薄壳山核桃苗圃警根瘤蚜防治试验

警根瘤蚜是薄壳山核桃苗圃中发生最普遍、危害最严重的害虫之一.经过6a 的防治试验,结果表明,采用育苗与种植水稻轮作的办法,能有效控制警根瘤蚜的危害,不污染环境,不增加生产成本,是最好的防治方法之一     

警根瘤蚜的生物学特性研究

通过定期室内外观察的方法,研究了美国山核桃警根瘤蚜的形态特征和生物学习学特性,重点记录其虫瘿的变化过程。结果表明,警根瘤蚜越冬卵于3月末4月初开始孵化,4月上中旬为孵化盛期,10月中旬开始产生越冬卵。警根瘤蚜成虫有多个形态,由越冬卵孵化出的为干母,干母在寄主的幼叶上形成第一代虫瘿。警根瘤蚜在寄主叶片上形成虫瘿,成虫、幼虫均在虫瘿内吸食叶片汁液,严重影响了美国山核桃的生长。     

薄壳山核桃病虫害调查及主要病虫害防治关键技术

在建德、新昌两地调查了薄壳山核桃的病虫害。初步查明薄壳山核桃病虫害62种,其中虫害59种,病害3种。发生较严重,对产量影响较大的是薄壳山核桃黑斑病、星天牛Anoplophora chinensis和警根瘤蚜Phylloxera notabilis。薄壳山核桃黑斑病病原按柯赫法则,根据病原菌培养和形态特征及其ITS序列,鉴定为小孢拟盘多毛孢Pestalotiopsis microspora(Speg.)。薄壳山核桃黑斑病在国内属首次报道。还提出了薄壳山核桃主要病虫害的综合防治措施。     

警根瘤蚜种群动态及其与温度的关系

警根瘤蚜Phylloxera notabilis是美国薄壳山核桃嫩叶尤其是苗期的重要害虫。为了摸清警根瘤蚜的发生规律,制订有效的防治对策,调查了南京地区警根瘤蚜的种群动态。结果表明,警根瘤蚜从4月下旬开始出现,5—6月虫瘿量呈不断增长态势,7—8月新形成的虫瘿数量和活虫瘿数量最多,9月以后活虫瘿数量急剧减少直到本世代完成,至10月底活虫瘿基本消失。7—8月是警根瘤蚜发生的高峰期。此外,虫瘿量与温度的相关性分析显示温度是决定警根瘤蚜种群数量的关键因素,平均温度最高的7—8月也是虫瘿增长数和总数最多的时期。     

不同药剂对薄壳山核桃警根瘤蚜的防治初报

测定内吸性药剂吡虫啉、乐果和敌敌畏对薄壳山核桃Carya illnoensis k.Koch警根瘤蚜Phylloxera notabilis的防治效果。试验结果表明,3种药剂施用后警根瘤蚜的数量均大幅减少,防效均在91%以上,以6%吡虫啉可湿性粉剂防效最好;施药4个月后,6%吡虫啉可湿性粉剂处理调控效应最好,株危害率和叶片危害率分别降低至3.3%和8.5%。生产上可选用6%吡虫啉可湿性粉剂进行防治。     

警根瘤蚜的生物学特性和防治

警根瘤蚜(Phylloxera notabilis pergande)又名长山核桃叶根瘤蚜,属同翅目根瘤蚜科,是随苗木由美国传入我国的外来虫种,现分布于江苏,浙江,是危害长山核桃的主要害虫之一。严重时,叶片上布满豆粒状虫瘿,植株生长缓慢,产量下降。为了寻求有效的防治途径,作者于1987～1990年通过田间调查,定虫观察和室内间断的饲养,认为该蚜在南京地区一年发生4代虫瘿,早春阻止干母上行是比较理想的防治方法。 1 形态特征 1.1 成虫 警根瘤蚜届叶瘿型根瘤蚜,成虫有6个型,即干母、无翅雌蚜、短翅雌蚜(性母)、长翅雌蚜(迁飞雌蚜)、雌蚜和雄蚜。 1.1.1 干母:干母系越冬卵孵化出来的无翅     

薄壳山核桃无性繁殖试验

对薄壳山核桃采用嫁接、枝插、根插3种育苗方法进行繁殖对比试验,结果表明:3种育苗方法都可以培育薄壳山核桃良种壮苗,苗木成活率以枝插方法最高,根插方法最低;3种方法所育苗木的生长量大小顺序为:2年生砧木嫁接1年生苗>根插2年生苗>1年生砧木嫁接2年生苗>枝插2年生苗。表明培育薄壳山核桃良种壮苗以2年生砧木嫁接最为理想。     

光肩星天牛幼虫空间分布型的研究

光肩星天牛是糖槭、杨、柳、榆等树种的主要蛀干害虫之一。通过测定6种不同的判断空间分布格局的聚集度指标,并应用Taylor幂法则和Iwao回归分析法,得出光肩星天牛幼虫空间分布型为聚集分布,聚集原因是由本身的生物学特性和环境异质性共同作用引起的;另外,根据距离干基部的不同位置划分为3个高度,得出不同高度的虫口数量在1％水平达显著差异,且2m以上的虫口数量最多。     

不同尿素施肥量对薄壳山核桃嫁接苗光合作用日变化的影响

[目的]以薄壳山核桃'波尼'品种2年生嫁接苗为材料,探讨5种不同尿素施肥量对苗木光合特性差异的影响,为薄壳山核桃良种壮苗繁育提供理论依据.[方法]利用Li-6400XT便携式光合仪,测定薄壳山核桃净光合速率、气孔导度、胞间CO2浓度、蒸腾速率、水分利用率、气孔限制值、空气CO2浓度、空气温度、叶片温度、相对湿度、叶片饱...     

薄壳山核桃果实品质综合评价体系构建

【目的】建立一套全面、科学又符合消费需求的薄壳山核桃果实品质综合评价方法,用于资源评价、良种选育、栽培管理评价等。【方法】收集453份薄壳山核桃果实样品的品质数据,根据果实的特点选择品质评价指标,分析指标数据分布特征,制定分级及赋值标准。应用层次分析法,建立薄壳山核桃果实品质综合评价模型方程。【结果】薄壳山核桃12项果实品质客观指标中,仁质量符合正态分布,其他11项指标呈较分散的偏态分布,各品种间品质差异显著,各项指标变异系数为10.10%～62.88%,α-亚麻酸含量、总糖含量、仁质量3项指标离散度较大,油酸含量、粗脂肪含量、果实横径3项指标分布较为集中。将12项薄壳山核桃果实品质客观评价指标按出现概率分为极低、低、中、高、极高5个等级;将6项感官品质评价指标分为极差、较差、中等、良好、优秀5个等级。应用层次分析法,将果实性状和果实生化品质2类客观品质指标与感官品质相结合构建多目标评价模型,将3个层次和18项评价指标,用1～9标度法构建判别矩阵,对相互间的重要性进行权衡,并进行一致性检验,计算各项指标的权重,最终得出模型方程。【结论】层次分析法适用于薄壳山核桃综合评价体系的构建。采用...     

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.