紫红短须螨的生物学特性及其应用研究

微甘菊是我省的1种对农业、林业生产及环境能造成很大的破坏性杂草,为了有效地对其进行控制,利用紫红短须螨(Brevipalpusphoenicis)——薇甘菊的一种重要天敌对其进行试验。结果表明:在室内、外试验,每瓶或每盆薇甘菊中接种50～200头紫红短须螨,45～89d后,薇甘菊茎叶全部黄化或死亡;在野外大田中接种,159d以后,形成明显的中心枯死区,并且逐渐扩大.因此,用紫红短须螨控制薇甘菊可望成为的一个新途径.     

竹裂爪螨天敌--余杭植绥螨的研究

余杭植绥螨是竹裂爪螨的重要天敌.室内20℃恒温饲养余杭植绥螨需21.2 d完成一个世代、28℃则10.4 d就可完成,30℃以上出现死亡.幼螨、第1若螨和雄成虫捕食量相对较少,雌成螨每天平均捕食竹裂爪螨5.5头,最多可捕食13头,雌成螨期最多可捕食165头.雌成螨捕食量大,发育即加快,产卵量增加,产卵期延长,卵粒个体也加大.一头雌成螨一生产卵量7～15粒,卵产于竹叶背面基部茸毛丛中或竹裂爪螨的丝网内.余杭植绥螨随竹裂爪螨种群数量的消长而消长,竹裂爪螨在浙江有二个明显的高峰期,其每个高峰期5～7 d后,余杭植绥螨也出现明显的高峰期;而余杭植绥螨每次高峰期后6～9 d,竹裂爪螨发生量就明显下降.     

赤松人工栽培繁育技术

赤松(Pinus densiflora)松科松属。乔木，高可达30m，胸径达1．5m；树皮桔红色，裂成不规则的鳞片状块片脱落，树干上部树皮红褐色；叶2针1束，长5～12cm，径约1mm，先端微尖；雄果淡红黄色，圆筒形，长5～12mm，聚生于新枝下部呈短穗状，长4-7cm；雌果淡红紫色，单生或2～3个聚生。1年生小球果的种鳞先端有短刺；球果成熟时暗黄褐色或淡褐黄色；种子倒卵状椭圆形．     

温度对竹盲走螨实验种群生长发育与繁殖的影响

在 16、2 0、2 4、2 8、32、36℃的 6种恒温条件下 ,以竹裂爪螨各螨态为饲料 ,系统研究了温度对竹盲走螨实验种群生长发育、繁殖的影响。结果表明 ,36℃条件下竹盲走螨不能完成世代发育。在 16～ 32℃范围内 ,各螨态的发育历期随温度升高而缩短 ,卵至成螨的发育历期在 16、2 0、2 4、2 8、32℃ 5种恒温条件下分别为 16 0 1、10 80、5 81、5 12和 4 6 8d ;世代发育起点温度和有效积温分别为 10 4 4℃和 93 77d·℃。分别用王 -兰 -丁模型和逻辑斯谛模型拟合了温度与发育速率的关系 ,其中王 -兰 -丁模型能更好地反映出竹盲走螨在高温下发育受到抑制的现象。产卵期和雌成螨寿命随温度的升高而缩短。平均每雌产卵量在 2 4℃最高 ,为 31 2 6粒 ,32℃条件下仅为 9 2 0粒 ,每雌产卵量 (Y)与温度 (T)之间呈二次抛物线关系Y =- 171 6 94 2 17 2 732T - 0 0 36 3T2 (R =0 96 4 8 )。用年龄等级法分析表明 16℃、32℃条件不利于竹盲走螨种群的生长发育和繁殖。     

甘肃景泰杏芽瘿发生规律研究初报

在甘肃景泰危害杏树的杏芽瘿是梅下毛瘿螨,1年发生10代以上,世代重叠。在18℃左右,若螨期5～6d,成螨期3～4d,卵期5～6d,完成一个世代需13～16d。通过室外群体发育进程的观察和室内单体饲养,结果基本一致。在调查的6个杏树品种中,＂安宁18＂受害最重,其次为曹杏、张公园和兰州大接杏,受害最轻的为金太阳杏、凯特杏。一般多年生老杏园、管理粗放的杏园受害较重,幼龄杏园、管理精细的杏园受害较轻。     

