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1.
王道杰  崔鹏  朱波  韦方强 《土壤通报》2004,35(6):683-687
小江流域泥石流滩地水源充足、热量丰富,气候生产潜力(47641kghm-2)较高。本文应用加权指数和法确定了不同类型泥石流滩地(荒滩地、改良滩地和非改良滩地)土壤有效系数f(s)分别为0.405、0.684和0.594;根据生产力阶乘公式计算其气候—土壤生产潜力分别为19295kghm-2、32586kghm-2和28299kghm-2。通过实地调查验证,本文对泥石流滩地生产潜力的估算与现实生产力水平基本吻合,证明本文提出的泥石流滩地土壤有效系数切实可行。  相似文献   
2.
This study examines watershed patterns of riparian vegetation, shade, and stream temperature eight years after extreme storm events triggered numerous debris torrents throughout the Pacific Northwest. We examined twelve impacted streams in two western Oregon watersheds: the Calapooia River in the western Cascades and the Williams River in the Coast Range. Red alder (Alnus rubra) and willow (Salix spp.) were the dominant species on debris torrented areas in both watersheds. Post-disturbance vegetation recovery was significant in both watersheds, impacting shade and stream temperatures. However, red alder density, basal area, and height were significantly greater along streams in the Williams River watershed than along streams in the Calapooia River watershed. Willow density, basal area and height were similar between the watersheds. Stream shading levels mirrored red alder growth, with greater average shading in the Williams River watershed. The greater shade translated into lower summer maximum stream temperatures and maximum diurnal stream temperature fluctuations in the Williams River as compared to the Calapooia River watershed. Minimum stream temperatures were not different between the two watersheds. The rapid re-growth of red alder along the Williams River watershed ultimately lead to a rapid decline in maximum summer stream temperatures for that watershed compared to the Calapooia River watershed. The location where the disturbance occurred had an important role in determining the rate and pathway of stream recovery.  相似文献   
3.
刘冰  宋玉玲  邓祥征 《农业科学与技术》2012,(5):1081-1085,1132
[目的]对舟曲泥石流造成的直接和间接经济损失进行评估。[方法]在 2010 年 8 月 7 日舟曲发特大泥石流发生的后第一时间收集了相关数据,建立评估模型,采用比例系数法估计潜在的经济损失。[结果]评估结果表明,此次灾害共造成经济损失 16.57 亿元人民币,其中间接经济损失高达2.42 亿,直接经济损失 14.15 亿。[结论]至目前为止,比例系数法仍是一种快速有效的评估间接经济损失的方法。  相似文献   
4.
Dendrogeomorphological analyses of trees affected by debris flows have regularly been used to date past events. However, this method has always been limited to forested cones where trees registered the impact of previous events. The minimum age dating of trees growing in the debris deposits can, in contrast, provide information on the latest possible moment of past activity. In this paper, we report on results obtained from a combination of these two approaches on a forested cone in the Valais Alps (Switzerland). A detailed geomorphic map in a scale of 1:1000 served as a basis for the sampling strategy. Disturbed Larix decidua Mill. and Picea abies (L.) Karst. trees growing in the deposits allowed reconstruction of 49 events between AD 1782 and 2005 as well as the determination of the spatial extent of events. In the debris-flow channels where survivor trees are missing, we selected the oldest post-event trees and assessed their age by counting their growth rings. Missing rings due to lack of center as well as to sampling height were added so as to determine real tree age. The combination of the dendrogeomorphological event reconstruction with the assessment of germination dates of successor trees allowed realistic approximation of the minimum time elapsed since the last debris-flow activity in 23 of the 29 channels present on the current-day cone surface. In general, channels in the northern part of the cone and those close to the currently active channel generally show signs of (sub-) recent activity with one last overbank sedimentation event in the 1980s, whereas signs of debris-flow activity are absent from the channels in the outermost part since the late 19th century. As a consequence of the deeply incised channel and the stabilization measures undertaken along the banks, signs of debris flows are missing in the tree-ring record for the past two decades.  相似文献   
5.
泥石流对岩性的敏感性研究现状及展望   总被引:1,自引:0,他引:1  
论述了泥石流对岩性的敏感性研究现状,分析了当前该研究中存在的不足,并指出了今后泥石流对岩性敏感性研究的主要发展方向。  相似文献   
6.
对润滑油磨粒进行检测,国内外已形成诸多技术,但都存在一定缺陷,对此提出了针对柴油发动机润滑油磨粒基于图像识别的在线监测技术,设计了实现磨粒识别监测的硬件系统,阐述了其实现的关键技术。该技术能实现实时在线和离线的检测。  相似文献   
7.

Spatiotemporal patterns of standing and fallen dead trees were examined in two protected Scots pine ( Pinus sylvestris L.)-Norway spruce ( Picea abies (L.) Karst.) forests in eastern Finland (Pahkavaara and Pönttövaara). In Pahkavaara the volume of standing dead trees was 10 m 3 ha -1 and the volume of fallen logs was 66 m 3 ha -1 , and in Pönttövaara the values were 48 m 3 ha -1 and 107 m 3 ha -1 , respectively. The areas differed with respect to the tree species composition, whereas the proportion of different decay stages was similar. Decay stage and dendrochronological analyses revealed the continuity of dead wood formation. The spatial pattern of standing dead trees was usually towards clustered. The volumes of fallen logs showed a spatial autocorrelation up to distances of 10-20 m. The results also suggest that the current amount and diversity of dead wood is rather high, but that forest succession is likely to lead to a less diverse state in the future.  相似文献   
8.
以建设白龙江流域泥石流灾害空间数据库为目标,在对现有的数据整理分析的基础上,通过概念设计、逻辑结构设计和数据库建设3个步骤说明了泥石流灾害空间数据库的设计流程,并采用了ArcGIS Diagrammer工具建立UML模型完成泥石流数据库的设计.  相似文献   
9.
通过分析云南省东川区的森林资源现状及降雨量等外部环境因子和泥石流灾害的关系得出以下结论:东川区森林处于成长期,不稳定,结构不合理,林业生态环境非常恶劣;东川区泥石流灾害次数与降水量之间有显著相关关系,降水量多的时间段,泥石流灾害次数也相对较多,反之则较少。  相似文献   
10.
龙洞沟泥石流滩地剖面结构和土壤物理结构较差 ,砂石化现象严重 ;土壤微团聚体数量较少 ,粒级间比例不合理 ;土壤养分除全钾极丰富外 ,其它大部分养分都处于缺乏或极缺状态。通过开发利用 ,其表土层结构特性和养分状况得到显著改善 :砾石含量由 63 .0 3~ 70 .78%减少到 3 9.66~ 57.62 % ,粉粒和粘粒含量由 2 6.75~ 3 1.89%增加到 3 0 .54~41.93 % ;有机质由 7.1~ 10 .8gkg- 1提高到 15.8~ 2 6.9gkg- 1;全氮由 1.2 0~ 1.40gkg- 1提高到 1.50~ 1.93gkg- 1;全磷由0 .46~ 0 .57gkg- 1提高到 0 .48~ 0 .79gkg- 1;有效氮由 47.2 2~ 56.67mgkg- 1提高到 79.3 9~ 119.46mgkg- 1;有效磷由 2 .2 1~ 4.69mgkg- 1提高到 5.58mgkg- 1;有效钾由 2 9.84~ 40 .3 6mgkg- 1提高到 51.89~ 89.3 6mgkg- 1。不同利用模式的改良作用不同 ,依次为 :菜园地 >苹果 +蔬菜地 >苹果园地 >苹果 +花椒地 >花椒园地 >荒滩地  相似文献   
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