共查询到19条相似文献，搜索用时 828 毫秒
1.
柠条具有耐寒、耐旱、适应性强等特点,是干旱地区水土保持、防风固沙造林中的优良树种。本文通过对湟中县徐家寨柠条平茬更新的生物量调查,说明了平茬技术对改良柠条林、提高其生态效益和经济效益的重要性。 相似文献
2.
李日胜 《内蒙古科技与经济》2001,(3):98-98
柠条也叫锦鸡儿 ,系豆科锦鸡儿属植物。具有适应性强、抗严寒、酷暑、耐瘠薄、耐旱力强等特点 ,是乌盟地区水土保持和固沙造林的主要树种。柠条虽然有这么多优良特性 ,但是 :柠条从播种、发芽、出土后幼苗生长期里若连续干旱无降雨达1 0天以上 ,就会造成柠条的“闪芽”和“吊死”。近年来 ,乌盟地区采用雨季直播柠条造林 ,成效不太理想 ,成活率低。究其原因 ,主要是由于上述原因和蝗虫的危害造成的。今年丰镇市林业科技人员 ,在实施阴山北麓沙源治理工程中 ,选择风蚀沙化较严重的隆盛庄镇沙卜项目区 ,采用地膜覆盖技术 ,直播柠条造林 ,收到… 相似文献
3.
奇志 《内蒙古科技与经济》2004,(23):33-34
2002年和2003年达拉特旗林业局在本旗硬梁覆沙区进行了两次飞播大柠条、杨柴、籽蒿、沙打旺试验,采取有效措施,解决了大柠条成苗率低的问题,并取得成功,本文主要介绍了这两次试验情况。大柠条又称锦鸡儿、白柠条,属豆科锦鸡儿属植物,为荒漠沙生、旱生灌木,生长于沙丘、沙地、硬梁覆沙地及硬梁地上,其植株较高(一般高1.5～3m,有的甚至高5m),根系发达(6年生大柠条主根长达3.9m,侧根长4.5m,根冠幅5.9×5.9m,密集根层40～160cm),枝叶茂密,冠幅较大(6年生大柠条冠幅平均直径3.8m),固其防风固沙作用很大,是营造防风固沙林的优良树种。另外,大柠条… 相似文献
4.
柠条锦鸣儿是优良的沙生植物．也是鄂尔多斯沙区的主要建群植物种。为了挖掘其固定流沙、适应干旱、需瘠薄的物植品能．笔者根据我年的造林固沙实践经验，调查研究了宁条鸡儿地上枝条与花果的生物量投资结构及时空分布．为柠条鸡儿的数字造林提供基础数据。 相似文献
5.
7.
为了探讨不同林分涵养水源功能,为该地区林业发展提供技术依据,以清水河县公益林林区内5种林分为研究对象,调查分析了土壤层及涵养水源等生态功能。研究表明:土壤容重从大到小的顺序均为:无林地柠条林杨树柠条林油松林杨树油松混交林杨树林。土壤总孔隙度为:杨树林杨树油松混交林油松林杨树柠条混交林柠条林无林地。不同林分林型涵养水源能力差异较大,杨树油松混交林涵养水源能力最好,为284.35t/hm~2;柠条林为172.98t/hm~2;无林地最差,为128.35t/hm~2。因此,在清水河县地区适度发展阔叶林和针阔混交林,具有较高的涵养水源效益。 相似文献
8.
大坝小流域是 1 997年开始规划的 ,1 998年付诸实施。针对该流域水土流失的主要成因 ,在治理过程中植物措施主要采取了人工种植柠条。经过几年的综合治理 ,流域内水土流失得到了明显的控制 ,沙漠化土地得到了遏制和有效的利用 ,其中柠条林充分发挥了其防风固沙和促进当地畜牧业 相似文献
9.
赵欣宇 《内蒙古科技与经济》2023,(3):94-97
为了研究武川县不同林分类型的土壤理化性质，文章选取内蒙古武川县为研究区域，利用ArcGIS等软件提取坡度、坡向进行叠加处理并从多个方面进行分析，以期为武川县后续树种的科学种植以及土壤养分的研究提供参考依据。研究表明：(1)柠条(Caragana Korshinskii)与沙棘(Hippophae rhamnoides)进行混交得到的混交林则可显著提升土壤非毛管孔隙度大小；两种混交林样地的土壤容重都显著降低，以便于林地的生长种植。(2)不同林分类型的土壤有机质、碱解氮和速效钾的含量均比速效磷含量高。两种混交林的有机质含量比单一林分类型的有机质含量均要高，其中，沙棘与柠条混交林的碱解氮含量比其他样地内的林分类型含碱解氮要高出很多。 相似文献
10.
