首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
沙棘及其混交林减少径流泥沙的作用突出,但结构和混交模式不同所发挥的水保作用大小不同。沙棘林生长季各月消耗利用水分的强度不同。在整个生长季,5月末0-500cm土层平均含水率最低,为5.1%;10月末最高,达8.8%,沙棘林对土壤水分的利用强度受林龄影响,8龄沙棘林年消耗土壤贮水231.2mm,应进行平茬,平茬后第3年末,土壤水分恢复深度达160cm,含水率为10.3%-14.6%,沙棘林具有削减坡位对土壤水分影响的作用,沙棘及其混交林对土壤水分的利用强度相似,林地存在土壤干层现象。  相似文献   

2.
陕北黄土区雨季后山地枣林土壤水分动态变化研究   总被引:1,自引:0,他引:1  
选取陕北延川县齐家山红枣试验基地枣林地、苹果林地和撂荒草地为研究对象进行土壤水分动态变化研究,结果表明:①不同坡位、不同坡向和不同整地方式的枣林地土壤水分存在显著差异;其中,研究区下坡位土壤水分最高,为14.19%;阴坡土壤水分最高,为14.19%;水平阶整地枣林土壤水分显著高于原状坡。②研究区不同植被类型间土壤水分垂直变化趋势基本一致。枣林地土壤水分最高,为11.49%;不同植被类型0~100 cm土壤贮水量依次表现为枣林地(144.76 mm) > 苹果林地(124.19 mm) > 撂荒草地(72.20 mm)。③不同植被类型土壤贮水亏缺度存在差异。雨季前,0~20 cm土层亏缺度最小,平均亏缺度表现为撂荒草地 > 枣林 > 苹果林;雨季后,土壤水分亏缺度表现为撂荒草地 > 苹果 > 枣林,除枣林地外均高于雨季前土壤水分亏缺度。④雨季后,研究区3种植被类型0~20 cm土层土壤水分亏缺加剧;20~100 cm土层中,枣林土壤贮水补偿度为正值,土壤水分得到补偿,但最高仅为22.95%,枣林土壤水分仍处于亏缺状态并未完全恢复;苹果林地土壤贮水补偿度则为负值,表明土壤水分亏缺进一步加剧;撂荒草地土壤水分补偿度基本维持在0左右,土壤水分亏缺没有持续恶化。  相似文献   

3.
Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO3 and NH4 were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development.  相似文献   

4.
为在PrinceRupert林区的“亚北方”部分建立生态立地质量与森林生产力的联系,对从93个小杆松林分和77个白云杉林分获得的数据进行了分析.所研究的林分处于两个气候状况、8个土壤水分状况以及5个土壤养分状况.这些气候、土壤水分和养分状况被视为等级变量用于林地分类和回归分析.小杆松和白云杉的立地指数随土壤水分和养分状况变化而变化,但不依赖于气候变化.与土壤水分相关的变化格局对两个种来说很相似,但与土壤养分相关的变化格局则全然不同.在所建立的5类回归模型中,土壤小区模型对于两个种都显示出立地指数与土壤水分和养分状况具有很强的相互关系(R2>0.80,SEE≤1.6m).可以认为土壤水分和养分的等级度量在大范围内可作为小杆松和白云杉立地指数的预测预报因子.  相似文献   

