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 109 毫秒
1.
苗圃转让     
今年顺义区苗圃绿化、美化苗木达1120多种、1.12亿株。其中油松、白皮松、华山松、雪松、桧柏、侧柏等常绿树13157亩,1650万株,占育苗总面积的23%;连翘、碧桃、榆叶梅、紫叶李、紫蔽、紫荆、月季、玫瑰、黄刺梅、黄杨、女贞等花灌木5468亩,1455万株,占育苗总面积的10%;白腊、元宝枫、栾树、国槐、银杏、合欢、龙爪槐、杜仲、千头椿、金丝柳、各种品种杨等落叶乔木37375亩,8095万株,占育苗总面积的67%。  相似文献   

2.
大丽花块根繁育和栽培技术   总被引:2,自引:0,他引:2  
大丽花(Dahlia pinnata Cav)菊科,大丽花属,多年生草本,原产墨西哥,又名大丽菊、大理花、天竺牡丹、西番莲、地瓜花,具有植株粗壮、花期长、花朵硕大,品种繁多、花色鲜艳、适应性强等特点。是美化公园,布置庭院、花坛、花境以及切花陈设的较好花卉材料。大丽花为世界名花之一,目前世界约有3万多个品种,我国有500余品种。  相似文献   

3.
木棉(Gossampinus malabarica)又名攀枝花、红棉、英雄树、烽火树,属木棉科木棉属落叶高大乔木.木棉广泛分布在我国四川、云南、贵州、广西、广东,生长在江河沿岸、山地阳坡及村边道路旁,喜光、耐高温,对土壤要求不苛刻.在四川攀枝花地区木棉树于1月-2月份开花,先花后叶,花色艳丽,有红色、金黄、淡黄色等颜色,树形高大伟岸,是优良的园林绿化树种.木棉树现是攀枝花市市花和广州市市树,在园林绿化中常作行道树、庭荫树、景园树、盆景树等.木棉经嫁接后2 a-3 a开花,嫁接苗可作盆景矮化栽培,观赏价值高.本文介绍了木棉的嫁接育苗技术.  相似文献   

4.
To improve multi-environmental trial(MET)analysis,a compound method—which combines factor analytic(FA)model with additive main effect and multiplicative interaction(AMMI)and genotype main effect plus genotype-by-environment interaction(GGE)biplot—was conducted in this study.The diameter at breast height of 36 open-pollinated(OP)families of Pinus taeda at six sites in South China was used as a raw dataset.The best linear unbiased prediction(BLUP)data of all individual trees in each site was obtained by fitting the spatial effects with the FA method from raw data.The raw data and BLUP data were analyzed and compared by using the AMMI and GGE biplot.BLUP results showed that the six sites were heterogeneous and spatial variation could be effectively fitted by spatial analysis with the FA method.AMMI analysis identified that two datasets had highly significant effects on the site,family,and their interactions,while BLUP data had a smaller residual error,but higher variation explaining ability and more credible stability than raw data.GGE biplot results revealed that raw data and BLUP data had different results in mega-environment delineation,test-environment evaluation,and genotype evaluation.In addition,BLUP data results were more reasonable due to the stronger analytical ability of the first two principal components.Our study suggests that the compound method combing the FA method with the AMMI and GGE biplot could improve the analysis result of MET data in Pinus teada as it was more reliable than direct AMMI and GGE biplot analysis on raw data.  相似文献   

5.
Natural spruce-fir mixed stand is one of the main forest types in the world,and also has huge ecological,economic and social benefits.According to the structural characteristics and succession laws of natural spruce-fir forest,it is urgent and significant to develop scientific management measures for natural spruce-fir mixed stand in line with local conditions.The article outlined the characteristics of the distribution and structure, regeneration and succession laws of natural spruce-fir forest,and analyzed the current situation and existing problems of natural spruce-fir forest management.The following recommendations were eventually made:1) In no cutting area,all logging activities should be banned.In a restricted cutting area,the cutting intensity should be generally controlled within 15%of the stock volume before cutting.On the commodity forest management area, the appropriate cutting intensity should be determined according to the volume per hectare,determine and classification management should be implemented in accordance with the characteristics of forest,to ensure the scientific selective cutting.2) Closure for afforestation,planting and repair planting should be adopted on vegetation-intensive land,sparse shrubs covered land and harvesting slash,in order to accelerate natural regeneration.3) The in situ conservation should be conducted in nature reserves and scientific experiment stations of rare and endangered species,such as Abies chensiensis,Picea neoveitchii,Abies vuanbaoshanensis,to reduce human destruction.4) It is supposed to collect seeds in time,establish nursery,actively establish forest, expand artificial population and promote natural regeneration.  相似文献   

6.
蚊子、苍蝇、螳螂、臭虫、蜘蛛、蚂蚁之类害虫,在家庭、工厂、办公室、医院、学校、酒店等地,随处可见,无处不入.这些昆虫不但给人们的生活带来很多烦恼,更重要的是,他们导致疾病传播,从而严重危害人们的身体健康.所以,根除害虫,改变居住环境,早已成为人们关注的问题.  相似文献   