为探究砒砂岩区不同柠条配置模式对坡面水蚀过程的影响,本文通过径流小区野外放水冲刷试验,从水蚀特征和能量角度,分析多冲刷强度下坡面径流的时空动态特征,对于砒砂岩区人工植被的生态恢复配置具有重要的现实指导意义。结果表明：(1)各冲刷强度下,不同柠条配置模式初始产流产沙时间、平均产流产沙速率都呈GL(无灌木)>SU(坡上)>SM(坡中)>SL(坡下);(2)各柠条配置模式,土壤剥蚀率与单位水流功率、弗劳德数呈显著正相关,阻力系数呈显著负相关(P<0.01);(3)各冲刷强度径流能耗与土壤剥蚀率均具有显著的相关性(P<0.05),且配置位置越靠下,对径流侵蚀能量的削弱作用越明显。 相似文献
11.
张明理 《中国科学院研究生院学报》1997,35(2):136-147
锦鸡儿属Caragana是一个典型的温带亚洲分布属。本属在青藏高原和喜马拉雅约有24种1变种，约占整个属的1／3。这些种类几乎全部处于演化高级阶段，且既有叶轴宿存类群，也有假掌状叶类群。反映出种的分化很活跃，在横断山地区形成本属的分布中心、分化中心。本区内绝大多数种类是特有分布。替代现象主要受气候、植被变化作用，沿横断山和喜马拉雅分布的长齿系Ser. Bracteolatae Kom．是一个典型的替代分布类群。锦鸡儿属植物生态适应性很强，可在其生长的灌丛中形成优势种。 寒化和旱化现象十分突出，它们有一系列森林种、草原种和荒漠种及相关的形态变异。用锦鸡儿属植物进行青藏高原和喜马拉雅区域内的分布区关系分析及最小生成树MST和特有性简约性分析(PAE)，表明横断山地区特别是其北部是本属植物的一个地理结点。以此沿横断山向北部唐古特和西部藏东南适应性辐射。横断山和西喜马拉雅联系微弱，看不出植物长距离扩散的踪迹，大多是由于生态因子限制而产生的隔离。虽然本区不可能是锦鸡儿属的起源地，然而，通过本区与邻近地区的地理联系，可推测它们在我国适应性辐射方向是从东北向西南。结合豆科蝶形花亚科其它属化石记录及其分布区局限在温带亚洲等现象，认为锦鸡儿植物是一组特化、晚近衍生的类群，起源于北方东西伯利亚晚第三纪中新世后期至上新世。 相似文献
12.
倪志诚 《中国科学院研究生院学报》1991,29(1):84-85
Caragana sajaensis Ni (Leguminosae)is described from Xizang, China, asnew. 相似文献
13.
Xizang (Tibet) is rich in Leguminosae flora, comprising 41 genera and 254 species
so far known, exclusive of the commonly cultivated taxa (including 11 genera and 16
species). There are 4 endemic genera (with 8 species), 10 temperate genera (with 175
species) and 19 tropical genera (with 46 species) as well as the representatives of those
genera whose distribution centers are in East Asia-North America, Mediterranean
and Central Asia.
1. There are altogether 4 endemic genera of Leguminosae in this region. Accord-
ing to their morphological characters, systematic position and geographical distribution,
it would appear that Salweenia and Piptanthus are Tertiary paleo-endemics, while
Straceya and Cochlianths are neo-endemics. Salweenia and Piptanthus may be some
of more primitive members in the subfamily Papilionasae and their allies are largely
distributed in the southern Hemisphere. The other two genera might have been derived
from the northern temperate genus Hedysarum and the East Asian-North American
genus Apios respectively, because of their morphological resemblance. They probably
came into existanc during the uplifting of the Himalayas.
2. An analysis of temperate genera
There are twelve temperate genera of Leguminosae in the region, of which the
more important elements in composition of flora, is Astragalus, Oxytropis and Cara-
gana.
Astragalus is a cosmopolitan genus comprising 2000 species, with its center
distribution in Central Asia. 250 species, are from China so far known, in alpine zone of
Southwest and Northwest, with 70 species extending farther to the Himalayas and
Xizang Plateau.
Among them, there are 7 species (10%) common to Central Asia, 12 species (15.7%)
to Southwest China and 40 species (60%) are endemic, it indicates that the differentia-
tion of the species of the genus in the region is very active, especially in the subgenus
Pogonophace with beards in stigma. 27 species amounting to 78.5% of the total species of
the subgenus, are distributed in this region. The species in the region mainly occur in
alpine zone between altitude of 3500—300 m. above sea-level. They have developed into
a member of representative of arid and cold alpine regions.
The endemic species of Astragalus in Xizang might be formed by specialization of
the alien and native elements. It will be proved by a series of horizontal and vertical vicarism of endemic species. For example, Astragalus bomiensis and A. englerianus are
horizontal and vertical vicarism species, the former being distributed in southeast part
of Xizang and the latter in Yunnan; also A. arnoldii and A. chomutovii, the former
being an endemic on Xizang Plateau and latter in Central Asia.