枣树红蜘蛛在自然变温下有效积温的研究

该文对枣粮间作地中枣树红蜘蛛──截形叶螨的卵、幼螨、前若螨、后若螨４个虫期在自然变温下的有效积温进行了研究，结果表明，卵的发育起点温度１４．８±１．５６℃，有效积温为３９．３５６３日度；幼螨发育起点温度为１１．５±２．７３℃，有效积温为２７．８４日度；前若螨发育起点温度为１１．０±２．０８９℃，有效积温为４２．１３４７日度；后若螨发育起点温度为１２．８±１．８７℃，有效积温为３７．１日度；世代发育起点温度为１１．２±１．８３６℃，有效积温为１１６．２４４６日度。年发生１３代。     

红桦育苗及造林

红桦(Betula Albo—sinensis Burkill)，又名纸皮桦，为桦木科植物，落叶乔木或灌木，树高15～20m，胸围60～80cm，树形端直；树皮桔红色，有光泽，小枝无毛，紫褐色，具脂点，幼时生长快，树皮有横纹(象许多薄纸合成)，易剥落。叶片卵状或椭圆形卵状，长5～10cm，先端渐尖，基部圆形或宽楔形，叶缘有重锯齿。果序长3—3．5cm，果翅膜质，一般生长在海拔1900m以上．喜阴树种，耐寒，适应褐色土壤。     

红桦育苗及造林

红桦为桦木科植物，落叶乔木或灌木，树高15～20米，胸围60～80厘米，树形端直；树皮桔红色，有光泽，小枝无毛，紫褐色，具脂点，幼时生长快，树皮有横纹(像许多薄纸合成)，易剥落。叶片卵状或椭圆形卯状，长5～10厘米，先端渐尖，基部圆形或宽楔形，叶缘有重锯齿。果序长3～3．5厘米，果翅膜质，一般生长在海拔1900米以上．喜阴树种，耐寒，适应褐色土壤。     

松天牛小首螨的研究Ⅰ.生物学特性

【目的】松天牛小首螨是新发现的对松褐天牛卵具有寄生和致死作用的微型螨类,研究阐明其生物学特性,为利用该螨防治松褐天牛提供基础依据。【方法】通过室内饲养、显微观察和控制性试验,研究松天牛小首螨的行为习性、寄生率、发育历期、繁殖力和寿命等。【结果】松天牛小首螨属携播螨类,成螨附着在松褐天牛成虫胸腹部,在天牛产卵时沿产卵器爬行到刻槽中寄生天牛卵。该螨营两性生殖,雌成螨寄生天牛卵后腹部膨大形成膨腹体,若螨在母体膨腹体内完成发育,成螨自膨腹体胎生,1个膨腹体通常只产1～2头雄螨,其余均为雌螨。雄成螨先自膨腹体爬出并停留在旁,雌成螨自膨腹体爬出后即寻找雄成螨交尾,交尾过程持续3～6 s。松天牛小首螨对松褐天牛卵的平均寄生率为80.85%,被寄生的松褐天牛卵均干瘪、死亡。温度对该螨发育历期、雌成螨寿命和膨腹体大小均有显著影响,随着温度升高其发育历期和雌成螨寿命均显著缩短。该螨在17℃下的平均发育历期为6.9天,在33℃下为2.2天,其发育起点温度为(10.44±0.09)℃,有效积温为(46.28±0.28)d·℃;雌成螨在15℃下的平均寿命为70.3天,在30℃下为10.7天;雌螨膨腹体体积在21...     

胭脂虫实验种群研究

利用人工气候箱,按照正交设计方法,设置了8种不同温度、湿度、光照条件组合,运用生命表技术,对胭脂虫进行了种群动态研究。研究结果表明：15℃以下,胭脂虫卵有少量孵化,但不能完成世代;2D、25、30℃条件下胭脂虫能完成世代。从培育的胭脂虫的怀卵量、种群趋势指数及大小方面比较,以温度25℃、相对湿度60％和80％、光照强度980lx和601x的组合条件为好;胭脂虫的雌雄性比远大于1：1,环境因子对性比具有较大的影响;胭脂虫的种群趋势指数一般大于20,平均约40,对培育十分有利;发育起点温度为9．0℃,世代有效积温为822．9日度;多因素方差分析结果显示,温度为影响胭脂虫发育的最显著因素,而湿度和光照的影响相对较小。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

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.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

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.     

CAD与建筑设计的关系

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

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.     

Risk Perception Among Non-industrial Private Forest Owners

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.     

Interactions in decomposition and N mineralization between tropical legume residue components

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.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

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.