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1.
三峡库区王家桥小流域土壤侵蚀因子初步研究   总被引:8,自引:0,他引:8  
通过对王家桥小流域土壤,降雨,植被和地形等因子的分析,探讨了土壤抗侵蚀性能,分析了坡面侵蚀与各影响因子间的关系,建立了基于降雨基础上的全流域输沙幂函数回归方程。结果表明,本地区土壤因具有较强的渗透性,抗冲,抗蚀和抗剪切破坏的能力,而使其保持较小的可侵蚀性;坡面侵蚀中的主要影响因素是雨强和径流量(或降雨量)的大小;流域内土壤侵蚀的形式主要表现为暴雨作用下的重力侵蚀,在影响土壤侵蚀的诸多因子中降雨是关键性的,它的强度和年分布对年侵蚀模数的大小具有决定性作用。同时,通过分析各种雨强(平均雨强,最大雨强,最大15分钟雨强,最大30分钟雨强,最大60分钟雨强)对土壤侵蚀量的影响,结果表明,虽然最大60分钟雨强具有最优相关性,但在多元回归方程中,采用最大30分钟雨强回归效果最佳。  相似文献   

2.
漫湾水电站是澜沧江水能梯级开发的第一个干流大型水电站,加强库区水土流失治理与监督监测尤为必要,而降雨侵蚀力的时空分布规律研究则是实现区域土壤侵蚀定量监测预报的重要基础。根据有关降雨侵蚀力的计算方法,利用漫湾电站库区4个测站1980~2000年的逐月平均降雨资料,估算了其降雨侵蚀力R值的时空分布规律及其变化特征。结果表明:漫湾电站库区多年平均降雨侵蚀力在1 9336~3 9727 MJ·mm/hm2·h;R值的年内变化显著,且较大值集中分布在雨季的5月~10月,平均R值占全年的867%,尤其6~8月连续3个月的降雨侵蚀力平均占全年侵蚀力的一半以上;R值的年际变化显示20世纪90年代漫湾电站库区降雨侵蚀力比80年代平均增加2835 MJ·mm/hm2·h;R值的空间分布上以凤庆站点的年降雨侵蚀力最大;南涧站点的年降雨侵蚀力最小,但是其年际波动幅度较大。全面地分析了漫湾电站库区降雨侵蚀力R值的时空变化特征,为该地区有效防止与监测水土流失情况、更好地安置水电站工程移民提供参考。  相似文献   

3.
以三峡库区腹地5个区县为研究区,以1988、2000、2010和2015年4期遥感数据为数据源,借助RS和GIS技术,得到研究区土壤侵蚀数据,采用土壤侵蚀综合指数,从区域尺度、乡镇尺度分析三峡库区腹地土壤侵蚀时空演变规律及其差异性。结果表明:(1)在27a间,区域尺度的土壤侵蚀状况呈现波动性演变,2000年以前研究区土壤侵蚀状况在恶化,而2000年以后侵蚀状况逐渐好转并趋于稳定;(2)在乡镇尺度上,进一步分异,出现4种演变类型:持续性变好、持续性变差、波动性变好、波动性变差;主体演变类型与整体大体一致,但在云阳县和长江沿岸存在与整体相反的演变类型;(3)侵蚀状况始终严重或持续性变差的12个乡镇为治理重点区域,而波动性变差的24个乡镇为治理的次重点区域。研究结果有助于该区域水土流失的精准治理。 关键词: 土壤侵蚀演变;土壤侵蚀综合指数;多尺度研究;三峡库区腹地  相似文献   

4.
以三峡地区的乐天溪流域为例,利用多时相Landsat TM/ETM影像、文献和野外调查资料研究了替代能源对流域土地利用和土壤侵蚀的影响。通过几年替代能源措施实施,乐天溪流域林草覆盖率由1997年的80.6%增加到2002年的83.2%;不仅林草覆盖率增长,而且质量也有较大提高,覆盖度较高的林地和灌丛面积增幅达18.1%和9.1%,相反疏林面积减少37.9%。强度、中度和轻度侵蚀面积分别减少了4.6 km2、26.4 km2和11.5 km2;流域的土壤侵蚀总量由507 259t减至371 592 t,减少26.8%;流域的平均侵蚀模数由1 241 t/km2减至909 t/km2。  相似文献   