5.
森林土壤水分作为物质与能量循环的载体影响林木生长与发育,并通过影响水分在陆气之间的循环与分配影响区域气候。基于我国不同气候带的9个森林生态系统定位观测站的长期观测数据,探究了2005-2016年中国典型森林生态系统土壤水分的空间分异及其时间动态,并进一步分析了影响其时空分异的环境因素。主要研究结论如下:(1)9个森林生态系统的土壤水分多年均值介于12.45%-36.30%之间,空间上呈现中温带、亚热带、热带土壤水分较高,暖温带土壤水分较低的分布特征。降水蒸散差(降水与蒸散的差值)可以解释我国森林生态系统土壤水分空间分异的62%(P<0.05);(2)我国北部与东部季风区森林区域土壤水分呈上升趋势,降水上升是主因,其中暖温带北京、南亚热带鼎湖山与鹤山森林土壤水分上升趋势显著,增幅分别为0.67%/a、1.72%/a与0.69%/a;西南地区森林生态系统土壤水分呈下降趋势,该趋势由降水下降与蒸散上升共同导致,其中中亚热带贡嘎山及哀牢山森林生态系统土壤水分下降趋势显著,降幅分别为-1.77%/a与-0.94%/a;土壤水分时间分异与降水蒸散差的相关性最高(R=0.59,P<0.01);(3)土壤水分呈下降趋势的森林生态系统中,春季土壤水分变化主导了年际变化,土壤水分上升的森林生态系统中,年际变化则是由秋、冬季主导。(4)与ERA-interim土壤水分再分析数据比较得出,两者在空间格局与变化趋势上均具有较高的一致性。CERN土壤水分观测数据反映了无人为干扰的自然条件下森林土壤-植被-气候之间的反馈作用,可为基于模型的土壤水分研究提供长时序的验证数据。  相似文献   

6.
黄土高原荒坡与林地土壤水分变化规律研究   总被引:12,自引:6,他引:12  
为探讨黄土高原有、无林地土壤水分全年变化规律之异同,在黄土高原半湿润区,采用中子水分测定仪定位测定方法,对无林沟坡(荒坡)与林地土壤水分储量变化进行了连续3年的定点测定,结果表明,在0-320cm的测定深度内,阴坡上、下部与阳坡下部荒坡土壤储水增量分别为-165.7mm、-115.2mm和-74.9mm;阴坡上部的油松林地,在0-320cm深度内,林地却在林木每年蒸腾消耗大量水分(达380mm以上  相似文献   

7.
Soil-surface CO2 efflux and its spatial and temporal variation were investigated in a southern Mediterranean, mixed pine-oak forest ecosystem on the northern slopes of the Sierra de Guadarrama in Spain from February 2006 to July 2006. Measurements of soil CO2 efflux, soil temperatures, and moisture were conducted in nine 1963-m2 sampling plots distributed in a gradient around the ecotone between Pinus sylvestris L. and Quercus pyrenaica Lam. forest stands. Total soil organic matter, Walkey-Black C, particulate organic matter, organic matter fraction below 53 microm, total soil nitrogen content, total soil organic carbon content, and pH were also measured under three representative mature oak, pine, and mixed pine-oak forest stands. Soil respiration showed a typical seasonal pattern with minimums in winter and summer, and maximums in spring, more pronounced in oak and oak-pine stands. Soil respiration values were highest in pine stands during winter and in oak stands during spring and summer. Soil respiration was highly correlated with soil temperatures in oak and pine-oak stands when soil moisture was above a drought threshold of 15%. Below this threshold value, soil moisture was a good predictor of soil respiration in pine stands. Greater soil organic matter, particulate organic matter, Walkey-Black C, total organic C, and total N content in pine compared to oak sites potentially contributed to the greater total soil CO2 efflux in these stands during the winter. Furthermore, opposing trends in the organic matter fraction below 53 microm and soil respiration between plots suggest that in oak stands, the C forms are less affected by possible changes in use. The effects of soil properties on soil respiration were masked by differences in soil temperature and moisture during the rest of the year. Understanding the spatial and temporal variation even within small geographic areas is essential to assess C budgets at ecosystem level accurately. Thus, this study bears important implications for the study of large-scale ecosystem dynamics, particularly in response to climatic change.  相似文献   

