地利用变化与土壤养分的关系。土地利 用结构的变化对土壤养分的影响十分敏感。多伦县总人口 相似文献
2.
黄土丘陵小流域地形和土地利用对土壤水分时空格局的影响 总被引：47，自引：0，他引：47
采用1982～1985年和2002年两个时段的定点观测数据,系统分析了小流域尺度地形和土地利用类型对土壤水分时空格局的影响.结果表明:1)土壤水分变化特征为所有年份农地土壤水分都最大,灌木林地和荒草地较低,林地居中;不同坡向间以阴坡土壤水分最大;而不同坡位间以坡中部土壤水分最大.受降雨和植被耗水的影响,所有土地利用类型中土壤水分在整个生长期表现为降低型.2)在年尺度上表现为干旱年份土地利用类型和坡向对土壤水分的影响较大;而在湿润年份,其影响程度减弱;坡位在干旱和湿润年份对土壤水分的影响都较小.湿润年份,降雨量的增大弱化了地形和土地利用类型对土壤水分时空格局的影响;而干旱年份正好相反.3)在季节尺度上表现为在生长季节的中后期,土壤水分的变异格局主要受坡向影响;而在生长季节的中期,主要受土地利用类型影响;坡位在整个观测时段内影响都较小.4)在不同土壤层次方面特征为土地利用类型对0～20em层次影响较小,而对其他4个深度较大的层次(20～100cm)影响较大,并且5个层次中以40～60cm层次的差异最大;坡向对5个层次土壤水分的变异格局均有明显影响,并呈现随着深度的增加,其影响减弱的趋势;坡位对5个层次的土壤水分变异格局影响均较小. 相似文献
3.
不同演替阶段群落的环境条件有所不同,变化的环境因子驱使群落水平上功能性状和物种适应环境的生态对策改变,然而次生演替过程中群落功能性状和物种生态对策随演替时间的变化规律尚不清楚.本文以云南大黑山喀斯特地区弃耕后处于不同恢复阶段的天然次生林(3年,6年,20年,40年)和老龄林为研究对象,结合不同群落演替阶段的物种特征和群落结构,分析不同演替阶段叶、枝功能性状的变化规律,以及功能性状与环境因子的关系.结果表明:(1)随着演替的进行,土壤养分(除磷外)和水分逐渐增加,土壤容重先下降后趋于稳定,土壤pH变化不明显;比叶面积逐渐下降,叶片干物质含量和潜在最大高度逐渐增大.叶和枝的氮含量呈先下降后上升的趋势,磷含量均下降,N:P总体呈上升趋势.(2)冗余分析表明,演替早期灌木林阶段主要分布在土壤容重高,水分和养分相对匮乏的环境中,植物往往采取高养分含量、高光合速率、短寿命的开放性策略;演替后期乔木林阶段主要分布在土壤水分和养分相对肥沃的环境中,耐阴树种逐渐占据主导地位,植物通常采取低养分含量、低光合速率、长寿命的保守性策略.其中,土壤含水量、全氮含量、容重和有机质是影响喀斯特植物演替过程中功能性状变化的关键环境因子.研究喀斯特植物功能性状与环境因素随演替的变化规律,以及功能性状如何响应环境变化,旨在为今后科学指导人工植物群落构建和防止植被退化提供依据. 相似文献
4.
黄土高原西部土壤水分时空变化模拟研究——以安家坡流域为例 总被引：3，自引：2，他引：1
土壤水作为陆地水循环和水量平衡的一个重要组成部分,在土壤-植被-大气连续体物质与能量转化中起着重要的作用,成为陆面过程研究中的重要参量.选择黄土高原西部的安家坡流域,采用多点长序列观测方法,对该区域土壤水分的时空变化规律进行研究.结果表明:坡向和土地利用类型是小流域土壤水分变异的重要影响因素,得出了不同立地条件下土壤水分的剖面变化与时间的动态规律.在此基础上,利用土壤湿度指数结合主要影响因素预测土壤水分的时空变化,旨在为黄土高原大中尺度的土壤水分模拟提供思路. 相似文献
5.
