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运用模糊数学方法对榆林地区樟子松适宜情况进行分析,分析结果将榆林地区分成三种类型:适宜区、较适宜区和排灌条件好的引种适宜区。说明水分条件是樟子松引种成败的关键。 相似文献
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扶桑,在我省的温、热地带都有栽培。由于易繁殖、易管理、花色多,深受广大城乡群众所喜爱,有的栽培于家庭,有的盆栽于阳台,玉溪市还将扶桑选定为市花。扶桑品种较多,常见的有红灯笼、醉西施、粉牡丹、黑牡丹、御黄底等。这些不同品种的扶桑,有鲜红、粉红、桔黄、桔红等多种颜色,花朵还有重瓣、单瓣之分,形态各异。近两年来,笔者采取嫁接的方法,将不同花形、花色的扶桑集于一株,其嫁接方法如下: 一、培养砧木:不同花色、花形的扶桑都可互作砧木,互作接穗,但一般以选用春天萌发较早的黑牡丹,醉西施作砧木较好。砧木上盆栽植后,首先要注意培养分枝骨架和造形,从而为嫁接和树形打好基础。先让砧木中、上部的萌发枝自然生长(扶桑多为扦插繁殖,一般没有顶梢),主茎下部5厘 相似文献
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林业部徐有芳部长1994年8月中旬专程到榆林地区视察治沙工作,对榆林地区的治沙给予了充分肯定。并于8月20日对今后进一步搞好沙区综合治理做了重要指示。现根据徐部长的讲话录音整理如下,标题系本刊所加。 相似文献
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《中国森林病虫》2017,(1)
选用驳骨丹Buddleja asiatica苗、扶桑Hibiscus rosa-sinensis苗、蟛蜞菊Wedelia chinensis、马铃薯Solanum tuberosum块茎和南瓜Cucurbita moschata果实等材料繁殖与饲养扶桑绵粉蚧Phenacoccus solenopsis Tinsley,综合分析蚧虫存活率、接种蚧虫的难易、蚧虫发育情况、寄主材料的耐存性及管理、寄生蜂采收难易、材料成本、发育历期等因素。结果表明:南瓜是室内扩繁扶桑绵粉蚧的最适寄主。天敌班氏跳小蜂Aenasius bambawalei Hayat在5种寄主繁育的扶桑绵粉蚧上的世代历期均在15 d以上,其中,在蟛蜞菊上发育所需要的时间最长,达(17.6±2.4)d,在驳骨丹苗、扶桑苗、马铃薯与南瓜上的发育历期差异不显著。 相似文献
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通过对陕北榆林地区王圪堵水库库区植物配置方式的探讨,论述了库区植物配置原则,分析了整体植物的配置布局,提出了榆林地区水库景观环境中植物品种的选择,以及各个品种的组团搭配方式,以期营造库区景观绿化环境,提升及美化库区整体生态环境。 相似文献
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泡桐叶片蛋白质多态性及其聚类分析(英文) 总被引：2，自引：0，他引：2
根据白花泡桐（Paulownia fargesii）、白花兰考泡桐（P.elongata f. alba）、毛泡 桐（P. tomentosa）、川泡桐（P. fargesii）、山明泡桐（P. lamprophylla）、成都泡桐 (P. albiphloea var chengtuensis)、鄂川泡桐（P. albiphloea）、南方泡桐（P. austra lis）、白花泡桐（P. fortunei）、兰考泡桐（P. elongata）叶片蛋白质单向电泳和双向 电泳结果，可将它们聚类分为白花泡桐组（白花泡桐和白花兰考泡桐）、南方泡桐组（南方 泡桐和成都泡桐）和毛泡桐组（毛泡桐、川泡桐、鄂川泡桐、山明泡桐和兰考泡桐）。该结 果为泡桐属植物的分类提供了参考依据，也为泡桐属植物种确立、杂种鉴定和新品种培育奠 定了基础。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
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The development, longevity, fecundity and life-table parameters of the endoparasitoid Anagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae), 15 d.o. (3rd-instar nymphs) and 21 d.o. (young adult females) of the vine mealybug,
Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) at 28 ± 1°C, 65 ± 10%RH and 16:8h L:D under laboratory conditions. The developmental
time of female parasitoids within the host was 17.7 ± 0.39 days in 15 d.o. and 16.65 ± 0.25 days in 21 d.o. hosts; for males,
development time was 16.85 ± 0.29 and 15.25 ± 0.09 days, respectively. The average number of offspring per female was 22.35 ± 1.68
in 15 d.o. and 34.8 ± 2.56 in 21 d.o. vine mealybugs. The longevity of female parasitoids was 14.8 ± 0.98 days in 15 d.o.
and 15.65 ± 0.92 days in 21 d.o. mealybugs, respectively; for males, longevity was determined as 7.3 ± 0.43 and 6.7 ± 0.54 days,
respectively. The mean time of pupation was 7.85 ± 0.003 days in 15 d.o. mealybugs and 8.65 ± 0.003 days in 21 d.o. mealybugs.
