共查询到20条相似文献，搜索用时 187 毫秒
1.
2.
3.
祁连山林木种质资源保护与开发利用对策 总被引：1，自引：0，他引：1
祁连山林木种质资源丰富,建国以来进行了多方面的调查,掌握了森林植物种类和主要树种的分布、面积情况,初步开展了林木种质资源的保存,大力开展了主要树种青海云杉、祁连圆柏的育苗,积极探索了灌木树种育苗技术和外地优良树种引种试验,种苗产业发展较快。祁连山林木种质资源保护和利用中还存在资源家底不清、没有统一规划、林木良种基地建设不规范、造林育苗良种率较低、苗木生产基础条件差、乡土树种育苗品种少等问题。提出了加强祁连山林木种质资源保护利用的对策。 相似文献
4.
5.
本文在化验土壤的基础上，进行了青海云杉、祁连圆柏不同化肥种类和施肥量的试验。结果表明：施肥可使１１年生的云杉高生长增加４４．６￣１０６．４％，８年生的圆柏高生长增加１８．２￣６３．３％；各种化肥中，云杉以Ｎ、Ｐ、Ｋ复合肥效果最好，圆柏以Ｎ、Ｐ肥效果最好；施肥量云杉以每株施２００ｇ为宜，圆柏每株施５０ｇ为宜。 相似文献
6.
7.
洛基山刺柏、白云杉引进及繁育技术研究 总被引：1，自引：0，他引：1
依据气候相似性原理从加拿大引进洛基山刺柏和白云杉种子,根据其生物学特性,分别进行了不同的催芽处理,运用温室容器育苗技术,进行合理的基质配置和不同播种方式,用我国已有树种祁连圆柏、青海云杉、紫果云杉、川西云杉、沙地云杉作对照进行育苗试验,通过试验观测,在苗期(2~3 a)洛基山刺柏生长量远远大于祁连圆柏;白云杉生长量较紫果云杉高,较川西云杉、沙地云杉低,与青海云杉很接近。从苗期适生性来预测,洛基山刺柏、白云杉有望成为适宜青海省或相似寒旱地区造林新树种。 相似文献
8.
以张掖灌区常用的樟子松、青海云杉、祁连圆柏、杜松、侧柏、油松、刺柏和华北落叶松8个针叶树种为研究对象,采用多变量综合分析法,对蒸腾强度、水势、自由水含量、束缚水含量、束缚水/自由水和含水量6个指标进行测定,对原始数据进行无量纲标准化处理,组成bij/MaxNj=aij矩阵,以Pi=∑i(1-aij)2值作为抗旱性能综合评判指标,结果表明,抗旱序列为:杜松>樟子松>青海云杉>油松>祁连圆柏>侧柏>刺柏>华北落叶松。 相似文献
9.
甘肃祁连山国家级自然保护区是我国生物多样性保护的重要基地，也是国际生物多样性保护的重点区域。祁连山自然保护区优势乔木树种主要有青海云杉、祁连山圆柏、杨树、华北落叶松、桦树、油松等，以青海云杉为主的祁连山水源涵养林作为祁连山及河西走廊绿洲生态系统的主体，具有巨大的经济、生态和社会价值。在祁连山自然保护区内科学地开展林业检疫性有害生物风险管理是祁连山森林可持续发展战略的重要内容之一。 相似文献
10.
张掖市寺大隆林场地处祁连山北麓、黑河中上游地带的肃南裕固族自治县境内。林场总经营面积262.86万亩,约占张掖市总土地面积的4.2%,其中林地面积93.3万亩,活立木总蓄积量达313万立方米,约占张掖市林木总蓄积量的20%。寺大隆林区由于受森林和高山冰川的湿岛效应,形成了适合多种动植物生存的环境,林区现有青海云杉、祁连圆柏等维管植物84科339属936种,有雪 相似文献
11.
12.
13.
14.
以太行山片麻岩山区天然植被退化形成的荒草坡、基岩裸露的灌草坡及人工爆破整地形成的隔坡梯田台面和覆土梯田坡面4种立地类型为研究对象,通过植生袋、鱼鳞坑、营养钵、撒播等造林技术,在4种立地类型上进行乔灌草人工植被恢复技术试验示范,研究了不同立地类型的物种多样性变化。物种多样性调查结果表明:在灌木层中,荆条是天然退化山地的绝对优势种,多花胡枝子和荆条是人工整地梯田坡面的优势种,其他物种主要有酸枣、臭椿,灌木层生态优势度指数、物种多样性指数及均匀度指数由大到小顺序均为梯田坡面、梯田台面、荒草坡、灌草坡;草本层主要物种有中华隐子草、狗尾草、早熟禾、碱蓬、地梢瓜等,物种多样性指数由大到小依次为梯田台面、灌草坡、荒草坡、梯田坡面,而均匀度指数略有不同,其由大到小依次为梯田台面、荒草坡、灌草坡、梯田坡面,物种丰富度指数由大到小依次为灌草坡、梯田坡面、梯田台面、荒草坡,草本层物种丰富度明显高于灌木层,鲜有低矮乔木。不同造林技术试验结果表明:简易植生袋坡面恢复技术措施在基岩裸露的陡坡上实施1a后,萌发生长的紫花地丁和二月兰的保存率低,恢复状况差,植生袋破损严重,坡面稳定性差,难以实现恢复效果;灌草坡鱼鳞坑造林技术实施1a后,金叶榆、侧柏、黄栌、榆叶梅和樱花的存活率分别为99%、99%、85%、67%和48%,其中金叶榆、侧柏和黄栌的生长状况明显优于榆叶梅和樱花;荒草坡面撒播植被恢复技术实施1a后,紫苜蓿存活状况较好,紫花地丁和二月兰存活状况差,二月兰几乎无一存活;梯田坡面营养钵造林技术实施1a后,沙地柏成活率不足5%;梯田台面客土经济林营造技术实施结果表明:山桃、山杏、苹果、核桃都可以在片麻岩梯田台面上较好生长,经过合理的培育管理,能够取得可观的经济效益。 相似文献
15.