The genus Oxytropis comprises 300 species which are mainly distributed in the
north temperate zone. About 100 species are from China so far known, with 40 species
extending to Himalayas and Xizang Plateau. The distribution, formation and differ-
entiation of the genus in this region are resembled to Astragalus. These two genera are
usually growing together, composing the main accompanying elements of alpine mea-
dow and steppe.
Caragana is an endemic genus in Eurasian temperate zone and one of constructive
elements of alpine bush-wood. About 100 species are from China, with 16 species in Xi-
zang. According to the elements of composition, 4 species are common to Inner Mon-
golia and Kausu, 4 species to Southwest of China, the others are endemic. This not only
indicates that the species of Caragana in Xizang is closely related to those species of
above mentioned regions, but the differentiation of the genus in the region is obviously
effected by the uplifting of Himalayas, thus leading to the formations of endemic species
reaching up to 50%.
3. An Analysis of Tropical Genera
There are 19 tropical genera in the region. They concentrate in southeast of Xizang
and southern flank of the Himalayas. All of them but Indigofera and Desmodium are
represented by a few species, especially the endemic species. Thus, it can be seen that
they are less differentiated than the temperate genera.
However, the genus Desmodium which extends from tropical southeast and northeast
Asia to Mexio is more active in differentiation than the other genera. According to Oha-
Shi,s system about the genus in 1973, the species of Desmodium distributed in Sino-Hima-
laya region mostly belong to the subgenus Dollinera and subgenus Podocarpium. The
subgenus Dollinera concentrates in both Sino-Himalaya region and Indo-China with 14
species, of which 7 species are endemic in Sino-Himalaya. They are closely related to
species of Indo-China, southern Yunnan and Assam and shows tha tthey have close con-
nections in origin and that the former might be derived from the latter.
Another subgenus extending from subtropical to temperate zone is Podocarpium.
Five out of the total eight species belonging to the subgenus are distributed in Sino-
Himalaya and three of them are endemic.
An investigation on interspecific evolutionary relationship and geographic distribu-
tion of the subgenus shows that the primary center of differentiation of Podocarpium
is in the Sino-Himalaya region.
Finally, our survey shows that owing to the uplifting of the Himalayas which has
brought about complicated geographic and climatic situations, the favorable conditions
have been provided not only for the formation of the species but also for the genus in cer-tain degree. 相似文献
14.
此次新冠肺炎疫情传播速度快、影响范围广、防控难度大,在没有特异性治疗药物和疫苗的情况下,我国通过最全面彻底的、以"非医疗干预"手段为主的防控举措,全社会动员,全民参与,科学防治、精准防治,有效遏制了本土疫情,取得了阶段性重要成效。在此次疫情防控中,我国各级公共卫生与疾病预防控制(以下简称"疾控")体系起到了重要作用,但也暴露出了诸多短板和不足。文章梳理了现阶段我国疾控体系、公共卫生法律法规建设、卫生应急管理政策保障3个方面存在的突出问题,提出了新时代疾控体系的职能任务发展、关键科研技术建设和专业人才资源储备3个方面的具体建议。 相似文献
15.
概括和总结了现代机械科学技术发展的特点和趋势,阐述了机械科学技术作为一门重要的基础性工程科学技术,对经济发展和社会进步所起的积极推动作用.在此基础上对我国目前的机械科学技术和机械工业的发展现状作了简要分析,指出我国机械科学技术研究发展工作中存在的问题和不足,并就发展我国机械科学技术和机械工业的对策进行了讨论. 相似文献
16.
高校知识产权工作已成为我国高校科技工作的重要组成部分。论文分析高校知识产权管理工作中存在的问题并提出相应的对策;建议构建校企平台,加强高校产学研合作,建立技术转移机构,促进知识产权实施与应用。 相似文献
17.
我国创新政策体系日益完善,然而政策实施后缺少专业部门跟踪进程及成效,产生高投入低产出现象。因而建立一个配套的创新政策绩效评估体系,形成"成果挂钩的管理和预算系统"十分必要,文章研究了欧美国家在创新政策绩效中使用的评估模型和方法,对我国创新型国家建设具有重要的现实意义。 相似文献
18.
现在我国高校,特别是理工科为重点的高校在开展思想政治教育理论课程中存在着严重的问题,并且呈现出学生对学习思想政治教育的认知能力自觉性差、教师对学习思想政治教育的教学力度着重性弱、学校对学习思想政治教育的教育方式层次性低的特点,针对这些当前的现状和特点,提出了相应解决的改革途径。 相似文献
19.
新加坡与马来西亚在地理位置、历史文化传统上有很多相似之处,这对两国的思想政治教育也产生了一定的影响。两国的思想政治教育既有相同之处也有不同之处。本文通过对新马两国思想政治教育的内容和方法进行异同分析,进而得到两国思想政治教育比较的启示。 相似文献