5.
根据国际上对于荒漠化概念的新说明以及由联合国环境规划署所资助的《中国荒漠化 (土地退化 )防治研究》课题报告中确定的荒漠化定义 ,荒漠化概念的内涵包括 :1)以土地退化为本质 ;2 )与人类活动相关联 ;3)以荒漠化景观为标志 ;4 )以脆弱生态环境为背景。因此我国的荒漠化类型除了风蚀作用形成的沙质荒漠化外 ,还有水蚀作用形成的土质荒漠化和石质荒漠化 ;荒漠化防治的重点区域除北方干旱、半干旱和半湿润地区以外 ,也包括南方湿润地区的红壤丘陵区和石质山区。其中属于水蚀荒漠化和土质荒漠化的红色荒漠化就是指我国南方红壤丘陵区在人类不合理经济活动和脆弱生态环境相互作用背景下 ,以流水侵蚀为主导作用而形成、以地表出现劣地为标志的严重土地退化。鉴于我国南方红色荒漠化现象在我国现实存在中的客观性、在全球变化中的特殊性以及在理论概念上的模糊性 ,有必要对其进行深入研究  相似文献   

6.
中国荒漠化灾害评估及其经济价值核算   总被引:24,自引:0,他引:24  
本文对我国荒漠化的现状和危害进行了系统分析。运用货币估值方法对最新公布的荒漠化和水土流失监测数据进行计算,得出我国荒漠化危害的直接经济损失约642亿元/年,平均每天损失1.76亿元;其中几种主要荒漠化类型造成的经济损失分别为:水力侵蚀400亿元,风力侵蚀36亿元,盐渍化及有机质丢失造成的损失约186亿元;据估算每年因沙尘暴造成的经济损失超过13亿元,荒漠化及其衍生危害造成的间接经济损失约2889亿元/年。  相似文献   

7.
由美国耶鲁大学和哥伦比亚大学合作开发的环境可持续指数(Environmental Sustainability Index,ESI)可用以衡量一个国家或地区能为其后代人保持良好环境状态的能力,也可考虑作为环境决策的基础之一。其研究处在现有环境可持续指标体系研究的国际前沿水平。本文简介了ESI的进展与内涵;阐述了2005ESI的指标设置、方法学及其改进;列举了2005ESI用于146个国家或地区环境可持续性的测试结果及其政策建议,分析了中国得分很低的原因,最后,概要评述了ESI的特点和进一步发展方向。  相似文献   

8.
GIS支持下土壤侵蚀潜在危险度的分级研究   总被引:21,自引:0,他引:21  
根据土壤侵蚀特点,在IDRISI地理信息系统(GIS)支持下,研究设计了小流域空间与属性数据库的建设,在GIS系统支持下可有效地实现区域土壤侵蚀潜在危险的分级及其空间分析。首先,采用侵蚀预报的数学模型来估算土壤侵蚀星,用土壤详查资料编制土层厚度和土壤容重图,然后,由土壤年均侵蚀量,土层厚度和土壤容重得到土壤抗蚀年限图,按水利部标准将土壤侵蚀潜在危险度分为5级。最后,为表明某一地区或地类土壤侵蚀潜在危险的大小,还提出了土壤侵蚀潜在危险指数(SEPDI)。以三峡库区的王家桥小流域为例进行了研究,并且分析了其空间分布特点。  相似文献   

9.
汉江上游是南水北调中线水源地,流域生态环境建设是保障水源地水质安全的关键。针对上游流域水环境污染、土地利用以及水土流失等重大生态环境问题,结合流域数字高程模型及水质调查对其进行了系统分析。结果表明:(1)丹江流域、库区流域及汉中盆地水质较差,CODMn和氨氮成为水源区主要污染物;(2)各子流域区植被覆盖占各自面积的712%~957%,表明流域植被覆盖较好,但沿河岸100 m范围内农业用地占292%~434%,且多为坡耕地;(3)流域水土流失严重,2000年左右流域侵蚀图显示汉江源头、秦岭南及大巴山北均出现了大片年均侵蚀模数>2 200 t/km2的区域,且有日益增强的趋势。提出加大水环境污染整治力度、加强农业用肥管理及河岸带建设、水土保持建设以及加强流域水环境及水土保持监测和科研工作等对策。  相似文献   