《林业研究》2021,32(1)
Wetland restoration had been implemented for more than two decades in Sanjiang Plain,Northeast China.To assess the restoration efficiency of wetland vegetation,we investigated plants composition of community,plant species diversity and aboveground biomass of restored sites in a chronosequence of restoration(1,2,3,6,8,11,15 and 25 years) in the Sanjiang Nature Reserve.As comparison,we also investigated the same factors in a cropland and a natural marsh adjacent to the restored sites.The results showed that wetland plant species can invade quickly after croplands were abandoned when there were suitable hydrology conditions.On the early stage of the restoration,weeds were main plant species in the restored sites.Wetland species appeared at the same time but differed from the dominant species from the adjacent natural marshes.Common native wetland species could dominance the community after 3-year restoration.Species richness and diversity increased on the early stage,and then decreased to the similar level of the natural marsh with the extension of restoration.Plant biomass could restore easier than the species composition and diversity.Our results indicated that plant species composition and diversity of abandoned reclaimed wetlands can restore gradually by natural succession in S anjiang Plain.However,25-year restoration site had similarity index of only 56% with the natural marsh,which revealed that two decades are not enough for complete restoration of vegetation. 相似文献
16.
17.
河北省主要鸭梨产区杂草发生调查及除草剂药效评价 总被引：1，自引：0，他引：1
为了有效防控河北省鸭梨田主要杂草,采用倒置"W"九点取样法对杂草发生情况进行调查,结果发现,单子叶杂草发生与危害高于双子叶杂草,单子叶杂草主要有8种,其中马唐、牛筋草的优势度较高,分别为111.17和86.52;对200g/L草铵膦水剂、41%草甘膦异丙胺盐水剂2种除草剂药效评价发现,2种药剂随着用量的增加对杂草的防除效果提高,但在P=0.05水平和P=0.01水平上差异均不显著,表明草甘膦和草铵膦是梨区杂草苗后茎叶处理的良好除草剂。 相似文献
18.
The response of hybrid poplar plantations established on former agricultural land in Saskatchewan to competition from weeds
on a range of site productivities was studied. The short-term impact of competition control on the growth of juvenile trees
and how tree responses to competition control differed across the productivity gradient was of particular interest, as was
the determination of which resource was most highly competed for and was most important in determining tree growth. Eight
sets of paired plots in juvenile hybrid poplar plantations were established in central Saskatchewan across a range of site
productivities. In each pair, one plot had complete weed control (weed-free) while in the other plot weeds were allowed to
grow. The best soil predictor of tree growth was soil texture, represented by a combination of the percentage silt and clay,
with finer textures showing better growth. Competition control significantly increased tree growth on all sites with the benefit
being greatest on the higher productivity sites. Soil water appeared to be highly competed for between trees and weeds and
was a dominant resource controlling growth. For soil nutrients, nitrogen and phosphorous were highly competed for between
trees and weeds. However, leaf phosphorous concentration of the weed-free plots had a strong positive relation to tree growth
while nitrogen did not, indicating that when trees are free of competition they can access sufficient nitrogen from these
soils. 相似文献
19.
Weeds in tropical agricultural systems can cause serious economic damage, and their control often requires the commitment of substantial resources in the way of labor, capital, or pesticides. Tropical shifting cultivation systems employ a fallow period to help overcome weed infestations in addition to improving soil productivity and reducing other pest populations. Short-term, intensive fallow systems that employ herbaceous and woody species to facilitate rapid restoration of soil productivity have evolved as an alternative to long-term fallows. Short-term fallows can impact weeds at all growth stages and play a role in the integrated management of weeds and crops. Fallow management that promotes vegetative soil cover may reduce weed recruitment due to attenuation of soil temperature and/or shift in light quality at the soil surface. Residues or litterfall from fallow species may alter the chemical and microbial ecology of the soil to favor losses from the weed seed bank due to germination, loss of seed vigor, or seed decay. In addition, fallow vegetation can influence weed seed predation. Enhancement of soil productivity should increase the vigor of crop growth and enable crops to better compete with weeds. The burning of fallow species residues may result in weed seed death due to extreme temperatures or may induce seed germination by the release of mechanical dormancy or chemical germination cues. Certain weeds may serve as improved fallow species due to their high nutrient scavenging efficiency in low-fertility environments and their ease of establishment. Short-term improved fallows can be an important component of integrated weed management, particularly by promoting the prevention and tolerance of weeds in crops.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
20.
对北京西部黄羊滩流动沙地、半固定沙地和固定沙地3个演替阶段的植物群落进行取样分析,结果表明,物种丰富度随演替的进展呈增加的趋势,每一阶段对应着不同的优势种群.藜科植物是流动沙地的先锋植物,在植被演替早期具有不可替代的作用,且在各阶段种类数量比较稳定;菊科植物属于演替的过渡类群,只是在半固定沙地阶段表现出较高的优势度;禾本科和豆科植物呈不断增加的趋势,成为固定沙地生态功能的主要维持者.随演替的进展,初期占绝对优势的1年生植物逐渐被多年生植物替代,沙地植被向杂草类草原方向发展,生态系统趋于稳定.各阶段群落间的生态距离较远,在人工植被建设时应根据沙地环境条件选择最佳植物种和配置. 相似文献