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《热带农业科技》2000,(4)
调查补充光照对温室非洲菊Ｔｉｆｆａｎｙ(小花)和Ｏｐｔｉｍａ(大花)的影响。非洲菊栽培于岩棉基质,Ｔｉｆｆａｎｙ6株/ｍ2,Ｏｐｔｉｍａ4株/ｍ2。当自然光照为150Ｗ/ｍ2时进行补充光照(3000ｌｘ),每星期定期观测株花量、花柄长度、花重和花径。与对照相比,补充光照使Ｏｐｔｉｍａ品种单位面积花量显著增加,达33.5%,12月至翌年5月尤其如此。补充光照还使花柄更长(12～5月)和切花更重(10～3月)。补充光照后,Ｔｉｆｆａｎｙ品种的切花产量略微提高了6%,但是花径(10～12月)、花柄长度(11～4月)和花柄重量(10～5月)显著增加补充光照对非洲菊并… 相似文献
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非洲菊切花品种在攀枝花市有过少量栽培历史,但没有形成本地供给市场。一直以来,攀枝花的非洲菊切花主要来自昆明。为了实现非洲菊切花本地供给,经过在攀枝花市2 a来,8个品种的试验性栽培,表现良好,值得推广应用。本文将非洲菊在攀枝花市区的试验性生产过程进行了总结。 相似文献
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《热带农业科技》2000,(4)
调查热量对温室非洲菊Ｔｉｆｆａｎｙ(小花)和Ｏｐｔｉｍａ(大花)的影响。非洲菊栽培于岩棉基质,Ｔｉｆｆａｎｙ6株/ｍ2,Ｏｐｔｉｍａ4株/ｍ2。采用两种不同供热方式:地上和地下供热,昼夜温度分别为20℃和18℃。处理包括:同时使用两种供热方式(对照)以及如果单独使用地下供热(50℃)不能达到最低热量要求时使用地上供热方式。每星期定期观测株花量、花柄长度、花重和花径。地上供热使Ｏｐｔｉｍａ品种单位面积花量显著增加,达145.8枝(对照为117.6株),花柄显著变短(9～4月)。Ｔｉｆｆａｎｙ花的产量无显著变化(分别为286.8和240朵/ｍ2),然而花… 相似文献
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彩色马蹄莲引种栽培技术初探 总被引：4，自引：0，他引：4
对14个从荷兰引进的彩色马蹄莲品种，从种植时间、栽培基质、栽培密度和株型调控等研究其栽培技术，结果表明，春季的种植时间越晚，生育期越短，但对生长有一定不良影响，如使切花花枝变短等。用泥炭＋河沙＋园土（3：1：1）基质栽培可以生产出品质优良的切花和观赏价值高的盆花；合理密植可提高单位面积的切花产量而不影响质量，对于盆花则应根据株型来选择适宜的密度；用多效唑处理可使植株矮化，但各品种对多效唑的敏感度不同，多数品种的适宜质量浓度为1000mg/L。 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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《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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《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 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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本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 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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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):166-178
This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes. 相似文献