10.
长江口九段沙上沙典型潮滩年周期冲淤变化分析   总被引:1,自引:0,他引:1  
根据2006年6月-2007年6月长江口九段沙上沙两固定断面逐月滩面高程测量结果,并结合同期表层悬沙浓度逐日观测资料,对潮滩的短周期冲淤变化过程及其演变特征进行了分析。结果表明:①潮滩具有明显的季节性冲淤循环规律,呈现“洪淤枯冲”的变化特征,其垂直冲淤量与同期提前一周长江大通径流量呈较好相关关系,相关系数达0.61;②“碧利斯”台风导致滩面平均蚀低6.4cm,最大蚀深20.2cm,其侵蚀量占年侵蚀总量近五成;③有人工抛石堤庇护的潮滩相对于自然潮滩,其冲淤变化量值和幅度均较小,而其相对高程与悬沙浓度间的线性相关系数变幅大,表明人工抛石堤具有一定的保滩功能,但其同时也改变了潮滩自然发育演变过程和规律。分析认为:上述潮滩年周期冲淤演变特征是在人为因素影响基础上,暴风浪和流域来水来沙综合作用的体现。  相似文献   

11.
Total concentrations of Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Pb and Zn have been estimated in soil (A-horizon) and in leaves and stem samples of two Mediterranean species (Nerium oleander L. and Pinus pinea L.) growing in an industrial area in Spain (Huelva). Both species showed a different behaviour for the elements studied. Bark and leaves of both species acted as excluders of Al, Ba, Cr, Fe and Pb, N. oleander acted as indicator of Cu and Zn and, needles and bark of P. pinea behaved as accumulators of Cu. The enrichment ratio data indicated that Cu in soil and plant was enhanced with anthropogenic activities, with industrial activities being the primary contributor for Cu. All the other elements studied were controlled by natural source variations, but Pb could also be anthropogenically enhanced. Wood did not accumulate pollutants, with the translocation from bark being rather reduced. Uptake patterns of metals into foliage and bark tissues were more or less the same in both species for almost all the studied elements, which indicates that both plant parts could be indifferently used as biomonitors.  相似文献   

12.
The beneficial role of mycorrhizal association on plant nutrition and water supply is well-known, however, very little information exists with respect to the availability of radionuclides. We have measured the effect of controlled mycorrhizal association on the root uptake from soil and accumulation in leaves of three radionuclides. The radionuclides have contrasting chemical and biological properties: Cs is strongly adsorbed on soil, has no biological role and is a close analogue of potassium; Sr is less strongly adsorbed on soil and behaves very similarly to calcium; and Tc is very mobile in soil as pertechnetate, but immobilised when reduced to Tc(IV), it is also considered to be easily assimilated by biological systems. We found that mycorrhizal association had no effect on root-to-needle transfer of Cs, but increased root uptake and that this increase could not be explained by improved potassium nutrition. In contrast, the symbiotic relation decreased Tc soil-to-needle transfer, but this resulted from complex dynamics of root uptake and rapid immobilisation of Tc in soil. No effect of mycorrhizal association on Sr, like its stable analogue Ca, was observed. The addition of a phytotoxic metal, Cu, inhibited mycorrhizal association, thus eliminating the effects observed for non-contaminated plant-fungus couples, but had no additional effect on radionuclide dynamics.  相似文献   

13.
挺水植物水田芥对镉的积累特性研究   总被引:2,自引:0,他引:2  
通过前期的初步研究发现,挺水植物水田芥(Nasturtium officinale R.Br.)地上部分镉含量超过了超富集植物的临界值(100mg/kg),可能是镉超富集植物。为进一步了解水田芥在不同镉浓度梯度条件下的镉积累特性,通过盆栽试验研究了不同土壤镉浓度(0、25、50、75、100mg/kg)对水田芥生长特性、镉耐性和镉积累特性的影响。结果表明:随土壤镉浓度的增加,水田芥根系和地上部分镉含量增大,分枝数量、根系生物量、地上部分生物量、抗性系数及叶绿素SPAD值均呈降低的趋势。当土壤镉浓度大于0mg/kg时,随着土壤镉浓度的增加,水田芥的根冠比呈增加的趋势。土壤镉浓度为50~100mg/kg时,水田芥地上部分镉含量均大于100mg/kg,最大值为214.84mg/kg(土壤镉浓度为100mg/kg),地上部分富集系数(BCF)大于1,但转运系数(TF)小于1。在土壤镉浓度为50mg/kg时,水田芥地上部分镉积累量达到最大值,为192.233μg/株。因此,水田芥是一种镉富集植物,适合用于土壤镉污染浓度在50mg/kg以内的水田修复。  相似文献   