7.
肥胖是一种常见的慢性疾病,它是由于生理化机能的改变而引起的体内脂肪沉积量过多,造成体重增加,导致机体发生一系列病理、生理变化的病症.肥胖症是一种全身性代谢疾病,除引起身体外形的改变外,过多的脂肪可带来物理性的负荷,还是各种疾病的"培养箱".肥胖人群平均寿命明显低于正常体重的人群,同时肥胖症还是心血管疾病、糖尿病、脂肪肝、肿瘤的温床,它是一种营养代谢性疾病.减肥首先必须从能量的摄入入手,减少热能的吸收.  相似文献   

8.
当前现代化的航天、航空、汽车、机械、电子、民用建筑、化工等行业迫切要求具备很高的力学性能及耐热、耐磨、耐化学性能的材料.因此高分子材料发展的一个重要方向就是通过对现有聚合物进行物理和化学改性,使其进一步高性能化、结构化、工程化.北京化工大学研制的聚氯乙烯合金是通过挤出机的力学、化学作用及接枝、复合技术使聚氯乙烯塑料工程化,成为物理性能可与ABS相比拟的新材料.聚氯乙烯合金具有高流动性、高韧性,完全可以代替ABS注塑计算机、电视机、冰箱、照相机、仪表等外壳.聚氯乙烯合金还具有良好的耐寒性,可制作各种规格的异型材,包括门窗、上水管道等.产品市场前景好,具有很强的竞争力,有很好的经济效益和社会效益.  相似文献   

9.
According to the unification principle of system structure and system function of the Water Resource Conservation Forests,seven factors were selected from stand spatial structure,trees structure and healthy of woods,the multifunction management optimization model target was confirmed by using nonlinearity multi-objective programming approach, and the target function-stand spatial structure homogeneity index was defined to establish spatial optimization models with restraining conditions set up in diversity of stand structure and spatial structure.The spatial structure of available typical stand in the wet land area in southern Donting Lake was optimized by means of selective cutting and reinforcement planting.The results showed that the spatial structure was improved obviously and trees diversity and stand health were not weakened.It’s suggested that the established optimization model can effectively guide multifunction management,stand structure optimization and the steadiness of ecological ecosystem and it is convenient and operable in practice,and it’s very important to protect and recover ecosystem of Water Resource Conservation Forests.  相似文献   

10.
This paper proposes an automatic method of pore combination recognition,which is an important feature to hardwood recognition.After extracting edge from wood microscopic cross-section, based on area histogram of the similar circle regions,the method classifies all regions into two classes with maximum between-class variance,so as to distinguish the pore from other textures,which are similar in shapes but different in sizes.Meanwhile, second objective function about average area of closed regions is used to improve the pore segmentation performance.At last,the method uses adjacency degree of pore set to judge pore combination.The experiments demonstrate that the task of pore segmentation can be completed successfully for all kinds of pore distribution and combination,and also the correct combinations of pores are given.  相似文献   

11.
我国蓝莓研究   总被引:1,自引:0,他引:1  
从蓝莓生产、繁殖、育种等角度综述了我国蓝莓研究现状,并提出今后蓝莓研究热点。我国虽然开展了一定规模的蓝莓种植,但栽培技术不高、效益不好是制约我国蓝莓生产的重要因素,尤其是内蒙古大兴安岭地区极具优势的野生蓝莓栽培生产尚未成熟是一件十分遗憾的事;从繁殖方式上看只有少部分品种实现了快繁,有较多的优良引进品种的快繁体系尚未建立,所以快繁技术还有待于进一步完善,特别是内蒙古大兴安岭高寒地区野生蓝莓的快繁技术的研究还处于研究阶段;种子繁殖正处于起步阶段;蓝莓育种技术的研究在我国尚属空白,生产中使用的品种均为引进种,这些品种耐寒性差,越冬防寒技术要求高是栽培推广的限制因素,而内蒙古的野生蓝莓品种虽然耐寒性强,但产量低、果实贮藏性差、栽培成活率低也是生产中的棘手问题,因此,选育出我国自主蓝莓品种是当务之急,尤其以大兴安岭高寒地区野生蓝莓为基础的新品种培育将成为今后我国蓝莓研究的重要方向。  相似文献   

12.
The most common trees on farm homesteads in Bangladesh were bamboo (several spp.), jackfruit (Artocarpus heterophyllus), mango (Mangifera indica), betelnut (Areca catechu), and jujube (Zizyphus jujube) in all agroecological zones studied. There were regional differences in the less common species. Species for new homestead planting were chosen mainly by women and tended to include indigenous fruit trees and a few exotics of high timber value. Choices were later influenced by new experience with exotic tree species and by perceptions from secondary information sources. Farmer-managed action-research was used to test the survival and performance of new trees planted under the Village and Farm Forestry Programme (VFFP). The main factors influencing tree survival were the role of women in selection of species and planting site, the degree of personal attention paid aftercare by the owner, and the quality and size of the planting stock. Biophysical factors and agroecological zones were unimportant. Main recorded causes of tree mortality were, in order of importance: damage by livestock, pests or diseases, physical damage by people (mainly children playing), and drought. Cause of death could not be attributed in about 35% of mortality, suggesting that the recorded causes should be treated with caution. Previous articles 1 and 2 in the series appeared in Agroforestry Systems 25: 193–216 and 31: 39–57 with slightly different main titles.  相似文献   