基于遥感技术的贵州春季土壤水分空间分异研究 总被引：1，自引：0，他引：1
通过对已建立的土壤水分运动模拟模型的校正,使之适合于喀斯特环境的土壤水分运移,并以遥感和GIS技术为依托,反演出贵州省大尺度下的各陆表参数(如: 地表温度、NDVI、气温、日照时数等) ,进而模拟出贵州省土壤水分运动转化过程,定量描述了喀斯特地区土壤水分变化,并对影响土壤水分变化的相关因子进行相关性分析。结果表明: 贵州春季土壤水分含量均值为0. 23mm /mm,次降雨通过蒸散发和下渗等作用在10天左右的时间之后,土壤水分含量及其增长率接近稳定状态,平均土壤水分变化率为1. 16% ;降水量对土壤水分变化的影响程度较其它的气象因子大,与土壤水分的净相关系数较大,是土壤水分变化的最主要的净影响因子;春季贵州省土壤水分空间分布总体上呈现东南、南部较高,而中部,北部、西部地区较低的分布特征,主要原因之一是中北部地区主要以黄壤或水稻土为主,土壤孔隙较大,漏水较为严重,土壤保水性不强。 相似文献
6.
本期以“景观生态学与第四纪研究”为主题登载了 1 4篇学术论文 ,其内容从空间格局与景观变化、土地利用结构与生态过程、农业区的非点源污染与通过景观土壤的养分流的研究 ,到古代或现代人类活动的环境影响 ,多尺度研究与生态地理建模等 ;研究对象从滨海湿地到干旱内流区 ,从西辽河流域到河西走廊 ,从农区到城市 ,从黄土丘陵到长白山和太白山的山地森林。总之 ,从多个侧面反映出景观生态学在中等规模的时空尺度范围内 ,研究空间异质性与生态演化 ,重视格局与过程的特点。景观生态学作为一门植根于生态学和地理学的新兴交叉学科 ,主要研究作… 相似文献
7.
古尔班通古特沙漠与绿洲交错带土地利用变化对土壤特性的影响 总被引：1，自引：1，他引：0
对比研究了古尔班通古特沙漠与绿洲交错带8种土地利用类型的土壤特性变化. 结果表明: 不同土地利用类型的土壤粉砂含量差异性显著(P<0.05). 人类活动干扰的时间越长、 强度越大, 粉砂和极细砂含量越高, 而细砂反之. 在人类活动干扰前期(≤5 a), 土壤养分与干扰时间成反比, 而后(＞5 a)与时间成正比. 不同土地利用类型的土壤养分分为4个等级: 1级为盐碱地, 为最高等级; 2级为生态防护林地、 荒草地和天然灌木林地; 3级为10 a农田地、 5 a菜园地和3 a农田地; 4级为5 a农田地, 为最低等级. 人类活动使得土壤盐分由原来的(盐碱土)上层高、 下层低转为上层低、 下层高. 而且盐分与干扰时间成反比. 土地利用变化的过程中, 土壤盐分与Cl-、 SO42-、 Ca2+、 Mg2+、 K+和Na+离子均成正比, 而与HCO3-离子成反比. 5 a农田地土壤退化指数(-30.58%)最高, 是其他土地利用类型的1.5~3.9倍. 相似文献
8.
洞庭湖区土壤实测碳量的分布规律及其对全球变化的响应 总被引：2，自引：1，他引：1
研究区域土壤碳库的分布特征对于全球变化研究、土壤肥力和生态系统的功能评价具有重要意义。在缺乏长期实测资料情况下,国内外多以模型、第二次土壤普查资料或较稀的实测数据进行研究。文中利用洞庭湖区生态地球化学调查实测数据,研究影响该区土壤碳分布的因素认为区域土壤碳量处于全国的中、高级水平;地质地貌条件是影响土壤无机碳量分布的最重要因素;土壤类型对土壤碳量有影响;本区水土流失强度对表层土壤总有机碳量影响不大;经济林、竹林的土地利用方式及防治土壤潜育化有利于土壤的碳储存;从TOC等沉积的时空演化规律说明,本区环境变化是对全球环境变化的响应,为区域土地利用、促进土壤碳固定及全球环境变化研究提供了依据。 相似文献
9.
针对位于干旱-半干旱气候带的我国西北部矿区生态修复过程中重构层状土壤水分运移规律不清等问题,通过设置不同层状结构土壤进行水分运移入渗试验,监测土壤剖面水分变化,采用Hydrus-1D模拟降雨入渗过程,从土壤水分、水势和水通量3个方面揭示层状土壤水分运移特征,并基于优化后的模型进行情景模拟,探究夹层特征对浅层土壤水分运移的影响。研究结果表明,夹层明显改变了土壤水分的分配与运移过程,土壤水势在夹层界面连续分布,而土壤水分在夹层界面发生突变;虽然黄土夹层和风化砂岩夹层都阻滞了土壤水分的下渗,但其阻滞原理不同,前者表现为黏质夹层渗透性能差导致夹层以上土壤水分滞留,后者归因于粗质夹层土壤基质势小造成水分持留在上部黏质土壤中;根据不同夹层属性的情景模拟结果,提出在风积沙40 cm深度处设置20 cm厚的黄土夹层有利于提高夹层以上土壤水分以供植被利用。研究探明了风积沙区充填黄土对土壤水分运动的影响,并为土壤类型以风积沙和黄土为主的我国西北部矿区在生态修复中的土壤重构方式提供了参考依据。 相似文献
10.