8.
东灵山油松林和辽东栎林下土壤资源和光资源的空间特征   总被引:8,自引:1,他引:7  
刘建  何维明  房志玲 《生态学报》2005,25(11):2954-2960
油松林和辽东栎林是中国暖温带具有代表性的森林植被林型。为揭示油松林和辽东栎林下土壤资源和光资源的空间特征,在东灵山相应植被下各设置一条100 m样线,利用HH 2高精度土壤水分仪(美国生产)沿样线每隔1 m测定土壤水分含量,并分析相应点土壤有机质含量;利用H em iV iew林冠分析系统每隔10 m测定森林的叶面积指数、林冠覆盖度、林冠均匀性、光资源状况;采用半方差方法分析土壤水分和有机质的空间异质性。(1)油松林与辽东栎林的叶面积指数、林冠覆盖度、辐射因子和林下光资源没有显著差异,但油松林林冠均匀性显著小于辽东栎林。(2)辽东栎林的间接辐射因子与林下总辐射呈显著正相关(R2=0.466,p=0.030),而油松林的间接辐射因子与总辐射无显著相关(R2=0.203,p=0.191)。(3)光资源的数量及其组成在油松林和辽东栎林下的变化非常相似,但光资源的组成与林冠特征的关系在两种森林间存在差异。(4)油松林下土壤水分和土壤有机质含量低于辽东栎林,但异质性恰好相反;油松林下这两种因子不具有显著的空间自相关性,而辽东栎林下具有显著的空间自相关性。(5)自然条件下,10 m尺度的林下辐射强弱与土壤水分之间并不存在显著负相关。  相似文献   

9.
武夷山植被带土壤微生物量沿海拔梯度的变化   总被引:11,自引:1,他引:11  
土壤微生物量是陆地生态系统碳循环的重要组成部分,在森林生态系统物质循环和能量转化中占有特别重要的地位.以武夷山常绿阔叶林(EBF)、针叶林(CF)、亚高山矮林(DF)和高山草甸(AM)为试验对象,研究了土壤微生物量沿海拔梯度的变化特征.结果表明:在0~10cm土壤层,随着海拔高度的增加,年平均土壤微生物量增大,AM的年平均土壤微生物量为4.07 g·kg-1,分别为DF、CF和EBF的2.06、3.21倍和3.91倍;AM的年平均土壤微生物量显著大于DF、CF和AM(p<0.01),DF的年平均土壤微生物量显著大于EBF、CF(p<0.05),EBF和CF的年平均土壤微生物量无显著性差异(p>0.05),10~25cm土壤层的年平均土壤微生物量的变化规律与上层基本一致;在0~10cm土壤层,不同海拔年平均土壤微生物量分别与土壤有机碳、全氮、全硫含量以及土壤湿度呈显著正相关(p<0.05),在10~25cm土壤层,不同海拔年平均土壤微生物量分别与土壤有机碳、全氮含量呈显著正相关(p<0.05).研究表明,武夷山亚热带森林年平均土壤微生物量随海拔高度升高而增加,土壤有机碳、全氮、全硫和土壤湿度可能是调控土壤微生物量沿海拔梯度变化的主要因子.  相似文献   

10.
Isodar theory can help to unveil the fitness consequences of habitat disturbance for wildlife through an evaluation of adaptive habitat selection using patterns of animal abundance in adjacent habitats. By incorporating measures of disturbance intensity or variations in resource availability into fitness-density functions, we can evaluate the functional form of isodars expected under different disturbance-fitness relationships. Using this framework, we investigated how a gradient of forest harvesting disturbance and differences in resource availability influenced habitat quality for snowshoe hares (Lepus americanus) and red-backed voles (Myodes gapperi) using pairs of logged and uncut boreal forest. Isodars for both species had positive intercepts, indicating reductions to maximum potential fitness in logged stands. Habitat selection by hares depended on both conspecific density and differences in canopy cover between harvested and uncut stands. Fitness-density curves for hares in logged stands were predicted to shift from diverging to converging with those in uncut forest across a gradient of high to low disturbance intensity. Selection for uncut forests thus became less pronounced with increasing population size at low levels of logging disturbance. Voles responded to differences in moss cover between habitats which reflected moisture availability. Lower moss cover in harvested stands either reduced maximum potential fitness or increased the relative rate of decline in fitness with density. Differences in vole densities between harvested and uncut stands were predicted, however, to diminish as populations increased. Our findings underscore the importance of accounting for density-dependent behaviors when evaluating how changing habitat conditions influence animal distribution.  相似文献   