The aggregate encapsulation rate in the parasitized 15 d.o. mealybugs was 49.73 and 60.36% in 21 d.o. mealybugs. Furthermore,
effective encapsulation was 24.82% in 15 d.o. mealybugs and 37.50% in 21 d.o. mealybugs. Population growth rate (r
m) for A. pseudococci was 0.0999 female/female/days in 15 d.o. mealybugs and 0.1269 female/female/days in 21 d.o. mealybugs. The mean population
generation time was 23.49 days for parasitoids reared in 15-days-old and 22.39 days when reared in 21 d.o. mealybugs. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
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There are abundant local legume trees and shrubs potentially suitable for alley cropping systems in the sub-Saharan Africa, which are yet to be studied. The nitrogen contribution of two years old Albizia lebbeck and S. corymbosato yield of maize grown in alley cropping was compared to that of Senna siamea, Gliricidia sepium and Leucaena leucocephala in four seasons at Ibadan. Maize shoot biomass and maize grain yield in A. lebbeck alley compared favourably with that in G. sepium and L. leucocephala. Maize biomass and grain yield in S. corymbosa alleys were the lowest. Within A. lebbeck, L. leucocpehala, and G. sepium alleys there were no significant differences in the maize yield in the alleys that received 0, 40 or 80 kg N/ha. Application of more than 40 kg N/ha in S. corymbosa alleys was not necessary as there was no significant increase in maize yield at the higher level of nitrogen. Maize yield and N uptake in A. lebbeck alleys were not significantly different from yield and N uptake in G. sepium, and L. leucocephala at the same fertilizer level. There was a significant correlation between hedgerow tree biomass and maize grain yield. At the end of twelve weeks after pruning application, the organic residues of the pruning applied in the alleys ranged from 5% in G. sepium and 44% in A. lebbeck in the first year compared with the original pruning applied which showed that the slow rate of A. lebbeck decomposition could have a beneficial effect on the soil. The maize N recovery from applied N fertilizer was low (10–22%). Percentage N recovery from the prunings was low in the non-N fixing trees (12–22%), while the recovery was high (49–59%) in A. lebbeck as well as in the other nitrogen fixing tree prunings. Thus A. lebbeck, apart from enhancing maize growth and grain yield like in L. leucocephala and G. sepium, had an added advantage because it remained longer as mulching material on the soil because of its slow rate of decomposition. It was able to survive pruning frequencies with no die-back. This indicates that A. lebbeck is a good potential candidate for alley cropping system in West Africa. S. corymbosa performed poorly compared with the other legume trees. Though it responded to N fertilizer showing a positive interaction between the hedgerow and fertilizer application, it had a high die back rate following pruning periods and termite attack.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
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Anders Ræbild Hanne H. Hansen Joachim Dartell J.-M. Kiléa Ky Lassina Sanou 《Agroforestry Systems》2007,70(2):157-167
Woody vegetation in cultivated landscapes in Burkina Faso is influenced by agricultural activities that are in turn influenced
by institutional arrangements. Research was undertaken in a village in south-west Burkina Faso to investigate the relationship
between species composition, diversity, density, species accumulation and land use category. Additionally the relationship
between number of trees, size of farmed land and farmer ethnicity was investigated. Indigenous Tiéfo farmers had on average
more than double the number of large (>4 m) trees of Vitellaria paradoxa Gaertn. f., Parkia biglobosa (Jacq.) R. Br. Ex G. Don and Anacardium occidentale L. than farmers belonging to other ethnic groups, but this was partly explained by a larger area being available. Differences
between ethnic groups were not significant when expressed per ha. Botanical inventories of fallows more than 4 years old,
cultivated parklands and plantations of Mangifera indica L. and A. occidentale showed that tree density and Simpson’s index of diversity for trees were highest in the fallow. Simpson’s index was not significantly
different for regeneration, but sample-based species accumulation curves indicated that species accumulation in parklands
was faster than in plantations when expressed per individual. The average regeneration density was 12,605, 1,995 and 6,772
seedlings ha-1 for fallow, parklands and plantations, respectively. This low density for parklands means that species accumulation is slow
compared to the other land uses when expressed per unit area. Fallow seems the most efficient way of keeping tree diversity
in the agricultural landscape. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
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J. Heuveldop H. W. Fassbender L. Alpízar G. Enríquez H. Fölster 《Agroforestry Systems》1988,6(1):37-48
During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha–1.a–1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity.Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha–1.a–1):
At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha–1.a–1.Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha–1.a–1 and underC. alliodora 7.07 t.ha–1.a–1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles.The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha–1.a–1):
For part I see Vol. 4, No. 3, 1986.Agroforestry Project, CATIE/GTZ (Tropical Agricultural Research and Training Center/Gesselschaft für Technische Zusammenarbeit), Turrialba, Costa Rica 相似文献
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Thaumetopoea solitaria is a serious pest of pistachio throughout the Mediterranean and the surrounding region. In this study, contact and ingestion
toxicities of Bifora radians,
Fumaria officinalis,
Humulus lupulus and Rhododendron ponticum extracts against T. solitaria larvae were examined under laboratory conditions. Dimethoate was used as a positive control. In the contact toxicity bioassays
B. radians extract was the most toxic, causing 32% mortality. In the ingestion toxicity bioassays H. lupulus extract was the most active, causing 83% mortality after 48 h. This shows that H. lupulus is acting as a stomach poison. The LC50 and LC90 values for H. lupulus ingestion toxicity bioassays were 1.7 and 8.7%, respectively. The LT50 value was 29.3 h. Since H. lupulus extract caused >50% mortality even 6 days after application, its long lasting residual effect promises fewer applications.
These results imply that H. lupulus has potential for use as a crop protectant against T. solitaria. 相似文献