景观格局与水土流失的尺度特征与耦合方法 总被引：11，自引：0，他引：11
景观格局与生态过程的耦合研究是景观生态学研究的核心科学问题,也是综合自然地理学深化和发展的关键.尺度广泛存在于生态学现象中,尺度效应与尺度转换是景观生态学研究面临的挑战,探讨格局与过程之间相互作用机理与尺度特征是为解决尺度问题提供理论依据的必然途径.水土流失作为一种生态过程,是国内外颇为关注的生态问题.依据多种研究手段,在不同尺度上开展景观格局与水土流失的相互关系与尺度特征的研究,在分析景观格局的时空异质性、水土流失的影响因子与尺度效应的基础上,揭示流域景观格局与水土流失的耦合机理,发展尺度转换方法和景观格局-水土流失过程耦合模型,是完善景观生态学的理论基础,是为水土流失区生态建设提供科学依据的重要途径. 相似文献
11.
Progresses and Prospects of the Research on Soil Erosion in Karst Area of Southwest China* 总被引：1，自引：0，他引：1
The karst area of Southwest China is suffering from serious ecological and environmental problems due to soil erosion while the research on soil erosion is not sufficient. Primary achievement was systematically reviewed in this paper in three aspects: erosion characteristics, current researches about erosion on different spatial scales, and key scientific problems. Based on the review, the authors figured out the shortcomings of the existing studies and pointed out the directions on erosion study in southwest China karst region. The results showed that: ① Due to the existence of a dual structure in karst environment including ground and underground erosion, the process of runoff and sediment production on slope scale and confluence and sediment transportation processes on catchment scale were more complex under the unique geological and hydrological backgrounds; ② At present, most researches about erosion mechanism in karst area focus on slope scale and some achievements on quantitative evaluation of erosion factors have been made. Continuous data with high quality about relationship between water and sediment on catchment scale is limited. When data is scarce, river sediment data can be used as an effective way to study soil erosion intensity and spatial-temporal variation in karst area; ③ It is more reasonable to use 50 t/(km2·a) as the grading standard of soil loss tolerance than the previous grading standard of soil erosion intensity. Given the complex relationship between rocky desertification and soil erosion, more quantitative studies about the effects of rocky desertification on soil erosion are still necessary. There are different viewpoints on soil leakage definitions, leakage mechanism and leakage ratios, and new breakthroughs could be achieved by combining different methods and matching multi-scales. In conclusion, in order to further reveal soil erosion laws and establish and revise available regional soil erosion forecasting models for Southwest China karst areas, synchronous test and monitoring on slope, watershed, and channel spatial scales are urgently needed. The results can provide theoretical and technical support for promoting soil and water conservation work for the karst area of Southwest China. 相似文献
12.
Qiuping Huang Jiejun Huang Yunjun Zhan Wei Cui Yanbin Yuan 《Earth Science Informatics》2018,11(4):567-578
Quantifying land use patterns and functions is critical for modeling urban ecological processes, and an emerging challenge is to apply models at multiple spatial scales. Methods of determining the optimum scale of land use patterns are commonly considered using landscape metrics. Landscape metrics are quantitative indicators for analyzing landscape heterogeneity at the landscape level. In this study, due to their widespread use in urban landscape analyses and well-documented effectiveness in quantifying landscape patterns, landscape metrics that represent dominance, shape, fragmentation and connectivity were selected. Five metrics include Patch Density, Contagion, Landscape Shape Index, Aggregation Index and Connectivity. Despite a wide application of landscape metrics for land use studies, the majority mainly focuses on the qualitative analysis of the characteristics of landscape metrics. The previous models are limited in exploring the optimum scale of land use patterns for their lack of quantitation. Therefore, taking the City of Wuhan as an example, the land use unit was treated as a patch, and the landscape pattern metrics at different spatial scales were calculated and compared so as to find the optimum one. Furthermore, a mathematical model of landscape metrics was proposed to quantify the scale effect of urban land use patterns, generating a complementary tool to select the optimum scale. In addition, Analytic Hierarchy Process (AHP) was introduced to determine the respective weights of the chosen landscape metrics in this model. Fractal dimension was ultimately applied to verify the chosen optimum scale of our study region. The results indicated that 60 m is confirmed to be the optimum scale for capturing the spatial variability of land use patterns in this study area. 相似文献
13.