11.
基于网格取样(20m×20m),采用经典统计学和地统计学相结合的方法,研究了干旱荒漠区煤矸石山表层(0~5 cm)土壤水分物理性质的空间异质性和分布格局.结果表明:研究区土壤容重、毛管孔隙度、毛管最大持水量、总孔隙度、饱和含水量表现为弱变异,土壤含水率表现为中等变异.除土壤容重的最佳拟合模型为高斯模型外,其余指标的最佳...  相似文献   

12.
子午岭植被恢复对土壤饱和导水率的影响   总被引:11,自引:0,他引:11  
梁向锋  赵世伟  张扬  华娟 《生态学报》2009,29(2):636-642
通过对子午岭林区不同植被的土壤性质进行实验室测定和野外调查,对饱和土壤水分运动的重要参数之一土壤饱和导水率(Ks)及其相关因子进行了多元分析和通径分析,揭示了植被恢复提高土壤水分传输性能的机理,主要结论如下:土壤有机质是子午岭林区九种植被下土壤饱和导水率提高的主要驱动因子.不同植被下的土壤饱和导水率均随深度的增加而迅速降低,尽管草地和先锋草地在5~10cm深度有一强透水层.土壤饱和导水率在剖面上的平均值,从辽东栎、早期森林、灌丛、先锋草地、弃耕地到草地依次降低.灌丛与草地、弃耕地的差异达到显著水平,辽东栎顶级群落的饱和导水率最高,植被的恢复明显提高了土壤饱和导水率.土壤容重、毛管孔隙度、>0.25mm团聚体含量及粘粒含量直接影响土壤饱和导水率.土壤有机质含量的提高能够改善容重、毛管孔隙度、团聚体含量等物理性质.  相似文献   

13.
It has been suggested that a feedback exists between the vegetation and soil whereby fertile (vs infertile) sites support species with shorter leaf life spans and higher quality litter which promotes rapid decomposition and higher soil nutrient availability. The objectives of this study were to (1) characterize and compare the C and N dynamics of dominant upland forest ecosystems in north central Wisconsin, (2) compare the nutrient use efficiency (NUE) of these forests, and (3) examine the relationship between NUE and site characteristics. Analyzing data from 24 stands spanning a moisture / nutrient gradient, we found that resource-poor stands transferred less C and N from the vegetation to the forest floor, and that N remained in the forest floor at least four times longer than in more resource-rich stands. Analyzing data by leaf habit, we found that less N was transferred to the forest floor annually via litterfall in conifer stands, and that N remained in the forest floor of these stands nearly three times longer than in hardwood stands. NUE did not differ among forests with different resource availabilities, but was greater for conifers than for hardwoods. Vitousek's (1982) index of nutrient use efficiency (INUE1)=leaf litterfall biomass / leaf litterfall N) was most closely correlated to litterfall specific leaf area and percent hardwood leaf area index, suggesting that differences in species composition may have been responsible for the differences in NUE among our stands. NUE2, defined as ANPP / leaf litterfall N, was not closely correlated to any of the site characteristics included in this analysis.  相似文献   

14.
子午岭林区白桦-辽东栎混交林光合生理生态特征研究   总被引:2,自引:0,他引:2  
秦娟  刘勇  上官周平 《西北植物学报》2006,26(11):2331-2337
对黄土高原子午岭次生林区白桦林、辽东栎林和白桦-辽东栎混交林3种林分的土壤物理特性和叶片光合特性进行了研究。结果表明:(1)白桦-辽东栎混交林地的土壤水分明显改善,其土壤容重最小、土壤孔隙度最大,且均优于纯林,即混交林地有深层次的土壤水分可供利用,并改善了土壤的物理结构;(2)辽东栎林的光合速率和气孔导度最大,其次为白桦-辽东栎混交林,水分利用率(WUE)为混交林白桦>混交林辽东栎>辽东栎林>白桦林;(3)混交林中白桦、辽东栎的Fv/Fm和Fv/Fo值均较大,与纯林差异不显著;白桦林和辽东栎林的qP和NPQ值均大于混交林。  相似文献   