14.
This study aims to screen plant species native to Taiwan that could be used to eliminate (137)Cs radionuclides from contaminated soil. Four kinds of vegetables and two kinds of plants known as green manures were used for the screening. The test plants were cultivated in (137)Cs-contaminated soil and amended soil which is a mixture of the contaminated one with a horticultural soil. The plant with the highest (137)Cs transfer factor was used for further examination on the effects of K addition on the transfer of (137)Cs from the soils to the plant. Experimental results revealed that plants cultivated in the amended soil produced more biomass than those in the contaminated soil. Rape exhibited the highest production of aboveground parts, and had the highest (137)Cs transfer factor among all the tested plants. The transfer of (137)Cs to the rape grown in the soil to which 100 ppm KCl commonly used in local fertilizers had been added, were restrained. Results of this study indicated that rape, a popular green manure in Taiwan, could remedy (137)Cs-contaminated soil.  相似文献   

15.
为了解秦岭山地土壤侵蚀及土壤保持生态服务功能的空间分布特征,采用InVEST 土壤保持模型,从研究区、流域、县域3个尺度,对其潜在与实际土壤侵蚀量进行计算,在此基础上进一步应用该模型量化研究区土壤保持生态服务价值,得到土壤保持服务价值空间分布图。研究结果表明:(1)2012年秦岭山地潜在与实际土壤侵蚀量分别为4588×108 t、152×108 t,五大流域和各县区以轻度侵蚀和中度侵蚀为主,较为严重的地区为汉江流域南部紫阳县6323 t/(hm2[DK]·a)[JP2]和岚皋县5869 t/(hm2[DK]·a),属强烈侵蚀。(2)全区土壤保持总量4337×108 t,[JP]其中泥沙持留量143×108 t,单位面积土壤保持量为71979 t/(hm2[DK]·a);减少泥沙疏浚工程和水质治理花费的土壤保持服务价值共计4184亿元。各县区土壤保持服务价值量在001亿元至475亿元不等,价值量在096~191亿元之间的县区占全区的4413%,其次为191~285亿元(2522%)。(3)对于秦岭山地土壤侵蚀的防治及其生态效益的建设,保证林地面积的绝对优势是首要条件;对于大于25°的坡耕地,应继续推行还林还草政策  相似文献   

16.
Modeling soil organic matter dynamics as affected by soil water erosion   总被引:6,自引:0,他引:6  
Soil organic carbon (SOC) stock is an important component of the global carbon (C) cycle, which has the potential to influence global climate. In this paper we presented an overview of soil organic matter (SOM) models in the context of soil erosion and discussed basic processes driving erosion-induced SOC loss. Although the mechanism of this loss is poorly understood, erosion influences SOC in two ways: redistribution of C within the watershed or ecosystem, and loss of C to the atmosphere. Erosion disperses soil, altering its microbiological activity as well as water, air and nutrient regimes. This, along with sediment enrichment, has an impact on greenhouse gas emission from soil. For most of agricultural settings, field studies suggest that cultivation along with soil erosion are the primary reasons for SOC loss. Tracing the fate of eroded C is a challenging task. Modeling is the approach taken most often. In this paper we discuss approaches used in various SOC models to assess erosion-induced C loss from soil in agricultural ecosystems. An example with Century model applied to meadow and corn-soybean rotation under chisel-till demonstrated the model's ability to respond well to different erosion scenarios. It was estimated that at soil loss rate of 10 t ha(-1) year(-1) (value often considered a threshold for maintaining productivity) 19% of the total SOC loss would be attributed to erosion after 90 years of cultivation.  相似文献   