西南喀斯特区土层浅薄、成土速率低等特点决定了其允许土壤流失量小,土壤一旦流失,极难恢复,土壤侵蚀及其造成的石漠化现象已成为制约该区可持续发展最严重的生态环境问题。文章首先明晰西南喀斯特区土壤侵蚀特征,从坡面、小流域和区域三个尺度上系统概括西南喀斯特区土壤侵蚀的相关研究进展。针对当前喀斯特区土壤侵蚀研究野外径流小区、小流域及区域空间尺度数据缺少和相关研究模型限制性强等不足,建议从不同尺度深入研究喀斯特区土壤侵蚀发生发展规律及时空演化格局,并结合高新遥感、地球物理探测技术及模型,同步监测坡面—小流域—区域土壤流失,对土壤侵蚀进行定量评估,结合不同空间尺度土壤侵蚀特征构建系统性水土保持生态恢复治理模式和监测系统评价体系。 相似文献
14.
Studies on denudation processes and soil loss rates can provide insight into the landscape evolution, climate change, and human activities, as well as on land degradation risk. The aims of this study were to analyze the space–time distribution of denudation processes and evaluate the soil loss changes occurred during the period 1955–2016 by using an approach integrating geomorphological, geospatial and modeling analysis. The study area is a representative stream catchment of the Crati Valley (Calabria, southern Italy), which is affected by severe erosion processes. The combined use of aerial photographs interpretation, field survey, geostatistics, and GIS processing has allowed to characterize the types of denudation processes and land use change in space and time. Revised universal soil loss equation implemented in GIS environment was used to estimate the space–time pattern of soil loss and the soil erosion rates for each investigated year. The results showed that from 1955 to 2016, the study area was highly affected by denudation processes, mainly related to landslides and water erosion (slope wash erosion and gully erosion). Comparison of denudation processes maps showed that the total area affected by erosion processes has increased by about 31% and the distribution of geomorphic processes and their space–time evolution resulted from the complex interrelation between geoenvironmental features and human activities. The main land use changes concerned a decrease in areas covered by woodland, scrubland and pasture and an increase in croplands and barren lands that favored erosion processes. The most susceptible areas to soil loss in both years were mapped, and the mean soil loss rates for the study area were 6.33 Mg ha?1 y?1 in 1955 and 10.38 Mg ha?1 y?1 in 2016. Furthermore, the soil loss in 2016 has increased by about 64% compared to 1955. Finally, the results showed that integrating multi-temporal analysis of denudation processes, land use changes and soil loss rates might provide significant information on landscape evolution which supports decision makers in defining soil management and conservation practices. 相似文献
15.
Huading Shi Qingxian Gao Yongqing Qi Jiyuan Liu Yunfeng Hu 《Environmental Earth Sciences》2010,61(4):689-697
The most serious environmental problems of the Mongolian Plateau are land degradation and sand storms caused by wind erosion,
but the evaluation of wind erosion at regional scales has been a difficult process in wind erosion research. In this study,
fuzzy c-means clustering (FCM) was used to assess the spatial pattern of wind erosion hazard on the Mongolian Plateau. By fuzzy clustering
four main wind erosion factors (vegetation cover, average degree of land surface relief, degree of soil dryness and intensity
of wind energy), wind erosion hazard was classified into six grades. Results show that FCM can effectively integrate related
information between wind erosion and environmental factors, which provides the basis for predictive mapping of wind erosion
hazard. Spatial patterns of wind erosion hazard indicate a gradual trend of increasing hazard in the Mongolian Plateau from
east to west. Similar patterns were also found in NDVI and soil dryness, indicating that soil moisture and vegetation are
the most important factors in the formation of wind erosion hazard. In addition, the distribution of different levels of wind
erosion hazard is basically consistent with the regional distribution of landscape vegetation types in the Mongolian Plateau. 相似文献
16.
