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采用灭幼脲Ⅲ号防治樟子松木蠹象幼虫和成虫，效果显，用3．75％灭幼尿Ⅲ号防治幼虫杀虫率达94．7％，处理后的幼虫表现出生长和发育受阻而死亡。用15％灭幼脲Ⅲ号处理成虫，使成虫产卵降低43．3％。61．4％，孵化率降为O；而对照组孵化率为85．8％。 相似文献
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灭幼脲与白僵菌混合防治马尾松毛虫效果研究 总被引：6，自引：0，他引：6
灭幼脲Ⅲ号胶悬剂与白僵菌孢子粉混合，用９０１烯释防治马尾松毛虫，其杀虫效果比二者单用分别提高９％～２８．８％和２１．９％～２９．６％。灭幼脲与白僵菌最优配比为灭幼脲１５０ｇ／ｈｍ＾２和灭幼脲２２５ｇ／ｈｍ＾２加白僵菌４５ｇ／ｈｍ＾２。喷洒混合剂后，林间松毛虫取食量减省得．４％以上，幼虫僵虫率提高１７．５％左右。 相似文献
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灭幼脲Ⅲ号防治蜀柏毒蛾试验刘良才，周波，唐献春（中江县林业局）前言应用灭幼脲Ⅲ号对蜀柏毒蛾的室内和林间试验，分析出灭幼脲对蜀柏毒蛾３龄幼虫致死中浓度为５．０３±０．１５９ｐｐｍ，１０ｐｐｍ～２０ｐｐｍ处理３～６龄幼虫取食量减少２２．５４％～３８．４７... 相似文献
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本文利用25%灭幼脲Ⅲ号悬浮剂、25%灭幼脲Ⅳ号悬浮剂、1.8%阿维菌素乳油对桃小食心虫进行了防治试验。分别采用灭幼脲Ⅲ号和灭幼脲Ⅳ号200倍液、300倍液、400倍液、500倍液、600倍液5个处理,喷清水对照;阿维菌素1 500倍液、2 000倍液、2 500倍液、3 000倍液、3 500倍液5个处理,喷清水对照。每个处理5株树,3次重复,根据性诱剂监测,在蛾峰第3 d(6月末至7月初)喷施。结果表明：灭幼脲Ⅲ号500倍液、灭幼脲Ⅳ号500倍液、阿维菌素2 000倍液防治桃小食心虫,致使大量卵不能孵化,林间防治虫果率均降至2.20%以下;考虑经济、效果等因素,林间使用阿维菌素2 000倍液防治桃小食心虫,虫果率较对照平均下降79.16%。 相似文献
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使用25％灭幼脲Ⅲ号悬浮剂防治马尾松毛虫，试验结果证明：25％灭幼脲Ⅲ号悬浮剂1500～2000倍液对马尾松毛虫防治效果明显，虫口减退率达59．1％～64．65％。 相似文献
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灭幼脲可以同时杀死黄地老虎的卵，幼虫，亦可杀死部分成虫，并且要使未被杀死的雌成虫产卵和卵孵人受到极大的抑制。灭幼脲油剂杀死幼虫８４．０３％－１００％左右，胶悬剂杀死幼虫８２．６４－９８．６１％左右；灭幼脲油剂杀死卵８３．３３－９２．８６％左右，胶悬剂杀 卵５．５５－２２．２２％左右；灭幼脲油杀死成虫８．３３－９．０３％左右，胶悬剂可杀死成虫７．６４－９．７４＾左右。 相似文献
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3种粉剂防治鞭角华扁叶蜂幼虫药效试验研究 总被引：2，自引：0，他引：2
选用２．５％甲基对硫磷，９０％灭幼脲Ⅲ号原粉和３％敌死蜱，分别用陶土稀释５种浓度防治鞭角华扁叶蜂１－６龄幼虫，试验结果表明，７２ｈ死亡率，用２－８倍陶土稀释的２．５％甲基对硫磷达８７．６％～９７．９％，用２５－２５０倍陶土稀释的９０％灭幼脲Ⅲ号原粉达８５．６％－９７．１％，用２－８倍陶土稀释的３％敌死蜱粉剂达８５．４％－９９．２％，２．５％甲基对硫磷，９０％灭幼脲防治成本分别为２１．６５－２３．５ 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(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 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