17.
For the past 20 years, the National Foundation for Agricultural Research in Crete and the School of Agricultural Technology of the Technological and Educational Institute of Crete have been involved in a number of research and development activities, related to the production and evaluation of compost derived from a variety of local solid, mainly agricultural organic wastes. Materials such as olive press cake, olive tree leaves (OTL) and branches, vine branches (VB), pressed grape skins (PGS), pig manure (PM), sewage sludge and the organic fraction of municipal solid waste (OFMSW) have been evaluated for their behaviour during composting, their compatibility in mixtures and the quality of the end product. The quality evaluation included both a detailed physiochemical (pH, electrical conductivity (EC), nutrients concentration, heavy metal concentration, etc.) and biological analyses (pathogenic microorganisms). It also included an agronomic evaluation, in which composts were used either as a soil amendment or as a component for substrates in open air or covered (greenhouse) cultivation mainly of local vegetables (tomatoes, cucumbers, etc.). All materials were composted successfully, especially when mixed. The end products contained large amounts of organic matter, usually combined with an increased EC value. Pressed grape skins should be considered as the ideal raw material, producing a high quality compost, with the lowest EC value (1.57 mS cm(-1)) and the largest organic matter concentration (84.50%), compared to all other materials. When any of the produced compost was used in a ratio of 30% by volume (v/v), it increased plant growth, whereas in larger volumes, it presented phytotoxic behaviour, inhibiting both root and shoot development.  相似文献   

18.
The accumulation and long-term decline of radiocesium contamination in tropical plant species was studied through measurements of gamma-ray spectra from pomegranate (Punica granatum) and chili pepper (Capsicum fructescens) trees. The plants were originally grown at a (137)Cs contaminated site (where a radiological accident occurred in the city of Goiania, Brazil, in 1987), and transplanted to uncontaminated soil, so that the main source of contamination of the new leaves and fruits would be the fraction of the available radiocesium in the body of the plants. Measurements of (137)Cs and (40)K concentrations along the roots, main trunk, twigs, leaves and fruits before and after the transplant process of both plant species indicated a direct competition between Cs and K ions, suggesting that these elements could have a common accumulation mechanism. Cesium transfer factors from soil to pomegranate, green and red chili pepper fruits were evaluated as 0.4 +/- 0.1, 0.06 +/- 0.01 and 0.05 +/- 0.01, respectively. Biological half-life values due to (137)Cs translocation from the tree reservoir (BHL(T)) were calculated as 0.30 years for pomegranate, 0.12 years and 0.07 years for red and green peppers, respectively.  相似文献   

19.
〖HTSS〗洞庭湖土壤镉污染严重,蒌蒿(Artemisia selengensis L.)是在洞庭湖湿地新发现的一种对镉具有较强富集能力的优势植物,已证实该种植物对土壤中的镉具有较好的修复效果和潜能,将来可作为洞庭湖土壤镉污染的理想修复材料。以南洞庭湖Cd污染土壤为栽培基质,分别在蒌蒿幼苗期、成株期添加EDTA等7种螯合剂和调控物质,研究了不同添加物对蒌蒿生长状况及Cd富集效果的影响。结果表明,HEDTA、EDTA、DTPA等3种螯合剂不同程度地降低了蒌蒿地上部分的生物量,但增加了土壤中有效态Cd的含量,使蒌蒿茎叶中Cd的富集浓度分别上升了35.5%、984%、421%,可显著提高蒌蒿的修复效果;生石灰的添加则使土壤有效态Cd明显减少,抑制了蒌蒿对Cd的富集;有机腐殖质和复合肥的施加虽促进了蒌蒿生长,但未对其富集效果产生显著影响;幼苗期施加调控物质,在植株生物量、Cd富集浓度及土壤有效态Cd含量等方面造成的影响均大于成株期  相似文献   

20.
The leaves of 22 woody and herbaceous plant species growing in urban ecosystems of Kalinigrad were analyzed for the total contents of water-soluble antioxidants (TAC) and polyphenol contents. The soils of test plots were assayed for lead contents in the accumulative horizon. A significant excess over the background Pb level was revealed in soil samples from residential and industrial/utility areas (42% of the city territory), and TAC in plant tissues was found to decrease with an increase in Pb concentration in the soil. The role of polyphenols in forming the antioxidant potential of urban plants growing under conditions of technogenic soil pollution was evaluated. Based on cluster analysis of the water-soluble antioxidant and polyphenol accumulation patterns, the plants were classified into four groups. The results of this study may be used for comprehensive assessment of the resilience of urban plants to anthropogenic impact and improvement of the approaches and methods for monitoring industrial pollution in urban areas.  相似文献   

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