地域分异是地球表层大小不等、内部具有一定相似性地段之间的相互分化以及由此产生的差异。为了研究不同区位土壤侵蚀问题，从土壤生态景观及系统论出发，运用地质学、地理学、景观生态学、环境学的理论和研究方法，研究湖北省土壤侵蚀景观空间格局及其驱动因子，使土壤侵蚀问题研究提高到一个新的水平。湖北省土壤侵蚀景观具有南北分带、东西分区，为一不对称的断块一环组合，土壤流呈现向长江、江汉盆地中心轴带辐聚、单流向特点。景观空间异质性形成的首要驱动因子是大地构造背景，以房县一襄樊一广济断裂带为界，南北两侧地壳物质组成和构造发展史存在较明显的差异，现代气候带、降雨量、温热程度及土地利用等差异，造成了湖北省区域土壤地理、土壤生态的分异，形成湖北省土壤生态带、区具有南北分带，东西分区的宏观格局；其次大兴安岭一武陵山深部构造陡变带两侧新构造运动强度差异、大别造山带构造强烈隆升，导致土壤侵蚀强度的西强东弱、南北强中间弱的态势；成土母岩差异性决定了土壤可蚀性的多变；空间上“土壤侵蚀内城区”分布在湖北省的周边地区，经济贫困、管理落后，这一地区的经济水平与水土流失间形成“自反馈作用”，这一现象在我国水土保持、生态建设工作中应该引起重视。 相似文献
17.
This study was taken up to investigate the effects of landscape patterns on the soil erosion processes in a mountain–basin watershed. The revised universal soil loss equation and sediment delivery distribution models were used to estimate the soil erosion processes. The landscape patterns include the landscape metrics at the landscape level, landscape composition and configuration indicators on the basis of source–sink landscape theory. In the study area, the grassland, bare land, farmland and construction land were the sediment-source landscape; the forest and shrub were the sediment-sink landscape. The correlation analysis results showed that the soil erosion processes were significantly associated with the landscape patterns of the study area. At the landscape level, fragmentation metric was positively correlated with soil erosion; diversity metric was negatively related to soil erosion and sediment yield at the sub-basin scale. Among the source–sink landscape composition and configuration indicators, the composition indicator was positively correlated with soil erosion rate and sediment yield. In the configuration landscape indices, the shape index was negatively correlated with soil erosion rate and sediment yield; the fragmentation index was positively correlated with soil erosion rate and negatively correlated with sediment delivery rate. These results indicated that the optimization measures, such as increase in the area, connectivity and regularity of sediment-sink landscape, or decrease in the proportion, connectivity and regularity of sediment-source landscape, were favorable for soil conservation. Furthermore, the landscape indicators based on the source–sink theory could provide more information for landscape pattern optimization to reduce soil erosion. 相似文献
18.
土壤裸露是水土流失具体的空间表现,同时又是导致进一步水土流失的重要因素。由人类和自然相互作用下形成的景观格局对土壤裸露具有深刻的影响。为深入探讨二者间的内部联系,文章选定位于黄土高原的延安市宝塔区为研究区,分别就景观格局的类型组成和空间结构,分析其与土壤裸露的关系。研究结果可知人为活动强度较大的区域土壤裸露程度较高,在景观类型上,表现出滩地、农村居民点、其他建设用地、低覆盖度草地及山区旱地等景观类型的土壤裸露值较高,另外,从景观组成来看,农牧组成为主的流域土壤裸露值明显高于其他流域;通过景观空间结构与土壤裸露的关系分析,可知个体单元型态、空间构型以及整体多样性等景观空间结构特征,均对土壤裸露程度具有不同大小的指示意义,其中又以景观聚集度及平均斑块面积与土壤裸露程度有强烈负相关。 相似文献
19.
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
20.
以封丘地区典型的4种土地利用类型(传统耕作地、免耕地、金银花地和杨树林地)为例,系统研究了不同土地利用方式下土壤入渗特性的空间变异强度、空间变异结构及其主要变异源。结果表明,频繁的耕作会降低土壤异质性,弱化土壤特性空间变异结构,扰动较小的免耕地和金银花地的土壤入渗特性则具有相对明显的空间变异结构,扰动最小的杨树林地土壤的入渗特性具有最为明显的空间变异结构和最小的变程。容重、有机质含量和初始含水量是耕作地入渗的最主要变异源,初始含水量则是金银花地入渗的唯一显著性变异源;杨树林地入渗变异的主要变异源是有机质和初始含水量;影响免耕地入渗特性变异的变异源并不显著。在有些情况下,水温也可能成为入渗特性空间变异研究的重要干扰因素。 相似文献