15.
Water uptake profile response of corn to soil moisture depletion   总被引:6,自引:1,他引:5  
The effects of soil moisture distribution on water uptake of drip‐irrigated corn were investigated by simultaneously monitoring the diurnal evolution of sap flow rate in stems, of leaf water potential, and of soil moisture, during intervals between successive irrigations. The results invalidate the steady‐state resistive flow model for the continuum. High hydraulic capacitance of wet soil and low hydraulic conductivity of dry soil surrounding the roots damped significantly diurnal fluctuations of water flow from bulk soil to root surface. By contrast, sap flow responded directly to the large diurnal variation of leaf water potential. In wet soil, the relation between the diurnal courses of uptake rates and leaf water potential was linear. Water potential at the root surface remained nearly constant and uniformly distributed. The slope of the lines allowed calculating the resistance of the hydraulic path in the plant. Resistances increased in inverse relation with root length density. Soil desiccation induced a diurnal variation of water potential at the root surface, the minimum occurring in the late afternoon. The increase of root surface water potential with depth was directly linked to the soil desiccation profile. The development of a water potential gradient at the root surface implies the presence of a significant axial resistance in the root hydraulic path that explains why the desiccation of the soil upper layer induces an absolute increase of water uptake rates from the deeper wet layers.  相似文献   

16.
Two of the main hypotheses to explain the distribution and special characteristics of tropical heath forest are nutrient and water limitation. A study was undertaken to investigate both factors on two sites under tropical heath forest (Badas Forest Reserve) and mixed‐dipterocarp forest (Andulau Forest Reserve) in Brunei. Soil water potentials were monitored at depths of 20, 50, and 90 cm over wet and dry periods for five months at each site. The results showed the mixed‐dipterocarp forest site to be drier at 50 cm depth compared to the tropical heath forest site. There was no significant difference in water potentials between sites at 20 or 90 cm. Nutrient concentrations in the soil solution were monitored at the same depths over a seven‐month period at the same sites. A 12‐month litterfall study was also undertaken to monitor nutrient returns from the canopy at each site. The results of both studies suggest that the tropical heath forest site is poorer in nitrogen, but richer in calcium, than the mixed‐dipterocarp forest site. The results for phosphorus are less clear, but do not suggest that its limitation is a significant factor at the tropical heath forest site compared to the mixed‐dipterocarp forest site. Phosphorus and magnesium concentrations in the soil solution showed a strong positive correlation with sliding 30‐day rainfall totals at both sites.  相似文献   

17.
杨鑫  曹靖  董茂星  马晓军 《应用生态学报》2008,19(10):2109-2116
以甘肃小陇山林区8~30年林龄日本落叶松林(外来树种)、油松林(乡土树种)及次生林为研究对象,研究了不同树种森林的土壤质量和细菌多样性变化.结果表明: 不同树种森林土壤pH无明显变化;林龄越长,土壤含水量越高.土壤总氮与有机质含量以次生林最高,其次为日本落叶松,油松最低.不同林龄森林土壤总氮与有机质含量无明显变化,表明树种是影响土壤质量的主要因素.与乡土树种油松相比,外来树种日本落叶松显著提高了土壤全氮及土壤有机质含量.变性梯度凝胶电泳(DGGE)图谱显示,次生林土壤细菌多样性最高,而外来树种日本落叶松土壤细菌多样性最低.对DGGE图谱的聚类分析发现,小陇山不同森林土壤细菌类群分属变形杆菌、噬纤维黄杆菌和高G+C含量革兰氏阳性细菌类,其中分属变形杆菌为主要类群.进一步分析发现,日本落叶松的细菌群落组成具有更高的相似度,说明日本落叶松正在使该地区土壤细菌多样性发生变化.  相似文献   

