西北干旱区文冠果不同繁育技术研究

为了探寻适宜西北干旱区的文冠果繁殖方法与技术,以甘肃选择出的文冠果优良单株为繁殖材料,于2014—2016年对文冠果主要的苗木繁殖方法(播种繁殖、根插繁殖、嫁接繁殖)进行了对比试验研究。结果表明:1)根插繁殖的成活率最高,平均出苗率75.33%;其次是播种繁殖,达50%;嫁接繁殖成活率较差,为27.40%。说明根插和种子繁殖适宜文冠果大规模育苗;2)覆膜播种和大田直播的平均出苗率相差不大,分别为51.31%和51.10%。说明文冠果也可直接大田播种;3)覆膜播种和大田直播均存在出苗不整齐的现象;4)由于砧木质量和低温的影响,嫁接成活率较低。研究认为,在西北干旱、缺水和风大的环境条件下,文冠果最好覆膜播种,播前种子最好进行催芽处理;嫁接最好低位培土嫁接或套袋嫁接。     

小叶白蜡播种育苗技术

本文对小叶白蜡(Fraxinus bungeana)播种育苗的播种时间、播种方式与覆盖方式3个较为重要的因素进行组合试验,以出苗率、苗高、地径作为调查指标,进行比较分析。得出了小叶白蜡播种育苗的最佳组合为春季土壤解冻后(4月15日)采用覆膜点播,用沙盖种的方式进行育苗,效果最佳。     

白刺地膜覆盖播种育苗试验

探讨了地膜覆盖技术在白刺播种育苗中的应用.结果表明:白刺种子经3种物理处理和4种浓度的ABT处理后,覆膜对种子出苗率和出苗速率的影响均差异显著,覆膜比未覆膜平均出苗率和出苗速率分别提高了5.83％和33.99％.覆膜对白刺苗木的苗高、地径和侧根数的影响差异显著,对根长的影响差异不显著;覆膜比未覆膜平均苗高、地径、根长、侧根数分别增长了88.71％、86.61％、1.97％、138.93％.白刺播种育苗时,采用覆膜+种子混沙冷藏处理和覆膜+种子100mg/L浓度ABT处理方式播种,其出苗率和出苗速率较高,且苗木的苗高、地径和侧根数的增长显著.     

临沂市文冠果播种育苗技术研究

为加快文冠果(Xanthoceras sorbifolia Bunge)良种繁育进程,进行播种育苗试验。采取沙藏、快速催芽和干藏3种方法处理种子,研究了不同处理方法和种子大小对种子发芽率、出苗率的影响、育苗地土质和播种深度对出苗率的影响,以及播种密度对文冠果生长的影响,结果表明:种子直径≥10mm且处理方法为沙藏的平均发芽率、出苗率最高,分别为90.33%、89.67%;沙藏种子育苗选择砂壤土地块且播种深度4~5cm的出苗率最高,达89.67%;文冠果育苗的合理密度为30cm×15cm和40cm×10cm。     

北方干旱地区刺槐覆膜播种育苗效果研究

为了提高我国北方干旱地区刺槐播种育苗效果,在播种育苗中设置了覆膜试验,比较覆膜后的种子出苗情况及苗木生长情况,结果表明:与未覆膜的刺槐处理相比,覆膜处理下的出苗率有所提高,达98.23%,比未覆膜的高19.3个百分点,差异达极显著水平;出苗时间比未覆膜提前2d;苗木的高、胸径及地径生长更旺盛,优质苗比例更高;越冬后覆膜处理的刺槐苗木抽干率比未覆膜的降低了25.33个百分点。     

石河子地区文冠果快速育苗及栽植要点

各地文冠果苗木的繁育多采用露地播种育苗,单位面积内出苗率低、生产周期长,对种子的消耗量大,成本投入高。在近几年文冠果苗木及种子供应紧张的情况下,我们借鉴本地葡萄容器育苗及棉花地膜覆盖滴灌种植技术     

青檀播种育苗技术研究

笔者介绍了太宽河保护区青檀的资源现状,从种子采集、种子处理、整地、播种方式与播种时间几方面阐述了青檀的播种育苗技术。同时分析了干藏秋播、干藏春播、砂藏春播3种不同处理对青檀种子出苗及幼苗生长情况的影响。结果表明,不同处理对青檀种子出苗率、苗木保存率、苗木生长量均有显著影响;以干藏秋播和砂藏春播苗木生长最好,以秋播处理用工最少。     

断胚根处理对文冠果育苗的影响及配套技术研究

研究了断胚根处理对生物质能源树种文冠果种子发芽成苗的影响。通过对不同时期的文冠果种子进行不同程度的断胚根处理,定量分析了文冠果种子断胚根的最佳处理时期,处理方法与再生根的数量、长度、根幅、直径,出苗率,苗高,冠幅的关系,解决了文冠果种子断胚根的关键技术指标和参数,并以此构成较为完备的文冠果育苗配套技术体系。结果表明:文冠果种子萌发期间,进行断胚根处理,可促进侧根增加,胚根长4cm,留根长2cm时,断胚根效果最显著;胚根斜切口处理的新生根数和根长优于平切口;断胚根处理后,文冠果当年生露地苗木的成活率比对照组提高14.16%,苗木平均高增加7.22cm。     

银杏秋季覆盖实生播种育苗研究

银杏在秋季采用稻草、麦秸和地膜覆盖实生播种育苗,出苗齐和苗木质量,都好于不覆盖（CK）裸地播种育苗。其中：地膜覆盖的出苗期都比CK提早17 d,出苗率、苗木高度、苗木粗度和苗木根系长度,分别比CK平均提高38.0%、8.2cm、0.25cm、和18.9cm,大幅度提高了出苗率,降低了育苗成本,建议在生产中推广该项技术。     

沙枣2种育苗技术效果对比试验

通过对沙枣进行扦插育苗和播种育苗试验,分析了2种育苗方法的效果,结果表明:沙枣扦插育苗苗木成活率65.0%,当年平均高生长量和地径生长量分别为58 cm和0.63 cm,第2年平均高生长量和地径生长量分别为104 cm和1.08 cm。春秋季种子育苗苗木出苗率分别为75.5%和93.5%,春季育苗当年平均高生长量和地径生长量分别为38 cm和0.37 cm,第2年平均高生长量和地径生长量分别为97 cm和0.86 cm;秋季播种1年生平均高生长量和地径生长量分别为40 cm和0.38 cm,第2年平均高生长量和地径生长量分别达到95 cm和0.87 cm。沙枣播种育苗出苗率高,单位面积载苗量大,经济效益高。     

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.