13.
北京西山灌木林小流域暴雨径流研究*   总被引:3,自引:0,他引:3       下载免费PDF全文
利用北京西山次生灌木林地上6个小流域的实测降雨径流数据,采用IUH法,分析影响径流的主要因子,并对降雨径流进行预测,结果表明:IUH法在小流域上应用效果较好,对径流过程的拟合较为一致;天然次生灌木林具有良好的水源涵养功能,在森林植被覆盖率超过40%时,每增加10%,IUH洪峰可降低4.6%,洪峰滞时可延长9.3%。  相似文献   

14.
基于水经注探讨乌兰布和沙漠景观形成问题   总被引:1,自引:0,他引:1  
根据北魏时期郦道元地理名著《水经注》中关于乌兰布和段黄河故道及其与黄河沿岸古城的位置关系,修正了有关现在黄河河道来源、沃野故城被黄河改道冲毁等论断,并从沙源与沙漠内涵、地表大面积流沙裸露堆积形成沙漠景观以及《水经注》中没有记录乌兰布和段沙漠景观等方面探讨了在乌兰布和沙漠景观的形成时间问题。  相似文献   

15.
以“天保”工程和振兴东北老工业基地进入攻坚阶段为契机,针对大兴安岭国有林区的“两危”现状,提出了北药开发是振兴林区经济的发展出路,并分析了北药开发的多种制约因素,重点探讨了大兴安岭国有林区北药开发产业的基本思路和布局。  相似文献   

16.
Seasonal yields of wetland rice and wheat were measured under traditionally-managed field trees of five species in northwestern Bangladesh over four years. There was a variable depression of rice (Oryza sativa) and wheat (Triticum aestivum) yields under all tree species. Yield depression overall ranged from 16% for the light-canopiedAcacia catechu to a little over 40% for the dense-canopiedArtocarpus heterophyllus andMangifera indica. Percentage yield depression was independent if agroecological zones, years, and location of the trees on the margins of centrally in a field. Yield depression in the dry season extended further in area than in the wet season; and for most tree species was to some extent alleviated by availability of irrigation. Farmers were well aware of and accepted crop yield losses under different tree species in return for the tree products. Trees with greatest impact on crops yielded products of highest value, mainly fruits and leaf fodder. Previous articles 1, 2 and 3 in the series appeared in Agroforestry Systems 25: 193–216, 31: 39–57 and 33: 231–247 respectively, with slightly different main titles.  相似文献   

17.
指出了重金属污染现象在中国日益严重,其中也包括镉污染在内,而“痛痛病”是由慢性镉中毒引发的最典型的疾病,通过对“痛痛病”的全面研究,有益于人们在前人的基础上,对当今社会的镉污染事件进行反思。在文献综述的基础上对“痛痛病”的起因、经过、处理的结果,以及日本政府所采取的措施,进行了详细的介绍与分析。  相似文献   

18.
对当前绿化造林中出现一些问题的思考   总被引:1,自引:0,他引:1  
对本市绿化造林中出现的新问题,提出了宜采取的对策,旨在引起领导的关注和有关部门的重视,以促进宁波市林业事业的持续,快速,健康发展。  相似文献   

19.
大庆苏打盐碱地造林研究   总被引:1,自引:0,他引:1  
本研究采用田间试验法,应用微生物肥料进行植树造林,栽植树木为16个品种。在不同时间内,采集植物和土壤样品,分别测定树木的形态、生理生化等指标;测定土壤物理、化学参数。经过2004-2007年连续4a的野外观测,通过对比施用活性微生物菌肥与不施用肥料的盐碱土上种植乔木和灌木等绿化树种生长状况进行研究。结果表明,施用活性微生物菌肥的乔木、灌木在成(存)活率、生物量、乔木胸径、新梢生长量、叶绿素含量、根系发育和生长势等各个方面均明显优于对照树木。因此,有望应用活性微生物菌肥在盐碱地的造林方面进行推广。本试验证明微生物肥料可以在盐碱土中广泛使用,在一定程度上能改善盐碱土的理化性质,提高土壤肥力,促进树木的生长。  相似文献   

20.
美国银杏的研究现状   总被引:6,自引:0,他引:6  
银杏于1784年由英国引种到美国,美国有20多个州栽植或研究银杏。美国对银杏生长发育,雄株品种,营养繁殖,基生树瘤,组织培养,性型表达,人工栽培,叶用成分及抗病虫机理等方面均有研究。  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