18.
山西太岳山小流域土壤水分空间异质性及其影响因子   总被引:5,自引:0,他引:5  
以山西太岳山华北落叶松林地为主的小流域作为研究对象,采用地统计学方法结合地理信息系统(GIS)技术手段,研究了接石沟小流域土壤水分(0—60cm)的空间变异特征,以及植被分布和地形因子对其影响规律。结果表明:在时间稳定性的前提下,土壤水分含量和变异系数随土层加深逐渐降低。三层土壤水分半方差函数的最优拟合模型为球状模型,变程范围在1.1—1.4 km,均具有强烈的空间自相关性,其中0—20 cm和20—40 cm层土壤水分的空间异质性程度高于40—60 cm土层,以中间层的结构因素占总变异比例最大。自然结构因素(地形、母质、植被和土壤等)对不同土层土壤水分的总空间变异性起主导作用(81.4%—91.3%),而随机因素(取样误差、人为干扰等)的影响相对较小(8.7%—18.6%)。沿着集水线由西-东方向,从边缘的土壤水分高值斑块区逐渐过渡到明显的低值斑块区,梯度变化明显。研究发现,在植被覆盖异质性小的山地,土壤水分的空间异质性主要由地形因素引起,具体表现为其与坡向指数(TRASP)、坡度、海拔和土壤有机碳、全氮呈极显著相关关系(P0.01),而与植被指数(NDVI)呈弱的负相关关系。叠加分析显示,在阴坡、坡度较缓(15°)及高海拔叠合的区域土壤水分含量较高。研究结果可为山地人工林构建和植被恢复中土壤水资源的利用以及水分管理策略的制定提供理论依据。  相似文献   

19.
Moisture availability has the potential to affect tropical forest productivity at scales ranging from leaf to ecosystem. We compared data for leaf photosynthetic, chemical and structural traits of canopy trees, litterfall production and seasonal availability of soil water at four sites across a precipitation gradient (1,800–3,500 mm year–1) in lowland Panamanian forest to determine how productivity at leaf and ecosystem scales may be related. We found stronger seasonality in soil water potential at drier sites. Values were close to zero at all sites during the wet season and varied between a minimum of –2.5 MPa and –0.3 MPa at the driest and wettest sites, respectively, during the dry season. Leaf photosynthesis and nitrogen concentration decreased with increasing precipitation, whereas leaf thickness increased with increasing precipitation. Leaf toughness and fiber/N ratios increased with increasing precipitation indicating reduced nutritional content and palatability with precipitation. Seasonality of litter production and quality decreased with increasing precipitation, but the amount of litterfall produced was not substantially different among sites. It appears that in Neotropical forest, moisture availability is associated with leaf photosynthetic and defensive traits that influence litterfall timing and quality. Therefore, variation in leaf physiological traits has the potential to influence decomposition and nutrient cycling through effects on litter quality.  相似文献   

20.
韩路  王海珍 《生态学报》2024,44(2):832-843
探讨荒漠河岸林土壤水分、物种多样性的空间变异性及其相互关系,可为干旱区天然林保护、可持续经营和生态恢复提供科学依据。以塔里木荒漠河岸林为研究对象,基于野外样带调查和采样测定,系统分析了地下水埋深(GWD)梯度下林地土壤水分与物种多样性的空间变异及其权衡关系。结果表明:随GWD增加和土壤水分减少,荒漠河岸林群落物种数减少、结构简化、群落发生退化,退化顺序为浅根系的中生草本植物和灌木,最后留存的是抗旱性较强的乔灌木或灌木;同时土壤水分和物种丰富度、物种多样性指数均呈显著的线性递减趋势,而物种均匀度指数降幅较小。GWD与土壤水分、物种多样性之间均呈极显著的相关(P<0.01),土壤水分与物种多样性的相对收益随GWD增加而逐渐降低,表明GWD是控制荒漠河岸林土壤水分和物种多样性空间变异的关键因素。荒漠河岸林土壤水分与物种多样性权衡关系的转折点为GWD 4.5m左右,转折点以下(GWD<4.5m)二者沿GWD以相同速率变化,呈协同关系;转折点以上(GWD>4.5m)土壤水分与物种多样性的权衡明显增大,土壤水分相对收益剧降,即维持当前相应的物种多样性以消耗土壤水分为代价,系统通过反馈调节使物种多样性降低。综上表明,维持塔里木荒漠河岸林物种多样性和生态系统功能的合理GWD在4.5m左右,这为塔里木河流域荒漠河岸林保育与生态输水工程实施提供科学依据。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号